ops library API reference¶
ops module¶
The ops library: a Python framework for writing Juju charms.
The ops library is a Python framework (available on PyPI) for developing and testing Juju charms in a consistent way, using standard Python constructs to allow for clean, maintainable, and reusable code.
A charm is an operator – business logic encapsulated in a reusable software package that automates every aspect of an application’s life.
Charms written with ops support Kubernetes using Juju’s “sidecar charm” pattern, as well as charms that deploy to Linux-based machines and containers.
Charms should do one thing and do it well. Each charm drives a single application and can be integrated with other charms to deliver a complex system. A charm handles creating the application in addition to scaling, configuration, optimisation, networking, service mesh, observability, and other day-2 operations specific to the application.
The ops library is part of the Charm SDK (the other part being Charmcraft). Full developer documentation for the Charm SDK is available at https://juju.is/docs/sdk.
To learn more about Juju, visit https://juju.is/docs/olm.
- class ops.ActionEvent(handle: Handle)[source]¶
Bases:
EventBase
Events raised by Juju when an administrator invokes a Juju Action.
This class is the data type of events triggered when an administrator invokes a Juju Action. Callbacks bound to these events may be used for responding to the administrator’s Juju Action request.
To read the parameters for the action, see the instance variable
params
. To respond with the result of the action, callset_results()
. To add progress messages that are visible as the action is progressing uselog()
.- defer() None [source]¶
Action events are not deferrable like other events.
This is because an action runs synchronously and the administrator is waiting for the result.
- fail(message: str = '')[source]¶
Report that this action has failed.
- Parameters:
message – Optional message to record why it has failed.
- log(message: str)[source]¶
Send a message that a user will see while the action is running.
- Parameters:
message – The message for the user.
- restore(snapshot: Dict[str, Any])[source]¶
Used by the framework to record the action.
Not meant to be called directly by charm code.
- set_results(results: Dict[str, Any])[source]¶
Report the result of the action.
Juju eventually only accepts a str:str mapping, so we will attempt to flatten any more complex data structure like so:
>>> {'a': 'b'} # becomes: 'a'='b' >>> {'a': {'b': 'c'}} # becomes: 'a.b'='c' >>> {'a': {'b': 'c', 'd': 'e'}} # becomes: 'a.b'='c', 'a.d' = 'e' >>> {'a.b': 'c', 'a.d': 'e'} # equivalent to previous
Note that duplicate keys are not allowed, so this is invalid:
>>> {'a': {'b': 'c'}, 'a.b': 'c'}
Note that the resulting keys must start and end with lowercase alphanumeric, and can only contain lowercase alphanumeric, hyphens and periods.
If any exceptions occur whilst the action is being handled, juju will gather any stdout/stderr data (and the return code) and inject them into the results object. Thus, the results object might contain the following keys, additionally to those specified by the charm code:
Stdout
Stderr
Stdout-encoding
Stderr-encoding
ReturnCode
- Parameters:
results – The result of the action as a Dict
- class ops.ActionMeta(name: str, raw: Dict[str, Any] | None = None)[source]¶
Bases:
object
Object containing metadata about an action’s definition.
- class ops.ActiveStatus(message: str = '')[source]¶
Bases:
StatusBase
The unit is ready.
The unit believes it is correctly offering all the services it has been asked to offer.
- name = 'active'¶
- class ops.Application(name: str, meta: CharmMeta, backend: _ModelBackend, cache: _ModelCache)[source]¶
Bases:
object
Represents a named application in the model.
This might be this charm’s application, or might be an application this charm is related to. Charmers should not instantiate Application objects directly, but should use
Model.app
to get the application this unit is part of, orModel.get_app()
if they need a reference to a given application.- add_secret(content: Dict[str, str], *, label: str | None = None, description: str | None = None, expire: datetime | timedelta | None = None, rotate: SecretRotate | None = None) Secret [source]¶
Create a
Secret
owned by this application.- Parameters:
content – A key-value mapping containing the payload of the secret, for example
{"password": "foo123"}
.label – Charm-local label (or “name”) to assign to this secret, which can later be used for lookup.
description – Description of the secret’s purpose.
expire – Time in the future (or timedelta from now) at which the secret is due to expire. When that time elapses, Juju will notify the charm by sending a SecretExpired event. None (the default) means the secret will never expire.
rotate – Rotation policy/time. Every time this elapses, Juju will notify the charm by sending a SecretRotate event. None (the default) means to use the Juju default, which is never rotate.
- name: str¶
The name of this application (eg, ‘mysql’). This name may differ from the name of the charm, if the user has deployed it to a different name.
- planned_units() int [source]¶
Get the number of units that Juju has “planned” for this application.
E.g., if an admin runs “juju deploy foo”, then “juju add-unit -n 2 foo”, the planned unit count for foo will be 3.
The data comes from the Juju agent, based on data it fetches from the controller. Pending units are included in the count, and scale down events may modify the count before some units have been fully torn down. The information in planned_units is up-to-date as of the start of the current hook invocation.
This method only returns data for this charm’s application – the Juju agent isn’t able to see planned unit counts for other applications in the model.
- property status: StatusBase¶
Used to report or read the status of the overall application.
Changes to status take effect immediately, unlike other Juju operations such as modifying relation data or secrets, which only take effect after a successful event.
Can only be read and set by the lead unit of the application.
The status of remote units is always Unknown.
Alternatively, use the
collect_app_status
event to evaluate and set application status consistently at the end of every hook.- Raises:
RuntimeError – if setting the status of another application, or if setting the status of this application as a unit that is not the leader.
InvalidStatusError – if setting the status to something that is not a
StatusBase
Example:
self.model.app.status = BlockedStatus('I need a human to come help me')
- class ops.Binding(name: str, relation_id: int | None, backend: _ModelBackend)[source]¶
Bases:
object
Binding to a network space.
- class ops.BindingMapping(backend: _ModelBackend)[source]¶
-
Mapping of endpoints to network bindings.
Charm authors should not instantiate this directly, but access it via
Model.get_binding()
- class ops.BlockedStatus(message: str = '')[source]¶
Bases:
StatusBase
The unit requires manual intervention.
An admin has to manually intervene to unblock the unit and let it proceed.
- name = 'blocked'¶
- class ops.BoundEvent(emitter: Object, event_type: Type[EventBase], event_kind: str)[source]¶
Bases:
object
Event bound to an Object.
- class ops.BoundStoredState(parent: Object, attr_name: str)[source]¶
Bases:
object
Stored state data bound to a specific Object.
- class ops.CharmBase(framework: Framework)[source]¶
Bases:
Object
Base class that represents the charm overall.
CharmBase
is used to create a charm. This is done by inheriting fromCharmBase
and customising the subclass as required. So to create a charm calledMyCharm
, define a charm class and set up the required event handlers (“hooks”) in its constructor:import logging import ops def MyCharm(ops.CharmBase): def __init__(self, *args): super().__init__(*args) self.framework.observe(self.on.config_changed, self._on_config_changed) self.framework.observe(self.on.stop, self._on_stop) # ... if __name__ == "__main__": ops.main(MyCharm)
As shown in the example above, a charm class is instantiated by
ops.main
rather than charm authors directly instantiating a charm.- Parameters:
framework – The framework responsible for managing the Model and events for this charm.
- property app: Application¶
Application that this unit is part of.
- property config: ConfigData¶
A mapping containing the charm’s config and current values.
- on: CharmEvents[source]¶
This property is used to create an event handler using
Framework.observe()
, and can be one of the events listed atCharmEvents
.
- class ops.CharmEvents(parent: Object | None = None, key: str | None = None)[source]¶
Bases:
ObjectEvents
Events generated by Juju pertaining to application lifecycle.
By default, the events listed as attributes of this class will be provided via the
CharmBase.on
attribute. For example:self.framework.observe(self.on.config_changed, self._on_config_changed)
In addition to the events listed as attributes of this class, dynamically-named events will also be defined based on the charm’s metadata (
metadata.yaml
) for relations, storage, actions, and containers. These named events may be accessed asself.on[<name>].<event>
or using a prefix likeself.on.<name>_<event>
, for example:self.framework.observe(self.on["db"].relation_created, self._on_db_relation_created) self.framework.observe(self.on.workload_pebble_ready, self._on_workload_pebble_ready)
- collect_app_status¶
Triggered on the leader at the end of every hook to collect app statuses for evaluation (see
CollectStatusEvent
).
- collect_metrics¶
Triggered by Juju to collect metrics (see
CollectMetricsEvent
).
- collect_unit_status¶
Triggered at the end of every hook to collect unit statuses for evaluation (see
CollectStatusEvent
).
- config_changed¶
Triggered when a configuration change occurs (see
ConfigChangedEvent
).
- install¶
Triggered when a charm is installed (see
InstallEvent
).
- leader_elected¶
Triggered when a new leader has been elected (see
LeaderElectedEvent
).
- leader_settings_changed¶
DEPRECATED. Triggered when leader changes any settings (see
LeaderSettingsChangedEvent
).
- post_series_upgrade¶
Triggered after a series upgrade (see
PostSeriesUpgradeEvent
).
- pre_series_upgrade¶
Triggered to prepare a unit for series upgrade (see
PreSeriesUpgradeEvent
).
- remove¶
Triggered when a unit is about to be terminated (see
RemoveEvent
).
- secret_changed¶
Triggered by Juju on the observer when the secret owner changes its contents (see
SecretChangedEvent
).
- secret_expired¶
Triggered by Juju on the owner when a secret’s expiration time elapses (see
SecretExpiredEvent
).
- secret_remove¶
Triggered by Juju on the owner when a secret revision can be removed (see
SecretRemoveEvent
).
- secret_rotate¶
Triggered by Juju on the owner when the secret’s rotation policy elapses (see
SecretRotateEvent
).
- start¶
Triggered immediately after first configuration change (see
StartEvent
).
- update_status¶
Triggered periodically by a status update request from Juju (see
UpdateStatusEvent
).
- upgrade_charm¶
Triggered by request to upgrade the charm (see
UpgradeCharmEvent
).
- class ops.CharmMeta(raw: Dict[str, Any] | None = None, actions_raw: Dict[str, Any] | None = None)[source]¶
Bases:
object
Object containing the metadata for the charm.
This is read from
metadata.yaml
andactions.yaml
. Generally charms will define this information, rather than reading it at runtime. This class is mostly for the framework to understand what the charm has defined.- Parameters:
raw – a mapping containing the contents of metadata.yaml
actions_raw – a mapping containing the contents of actions.yaml
- actions: Dict[str, ActionMeta]¶
Actions the charm has defined.
- containers: Dict[str, ContainerMeta]¶
Container metadata for each defined container.
- extra_bindings: Dict[str, None]¶
Additional named bindings that a charm can use for network configuration.
- classmethod from_yaml(metadata: str | TextIO, actions: str | TextIO | None = None) CharmMeta [source]¶
Instantiate a
CharmMeta
from a YAML description ofmetadata.yaml
.- Parameters:
metadata – A YAML description of charm metadata (name, relations, etc.) This can be a simple string, or a file-like object (passed to
yaml.safe_load
).actions – YAML description of Actions for this charm (e.g., actions.yaml)
- payloads: Dict[str, PayloadMeta]¶
Payload metadata for each defined payload.
- peers: Dict[str, RelationMeta]¶
Peer relations.
- provides: Dict[str, RelationMeta]¶
Relations this charm provides.
- relations: Dict[str, RelationMeta]¶
All
RelationMeta
instances.This is merged from
requires
,provides
, andpeers
. If needed, the role of the relation definition can be obtained from itsrole
attribute.
- requires: Dict[str, RelationMeta]¶
Relations this charm requires.
- resources: Dict[str, ResourceMeta]¶
Resource metadata for each defined resource.
- series: List[str]¶
List of supported OS series that this charm can support.
The first entry in the list is the default series that will be used by deploy if no other series is requested by the user.
- storages: Dict[str, StorageMeta]¶
Storage metadata for each defined storage.
- class ops.CheckInfoMapping(checks: Iterable[CheckInfo])[source]¶
Bases:
Mapping
[str
,CheckInfo
]Map of check names to
ops.pebble.CheckInfo
objects.This is done as a mapping object rather than a plain dictionary so that we can extend it later, and so it’s not mutable.
- class ops.CollectMetricsEvent(handle: Handle)[source]¶
Bases:
HookEvent
Event triggered by Juju to collect metrics.
Juju fires this event every five minutes for the lifetime of the unit. Callback methods bound to this event may use the
add_metrics()
method of this class to send measurements to Juju.Note that associated callback methods are currently sandboxed in how they can interact with Juju.
- class ops.CollectStatusEvent(handle: Handle)[source]¶
Bases:
EventBase
Event triggered at the end of every hook to collect statuses for evaluation.
If the charm wants to provide application or unit status in a consistent way after the end of every hook, it should observe the
collect_app_status
orcollect_unit_status
event, respectively.The framework will trigger these events after the hook code runs successfully (
collect_app_status
will only be triggered on the leader unit). If any statuses were added by the event handlers usingadd_status()
, the framework will choose the highest-priority status and set that as the status (application status forcollect_app_status
, or unit status forcollect_unit_status
).The order of priorities is as follows, from highest to lowest:
error
blocked
maintenance
waiting
active
unknown
If there are multiple statuses with the same priority, the first one added wins (and if an event is observed multiple times, the handlers are called in the order they were observed).
A collect-status event can be observed multiple times, and
add_status()
can be called multiple times to add multiple statuses for evaluation. This is useful when a charm has multiple components that each have a status. Each code path in a collect-status handler should calladd_status
at least once.Below is an example “web app” charm component that observes
collect_unit_status
to provide the status of the component, which requires a “port” config option set before it can proceed:class MyCharm(ops.CharmBase): def __init__(self, *args): super().__init__(*args) self.webapp = Webapp(self) # initialize other components class WebApp(ops.Object): def __init__(self, charm: ops.CharmBase): super().__init__(charm, 'webapp') self.framework.observe(charm.on.collect_unit_status, self._on_collect_status) def _on_collect_status(self, event: ops.CollectStatusEvent): if 'port' not in self.model.config: event.add_status(ops.BlockedStatus('please set "port" config')) return event.add_status(ops.ActiveStatus())
- add_status(status: StatusBase)[source]¶
Add a status for evaluation.
See
CollectStatusEvent
for a description of how to use this.
- class ops.CommitEvent(handle: Handle)[source]¶
Bases:
LifecycleEvent
Event that will be emitted second on commit.
- class ops.ConfigChangedEvent(handle: Handle)[source]¶
Bases:
HookEvent
Event triggered when a configuration change occurs.
This event will fire in several situations:
When the admin reconfigures the charm using the Juju CLI, for example
juju config mycharm foo=bar
. This event notifies the charm of its new configuration. (The event itself, however, is not aware of what specifically has changed in the config).Right after the unit starts up for the first time. This event notifies the charm of its initial configuration. Typically, this event will fire between an
install
and astart
during the startup sequence (when a unit is first deployed), but in general it will fire whenever the unit is (re)started, for example after pod churn on Kubernetes, on unit rescheduling, on unit upgrade or refresh, and so on.As a specific instance of the above point: when networking changes (if the machine reboots and comes up with a different IP).
Any callback method bound to this event cannot assume that the software has already been started; it should not start stopped software, but should (if appropriate) restart running software to take configuration changes into account.
- class ops.ConfigData(backend: _ModelBackend)[source]¶
Bases:
LazyMapping
Configuration data.
This class should not be instantiated directly. It should be accessed via
Model.config
.
- class ops.Container(name: str, backend: _ModelBackend, pebble_client: Client | None = None)[source]¶
Bases:
object
Represents a named container in a unit.
This class should not be instantiated directly, instead use
Unit.get_container()
orUnit.containers
.- add_layer(label: str, layer: str | LayerDict | Layer, *, combine: bool = False)[source]¶
Dynamically add a new layer onto the Pebble configuration layers.
- Parameters:
label – Label for new layer (and label of layer to merge with if combining).
layer – A YAML string, configuration layer dict, or pebble.Layer object containing the Pebble layer to add.
combine – If combine is False (the default), append the new layer as the top layer with the given label (must be unique). If combine is True and the label already exists, the two layers are combined into a single one considering the layer override rules; if the layer doesn’t exist, it is added as usual.
- can_connect() bool [source]¶
Report whether the Pebble API is reachable in the container.
This method returns a bool that indicates whether the Pebble API is available at the time the method is called. It does not guard against the Pebble API becoming unavailable, and should be treated as a “point in time” status only.
For example:
container = self.unit.get_container("example") if container.can_connect(): try: c.pull('/does/not/exist') except ProtocolError, PathError: # handle it else: event.defer()
- exec(command: List[str], *, service_context: str | None = None, environment: Dict[str, str] | None = None, working_dir: str | None = None, timeout: float | None = None, user_id: int | None = None, user: str | None = None, group_id: int | None = None, group: str | None = None, stdin: str | TextIO | None = None, stdout: TextIO | None = None, stderr: TextIO | None = None, encoding: str = 'utf-8', combine_stderr: bool = False) ExecProcess[str] [source]¶
- exec(command: List[str], *, service_context: str | None = None, environment: Dict[str, str] | None = None, working_dir: str | None = None, timeout: float | None = None, user_id: int | None = None, user: str | None = None, group_id: int | None = None, group: str | None = None, stdin: bytes | BinaryIO | None = None, stdout: BinaryIO | None = None, stderr: BinaryIO | None = None, encoding: None = None, combine_stderr: bool = False) ExecProcess[bytes]
Execute the given command on the remote system.
See
ops.pebble.Client.exec()
for documentation of the parameters and return value, as well as examples.
- exists(path: str | PurePath) bool [source]¶
Report whether a path exists on the container filesystem.
- get_check(check_name: str) CheckInfo [source]¶
Get check information for a single named check.
Raises
ModelError
ifcheck_name
is not found.
- get_checks(*check_names: str, level: CheckLevel | None = None) CheckInfoMapping [source]¶
Fetch and return a mapping of check information indexed by check name.
- Parameters:
check_names – Optional check names to query for. If no check names are specified, return checks with any name.
level – Optional check level to query for. If not specified, fetch all checks.
- get_plan() Plan [source]¶
Get the combined Pebble configuration.
This will immediately reflect changes from any previous
add_layer()
calls, regardless of whetherreplan()
orrestart()
have been called.
- get_service(service_name: str) ServiceInfo [source]¶
Get status information for a single named service.
Raises
ModelError
if service_name is not found.
- get_services(*service_names: str) Mapping[str, ServiceInfo] [source]¶
Fetch and return a mapping of status information indexed by service name.
If no service names are specified, return status information for all services, otherwise return information for only the given services.
- isdir(path: str | PurePath) bool [source]¶
Report whether a directory exists at the given path on the container filesystem.
- list_files(path: str | PurePath, *, pattern: str | None = None, itself: bool = False) List[FileInfo] [source]¶
Return list of directory entries from given path on remote system.
Despite the name, this method returns a list of files and directories, similar to
os.listdir()
oros.scandir()
.- Parameters:
path – Path of the directory to list, or path of the file to return information about.
pattern – If specified, filter the list to just the files that match, for example
*.txt
.itself – If path refers to a directory, return information about the directory itself, rather than its contents.
- make_dir(path: str | PurePath, *, make_parents: bool = False, permissions: int | None = None, user_id: int | None = None, user: str | None = None, group_id: int | None = None, group: str | None = None)[source]¶
Create a directory on the remote system with the given attributes.
- Parameters:
path – Path of the directory to create on the remote system.
make_parents – If True, create parent directories if they don’t exist.
permissions – Permissions (mode) to create directory with (Pebble default is 0o755).
user_id – User ID (UID) for directory.
user – Username for directory. User’s UID must match user_id if both are specified.
group_id – Group ID (GID) for directory.
group – Group name for directory. Group’s GID must match group_id if both are specified.
- property pebble: Client¶
The low-level
ops.pebble.Client
instance for this container.
- pull(path: str | PurePath, *, encoding: str | None = 'utf-8') BinaryIO | TextIO [source]¶
Read a file’s content from the remote system.
- Parameters:
path – Path of the file to read from the remote system.
encoding – Encoding to use for decoding the file’s bytes to string, or
None
to specify no decoding.
- Returns:
A readable file-like object, whose
read()
method will return strings decoded according to the specified encoding, or bytes if encoding isNone
.- Raises:
pebble.PathError – If there was an error reading the file at path, for example, if the file doesn’t exist or is a directory.
- pull_path(source_path: str | PurePath | Iterable[str | PurePath], dest_dir: str | Path)[source]¶
Recursively pull a remote path or files to the local system.
Only regular files and directories are copied; symbolic links, device files, etc. are skipped. Pulling is attempted to completion even if errors occur during the process. All errors are collected incrementally. After copying has completed, if any errors occurred, a single
MultiPushPullError
is raised containing details for each error.Assuming the following files exist remotely:
/foo/bar/baz.txt
/foo/foobar.txt
/quux.txt
These are various pull examples:
# copy one file container.pull_path('/foo/foobar.txt', '/dst') # Destination results: /dst/foobar.txt # copy a directory container.pull_path('/foo', '/dst') # Destination results: /dst/foo/bar/baz.txt, /dst/foo/foobar.txt # copy a directory's contents container.pull_path('/foo/*', '/dst') # Destination results: /dst/bar/baz.txt, /dst/foobar.txt # copy multiple files container.pull_path(['/foo/bar/baz.txt', 'quux.txt'], '/dst') # Destination results: /dst/baz.txt, /dst/quux.txt # copy a file and a directory container.pull_path(['/foo/bar', '/quux.txt'], '/dst') # Destination results: /dst/bar/baz.txt, /dst/quux.txt
- Parameters:
source_path – A single path or list of paths to pull from the remote system. The paths can be either a file or a directory but must be absolute paths. If
source_path
is a directory, the directory base name is attached to the destination directory – that is, the source path directory is placed inside the destination directory. If a source path ends with a trailing/*
it will have its contents placed inside the destination directory.dest_dir – Local destination directory inside which the source dir/files will be placed.
- push(path: str | PurePath, source: bytes | str | BinaryIO | TextIO, *, encoding: str = 'utf-8', make_dirs: bool = False, permissions: int | None = None, user_id: int | None = None, user: str | None = None, group_id: int | None = None, group: str | None = None)[source]¶
Write content to a given file path on the remote system.
- Parameters:
path – Path of the file to write to on the remote system.
source – Source of data to write. This is either a concrete str or bytes instance, or a readable file-like object.
encoding – Encoding to use for encoding source str to bytes, or strings read from source if it is a TextIO type. Ignored if source is bytes or BinaryIO.
make_dirs – If True, create parent directories if they don’t exist.
permissions – Permissions (mode) to create file with (Pebble default is 0o644).
user_id – User ID (UID) for file.
user – Username for file. User’s UID must match user_id if both are specified.
group_id – Group ID (GID) for file.
group – Group name for file. Group’s GID must match group_id if both are specified.
- push_path(source_path: str | Path | Iterable[str | Path], dest_dir: str | PurePath)[source]¶
Recursively push a local path or files to the remote system.
Only regular files and directories are copied; symbolic links, device files, etc. are skipped. Pushing is attempted to completion even if errors occur during the process. All errors are collected incrementally. After copying has completed, if any errors occurred, a single
MultiPushPullError
is raised containing details for each error.Assuming the following files exist locally:
/foo/bar/baz.txt
/foo/foobar.txt
/quux.txt
These are various push examples:
# copy one file container.push_path('/foo/foobar.txt', '/dst') # Destination results: /dst/foobar.txt # copy a directory container.push_path('/foo', '/dst') # Destination results: /dst/foo/bar/baz.txt, /dst/foo/foobar.txt # copy a directory's contents container.push_path('/foo/*', '/dst') # Destination results: /dst/bar/baz.txt, /dst/foobar.txt # copy multiple files container.push_path(['/foo/bar/baz.txt', 'quux.txt'], '/dst') # Destination results: /dst/baz.txt, /dst/quux.txt # copy a file and a directory container.push_path(['/foo/bar', '/quux.txt'], '/dst') # Destination results: /dst/bar/baz.txt, /dst/quux.txt
- Parameters:
source_path – A single path or list of paths to push to the remote system. The paths can be either a file or a directory. If
source_path
is a directory, the directory base name is attached to the destination directory – that is, the source path directory is placed inside the destination directory. If a source path ends with a trailing/*
it will have its contents placed inside the destination directory.dest_dir – Remote destination directory inside which the source dir/files will be placed. This must be an absolute path.
- remove_path(path: str | PurePath, *, recursive: bool = False)[source]¶
Remove a file or directory on the remote system.
- Parameters:
path – Path of the file or directory to delete from the remote system.
recursive – If True, recursively delete path and everything under it.
- replan() None [source]¶
Replan all services: restart changed services and start startup-enabled services.
- send_signal(sig: int | str, *service_names: str)[source]¶
Send the given signal to one or more services.
- Parameters:
sig – Name or number of signal to send, for example
"SIGHUP"
,1
, orsignal.SIGHUP
.service_names – Name(s) of the service(s) to send the signal to.
- Raises:
pebble.APIError – If any of the services are not in the plan or are not currently running.
- class ops.ContainerMapping(names: Iterable[str], backend: _ModelBackend)[source]¶
Bases:
Mapping
[str
,Container
]Map of container names to Container objects.
This is done as a mapping object rather than a plain dictionary so that we can extend it later, and so it’s not mutable.
- class ops.ContainerMeta(name: str, raw: Dict[str, Any])[source]¶
Bases:
object
Metadata about an individual container.
NOTE: this is extremely lightweight right now, and just includes the fields we need for Pebble interaction.
- property mounts: Dict[str, ContainerStorageMeta]¶
An accessor for the mounts in a container.
Dict keys match key name in
StorageMeta
Example:
storage: foo: type: filesystem location: /test containers: bar: mounts: - storage: foo - location: /test/mount
- class ops.ContainerStorageMeta(storage: str, location: str)[source]¶
Bases:
object
Metadata about storage for an individual container.
If multiple locations are specified for the same storage, such as Kubernetes subPath mounts,
location
will not be an accessible attribute, as it would not be possible to determine which mount point was desired, andlocations
should be iterated over.- storage: str¶
Name for the mount point, which should exist in the keys of the charm’s
StorageMeta
.
- class ops.ErrorStatus(message: str = '')[source]¶
Bases:
StatusBase
The unit status is error.
The unit-agent has encountered an error (the application or unit requires human intervention in order to operate correctly).
- name = 'error'¶
- class ops.EventBase(handle: Handle)[source]¶
Bases:
object
The base class for all events.
Inherit this and override the
snapshot
andrestore
methods to create a custom event.- defer() None [source]¶
Defer the event to the future.
Deferring an event from a handler puts that handler into a queue, to be called again the next time the charm is invoked. This invocation may be the result of an action, or any event other than metric events. The queue of events will be dispatched before the new event is processed.
Important points that follow from the above:
defer()
does not interrupt the execution of the current event handler. In almost all cases, a call todefer()
should be followed by an explicitreturn
from the handler;the re-execution of the deferred event handler starts from the top of the handler method (not where defer was called);
only the handlers that actually called
defer()
are called again (that is: despite talking about “deferring an event” it is actually the handler/event combination that is deferred); andany deferred events get processed before the event (or action) that caused the current invocation of the charm.
The general desire to call
defer()
happens when some precondition isn’t yet met. However, care should be exercised as to whether it is better to defer this event so that it is seen again, or whether it is better to just wait for the event that indicates the precondition has been met.For example, if handling a config change requires that two config values are changed, there’s no reason to defer the first
config-changed
because there will be a secondconfig-changed
event fired when the other config value changes.Similarly, if two events need to occur before execution can proceed (say event A and B), the event A handler could
defer()
because B has not been seen yet. However, that leads to:event A fires, calls defer()
event B fires, event A handler is called first, still hasn’t seen B happen, so is deferred again. Then B happens, which progresses since it has seen A.
At some future time, event C happens, which also checks if A can proceed.
- class ops.EventSource(event_type: Type[EventBase])[source]¶
Bases:
object
EventSource wraps an event type with a descriptor to facilitate observing and emitting.
It is generally used as:
class SomethingHappened(EventBase): pass class SomeObject(Object): something_happened = EventSource(SomethingHappened)
With that, instances of that type will offer the
someobj.something_happened
attribute which is aBoundEvent
, and may be used to emit and observe the event.
- class ops.Framework(storage: SQLiteStorage | JujuStorage, charm_dir: str | Path, meta: CharmMeta, model: Model, event_name: str | None = None)[source]¶
Bases:
Object
Main interface from the Charm to the ops library’s infrastructure.
- breakpoint(name: str | None = None)[source]¶
Add breakpoint, optionally named, at the place where this method is called.
For the breakpoint to be activated the JUJU_DEBUG_AT environment variable must be set to “all” or to the specific name parameter provided, if any. In every other situation calling this method does nothing.
The framework also provides a standard breakpoint named “hook”, that will stop execution when a hook event is about to be handled.
For those reasons, the “all” and “hook” breakpoint names are reserved.
- charm_dir: pathlib.Path = None¶
The charm project root directory.
- load_snapshot(handle: Handle) Serializable [source]¶
Load a persistent snapshot.
- observe(bound_event: BoundEvent, observer: Callable[[Any], None])[source]¶
Register observer to be called when bound_event is emitted.
If this is called multiple times for the same event type, the framework calls the observers in the order they were observed.
The bound_event is generally provided as an attribute of the object that emits the event, and is created in this style:
class SomeObject: something_happened = Event(SomethingHappened)
That event may be observed as:
framework.observe(someobj.something_happened, self._on_something_happened)
- Raises:
RuntimeError – if bound_event or observer are the wrong type.
- reemit() None [source]¶
Reemit previously deferred events to the observers that deferred them.
Only the specific observers that have previously deferred the event will be notified again. Observers that asked to be notified about events after it’s been first emitted won’t be notified, as that would mean potentially observing events out of order.
- register_type(cls: Type[Serializable], parent: Handle | Object | None, kind: str | None = None)[source]¶
Register a type to a handle.
- remove_unreferenced_events() None [source]¶
Remove events from storage that are not referenced.
In older versions of the framework, events that had no observers would get recorded but never deleted. This makes a best effort to find these events and remove them from the database.
- save_snapshot(value: StoredStateData | EventBase)[source]¶
Save a persistent snapshot of the provided value.
- set_breakpointhook() Any | None [source]¶
Hook into
sys.breakpointhook
so the builtinbreakpoint()
works as expected.This method is called by
main
, and is not intended to be called by users of the framework itself outside of perhaps some testing scenarios.The
breakpoint()
function is a Python >= 3.7 feature.This method was added in ops 1.0; before that, it was done as part of the Framework’s
__init__
.- Returns:
The old value of
sys.breakpointhook
.
- class ops.FrameworkEvents(parent: Object | None = None, key: str | None = None)[source]¶
Bases:
ObjectEvents
Manager of all framework events.
- commit¶
Triggered before event data is committed to storage.
- class ops.Handle(parent: Handle | Object | None, kind: str, key: str | None)[source]¶
Bases:
object
Handle defines a name for an object in the form of a hierarchical path.
The provided parent is the object (or that object’s handle) that this handle sits under, or None if the object identified by this handle stands by itself as the root of its own hierarchy.
The handle kind is a string that defines a namespace so objects with the same parent and kind will have unique keys.
The handle key is a string uniquely identifying the object. No other objects under the same parent and kind may have the same key.
- class ops.HandleKind[source]¶
Bases:
object
Helper descriptor to define the Object.handle_kind field.
The handle_kind for an object defaults to its type name, but it may be explicitly overridden if desired.
- class ops.HookEvent(handle: Handle)[source]¶
Bases:
EventBase
Events raised by Juju to progress a charm’s lifecycle.
Hooks are callback methods of a charm class (a subclass of
CharmBase
) that are invoked in response to events raised by Juju. These callback methods are the means by which a charm governs the lifecycle of its application.The
HookEvent
class is the base of a type hierarchy of events related to the charm’s lifecycle.HookEvent
subtypes are grouped into the following categoriesCore lifecycle events
Relation events
Storage events
Metric events
- class ops.InstallEvent(handle: Handle)[source]¶
Bases:
HookEvent
Event triggered when a charm is installed.
This event is triggered at the beginning of a charm’s lifecycle. Any associated callback method should be used to perform one-time setup operations, such as installing prerequisite software.
- exception ops.InvalidStatusError[source]¶
Bases:
ModelError
Raised if trying to set an Application or Unit status to something invalid.
- class ops.JujuVersion(version: str)[source]¶
Bases:
object
Helper to work with the Juju version.
It knows how to parse the
JUJU_VERSION
environment variable, and exposes different capabilities according to the specific version. It also allows users to compareJujuVersion
instances with<
and>
operators.- classmethod from_environ() JujuVersion [source]¶
Build a version from the
JUJU_VERSION
environment variable.
- has_controller_storage() bool [source]¶
Report whether this Juju version supports controller-side storage.
- class ops.LazyMapping[source]¶
-
Represents a dict that isn’t populated until it is accessed.
Charm authors should generally never need to use this directly, but it forms the basis for many of the dicts that the framework tracks.
- class ops.LeaderElectedEvent(handle: Handle)[source]¶
Bases:
HookEvent
Event triggered when a new leader has been elected.
Juju will trigger this event when a new leader unit is chosen for a given application.
This event fires at least once after Juju selects a leader unit. Callback methods bound to this event may take any action required for the elected unit to assert leadership. Note that only the elected leader unit will receive this event.
- class ops.LeaderSettingsChangedEvent(handle: Handle)[source]¶
Bases:
HookEvent
DEPRECATED. Event triggered when leader changes any settings.
This event has been deprecated in favor of using a Peer relation, and having the leader set a value in the Application data bag for that peer relation. (see
RelationChangedEvent
).
- class ops.LifecycleEvent(handle: Handle)[source]¶
Bases:
EventBase
Events tied to the lifecycle of the Framework object.
- class ops.MaintenanceStatus(message: str = '')[source]¶
Bases:
StatusBase
The unit is performing maintenance tasks.
The unit is not yet providing services, but is actively doing work in preparation for providing those services. This is a “spinning” state, not an error state. It reflects activity on the unit itself, not on peers or related units.
- name = 'maintenance'¶
- class ops.Model(meta: CharmMeta, backend: _ModelBackend)[source]¶
Bases:
object
Represents the Juju Model as seen from this unit.
This should not be instantiated directly by Charmers, but can be accessed as
self.model
from any class that derives fromObject
.- property app: Application¶
The application this unit is a part of.
Use
get_app()
to get an arbitrary application by name.
- property config: ConfigData¶
Return a mapping of config for the current application.
- get_app(app_name: str) Application [source]¶
Get an application by name.
Use
app
to get this charm’s application.Internally this uses a cache, so asking for the same application two times will return the same object.
- get_binding(binding_key: str | Relation) Binding | None [source]¶
Get a network space binding.
- Parameters:
binding_key – The relation name or instance to obtain bindings for.
- Returns:
If
binding_key
is a relation name, the method returns the default binding for that relation. If a relation instance is provided, the method first looks up a more specific binding for that specific relation ID, and if none is found falls back to the default binding for the relation name.
- get_relation(relation_name: str, relation_id: int | None = None) Relation | None [source]¶
Get a specific Relation instance.
If relation_id is not given, this will return the Relation instance if the relation is established only once or None if it is not established. If this same relation is established multiple times the error TooManyRelatedAppsError is raised.
- Parameters:
relation_name – The name of the endpoint for this charm
relation_id – An identifier for a specific relation. Used to disambiguate when a given application has more than one relation on a given endpoint.
- Raises:
TooManyRelatedAppsError – is raised if there is more than one relation to the supplied relation_name and no relation_id was supplied
- get_secret(*, id: str | None = None, label: str | None = None) Secret [source]¶
Get the
Secret
with the given ID or label.The caller must provide at least one of id (the secret’s locator ID) or label (the charm-local “name”).
If both are provided, the secret will be fetched by ID, and the secret’s label will be updated to the label provided. Normally secret owners set a label using
add_secret
, whereas secret observers set a label usingget_secret
(see an example atSecret.label
).- Parameters:
id – Secret ID if fetching by ID.
label – Secret label if fetching by label (or updating it).
- Raises:
SecretNotFoundError – If a secret with this ID or label doesn’t exist.
- get_unit(unit_name: str) Unit [source]¶
Get an arbitrary unit by name.
Use
unit
to get the current unit.Internally this uses a cache, so asking for the same unit two times will return the same object.
- property name: str¶
Return the name of the Model that this unit is running in.
This is read from the environment variable
JUJU_MODEL_NAME
.
- property pod: Pod¶
Represents the definition of a pod spec in legacy Kubernetes models.
DEPRECATED: New charms should use the sidecar pattern with Pebble.
Use
Pod.set_spec()
to set the container specification for legacy Kubernetes charms.
- property relations: RelationMapping¶
Mapping of endpoint to list of
Relation
.Answers the question “what am I currently related to”. See also
get_relation()
.
- property resources: Resources¶
Access to resources for this charm.
Use
model.resources.fetch(resource_name)
to get the path on disk where the resource can be found.
- property storages: StorageMapping¶
Mapping of storage_name to
Storage
as defined in metadata.yaml.
- property unit: Unit¶
The unit that is running this code.
Use
get_unit()
to get an arbitrary unit by name.
- exception ops.ModelError[source]¶
Bases:
Exception
Base class for exceptions raised when interacting with the Model.
- exception ops.MultiPushPullError(message: str, errors: List[Tuple[str, Exception]])[source]¶
Bases:
Exception
Aggregates multiple push and pull exceptions into one.
This class should not be instantiated directly. It is raised by
Container.push_path()
andContainer.pull_path()
.
- class ops.Network(network_info: _NetworkDict)[source]¶
Bases:
object
Network space details.
Charm authors should not instantiate this directly, but should get access to the Network definition from
Model.get_binding()
and itsnetwork
attribute.- property bind_address: IPv4Address | IPv6Address | str | None¶
A single address that the charm’s application should bind() to.
For the common case where there is a single answer. This represents a single address from
interfaces
that can be used to configure where the charm’s application should bind() and listen().
- egress_subnets: List[IPv4Network | IPv6Network]¶
A list of networks representing the subnets that other units will see the charm connecting from. Due to things like NAT it isn’t always possible to narrow it down to a single address, but when it is clear, the CIDRs will be constrained to a single address (for example, 10.0.0.1/32).
- property ingress_address: IPv4Address | IPv6Address | str | None¶
The address other applications should use to connect to the current unit.
Due to things like public/private addresses, NAT and tunneling, the address the charm will bind() to is not always the address other people can use to connect() to the charm. This is just the first address from
ingress_addresses
.
- ingress_addresses: List[IPv4Address | IPv6Address | str]¶
A list of IP addresses that other units should use to get in touch with the charm.
- interfaces: List[NetworkInterface]¶
A list of network interface details. This includes the information about how the application should be configured (for example, what IP addresses should be bound to).
Multiple addresses for a single interface are represented as multiple interfaces, for example:
[NetworkInfo('ens1', '10.1.1.1/32'), NetworkInfo('ens1', '10.1.2.1/32'])
- class ops.NetworkInterface(name: str, address_info: _AddressDict)[source]¶
Bases:
object
Represents a single network interface that the charm needs to know about.
Charmers should not instantiate this type directly. Instead use
Model.get_binding()
to get the network information for a given endpoint.- address: IPv4Address | IPv6Address | str | None¶
The address of the network interface.
- subnet: IPv4Network | IPv6Network | None¶
The subnet of the network interface. This may be a single address (for example, ‘10.0.1.2/32’).
- exception ops.NoTypeError(handle_path: str)[source]¶
Bases:
Exception
No class to hold it was found when restoring an event.
- class ops.Object(parent: Framework | Object, key: str | None)[source]¶
Bases:
object
Initialize an Object as a new leaf in
Framework
, identified by key.- Parameters:
parent – parent node in the tree.
key – unique identifier for this object.
Every object belongs to exactly one framework.
Every object has a parent, which might be a framework.
We track a “path to object,” which is the path to the parent, plus the object’s unique identifier. Event handlers use this identity to track the destination of their events, and the Framework uses this id to track persisted state between event executions.
The Framework should raise an error if it ever detects that two objects with the same id have been created.
- class ops.ObjectEvents(parent: Object | None = None, key: str | None = None)[source]¶
Bases:
Object
Convenience type to allow defining
.on
attributes at class level.- classmethod define_event(event_kind: str, event_type: Type[EventBase])[source]¶
Define an event on this type at runtime.
Note that attempting to define the same event kind more than once will raise an “overlaps with existing type” runtime error. Ops uses a labeling system to track and reconstruct events between hook executions (each time a hook runs, the Juju Agent invokes a fresh instance of ops; there is no ops process that persists on the host between hooks). Having duplicate Python objects creates duplicate labels. Overwriting a previously created label means that only the latter code path will be run when the current event, if it does get deferred, is re-emitted. This is usually not what is desired, and is error-prone and ambiguous.
- Parameters:
event_kind – An attribute name that will be used to access the event. Must be a valid Python identifier, not be a keyword or an existing attribute.
event_type – A type of the event to define.
- events() Dict[str, EventSource] [source]¶
Return a mapping of event_kinds to bound_events for all available events.
- class ops.PayloadMeta(name: str, raw: Dict[str, Any])[source]¶
Bases:
object
Object containing metadata about a payload definition.
- class ops.PebbleReadyEvent(handle: Handle, workload: Container)[source]¶
Bases:
WorkloadEvent
Event triggered when pebble is ready for a workload.
This event is triggered when the Pebble process for a workload/container starts up, allowing the charm to configure how services should be launched.
Callback methods bound to this event allow the charm to run code after a workload has started its Pebble instance and is ready to receive instructions regarding what services should be started. The name prefix of the hook will depend on the container key defined in the
metadata.yaml
file.
- class ops.Pod(backend: _ModelBackend)[source]¶
Bases:
object
Represents the definition of a pod spec in legacy Kubernetes models.
DEPRECATED: New charms should use the sidecar pattern with Pebble.
Currently only supports simple access to setting the Juju pod spec via
set_spec
.- set_spec(spec: Mapping[str, Any], k8s_resources: Mapping[str, Any] | None = None)[source]¶
Set the specification for pods that Juju should start in kubernetes.
See
juju help-tool pod-spec-set
for details of what should be passed.- Parameters:
spec – The mapping defining the pod specification
k8s_resources – Additional kubernetes specific specification.
- class ops.Port(protocol: Literal['tcp', 'udp', 'icmp'], port: int | None)[source]¶
Bases:
object
Represents a port opened by
Unit.open_port()
orUnit.set_ports()
.
- class ops.PostSeriesUpgradeEvent(handle: Handle)[source]¶
Bases:
HookEvent
Event triggered after a series upgrade.
This event is triggered after the administrator has done a distribution upgrade (or rolled back and kept the same series). It is called in response to
juju upgrade-machine <machine> complete
. Associated charm callback methods are expected to do whatever steps are necessary to reconfigure their applications for the new series. This may include things like populating the upgraded version of a database. Note however charms are expected to check if the series has actually changed or whether it was rolled back to the original series.
- class ops.PreCommitEvent(handle: Handle)[source]¶
Bases:
LifecycleEvent
Event that will be emitted first on commit.
- class ops.PreSeriesUpgradeEvent(handle: Handle)[source]¶
Bases:
HookEvent
Event triggered to prepare a unit for series upgrade.
This event triggers when an administrator executes
juju upgrade-machine <machine> prepare
. The event will fire for each unit that is running on the specified machine. Any callback method bound to this event must prepare the charm for an upgrade to the series. This may include things like exporting database content to a version neutral format, or evacuating running instances to other machines.It can be assumed that only after all units on a machine have executed the callback method associated with this event, the administrator will initiate steps to actually upgrade the series. After the upgrade has been completed, the
PostSeriesUpgradeEvent
will fire.
- class ops.PrefixedEvents(emitter: Object, key: str)[source]¶
Bases:
object
Events to be found in all events using a specific prefix.
- class ops.Relation(relation_name: str, relation_id: int, is_peer: bool, our_unit: Unit, backend: _ModelBackend, cache: _ModelCache)[source]¶
Bases:
object
Represents an established relation between this application and another application.
This class should not be instantiated directly, instead use
Model.get_relation()
,Model.relations
, orops.RelationEvent.relation
. This is principally used byops.RelationMeta
to represent the relationships between charms.- app: Application | None¶
Represents the remote application of this relation.
For peer relations, this will be the local application.
- data: RelationData¶
Holds the data buckets for each entity of a relation.
This is accessed using, for example,
Relation.data[unit]['foo']
.
- class ops.RelationBrokenEvent(handle: Handle, relation: Relation, app: Application | None = None, unit: Unit | None = None)[source]¶
Bases:
RelationEvent
Event triggered when a relation is removed.
If a relation is being removed (
juju remove-relation
orjuju remove-application
), once all the units have been removed, this event will fire to signal that the relationship has been fully terminated.The event indicates that the current relation is no longer valid, and that the charm’s software must be configured as though the relation had never existed. It will only be called after every callback method bound to
RelationDepartedEvent
has been run. If a callback method bound to this event is being executed, it is guaranteed that no remote units are currently known locally.
- class ops.RelationChangedEvent(handle: Handle, relation: Relation, app: Application | None = None, unit: Unit | None = None)[source]¶
Bases:
RelationEvent
Event triggered when relation data changes.
This event is triggered whenever there is a change to the data bucket for a related application or unit. Look at
event.relation.data[event.unit/app]
to see the new information, whereevent
is the event object passed to the callback method bound to this event.This event always fires once, after
RelationJoinedEvent
, and will subsequently fire whenever that remote unit changes its settings for the relation. Callback methods bound to this event should be the only ones that rely on remote relation settings. They should not error if the settings are incomplete, since it can be guaranteed that when the remote unit or application changes its settings, the event will fire again.The settings that may be queried, or set, are determined by the relation’s interface.
- class ops.RelationCreatedEvent(handle: Handle, relation: Relation, app: Application | None = None, unit: Unit | None = None)[source]¶
Bases:
RelationEvent
Event triggered when a new relation is created.
This is triggered when a new relation to another app is added in Juju. This can occur before units for those applications have started. All existing relations should be established before start.
- class ops.RelationData(relation: Relation, our_unit: Unit, backend: _ModelBackend)[source]¶
Bases:
Mapping
[Union
[Unit
,Application
],RelationDataContent
]Represents the various data buckets of a given relation.
Each unit and application involved in a relation has their own data bucket. For example,
{entity: RelationDataContent}
, where entity can be either aUnit
or anApplication
.Units can read and write their own data, and if they are the leader, they can read and write their application data. They are allowed to read remote unit and application data.
This class should not be instantiated directly, instead use
Relation.data
- exception ops.RelationDataAccessError[source]¶
Bases:
RelationDataError
Raised by
Relation.data[entity][key] = value
if unable to access.This typically means that permission to write read/write the databag is missing, but in some cases it is raised when attempting to read/write from a deceased remote entity.
- class ops.RelationDataContent(relation: Relation, entity: Unit | Application, backend: _ModelBackend)[source]¶
Bases:
LazyMapping
,MutableMapping
[str
,str
]Data content of a unit or application in a relation.
- exception ops.RelationDataError[source]¶
Bases:
ModelError
Raised when a relation data read/write is invalid.
This is raised either when trying to set a value to something that isn’t a string, or when trying to set a value in a bucket without the required access. (For example, another application/unit, or setting application data without being the leader.)
- exception ops.RelationDataTypeError[source]¶
Bases:
RelationDataError
Raised by
Relation.data[entity][key] = value
if key or value are not strings.
- class ops.RelationDepartedEvent(handle: Handle, relation: Relation, app: Application | None = None, unit: Unit | None = None, departing_unit_name: str | None = None)[source]¶
Bases:
RelationEvent
Event triggered when a unit leaves a relation.
This is the inverse of the
RelationJoinedEvent
, representing when a unit is leaving the relation (the unit is being removed, the app is being removed, the relation is being removed). For remaining units, this event is emitted once for each departing unit. For departing units, this event is emitted once for each remaining unit.Callback methods bound to this event may be used to remove all references to the departing remote unit, because there’s no guarantee that it’s still part of the system; it’s perfectly probable (although not guaranteed) that the system running that unit has already shut down.
Once all callback methods bound to this event have been run for such a relation, the unit agent will fire the
RelationBrokenEvent
.- property departing_unit: Unit | None¶
The
ops.Unit
that is departing, if any.Use this method to determine (for example) whether this unit is the departing one.
- class ops.RelationEvent(handle: Handle, relation: Relation, app: Application | None = None, unit: Unit | None = None)[source]¶
Bases:
HookEvent
A base class representing the various relation lifecycle events.
Relation lifecycle events are generated when application units participate in relations. Units can only participate in relations after they have been “started”, and before they have been “stopped”. Within that time window, the unit may participate in several different relations at a time, including multiple relations with the same name.
- app: Application | None¶
The remote application that has triggered this event.
- restore(snapshot: Dict[str, Any])[source]¶
Used by the framework to deserialize the event from disk.
Not meant to be called by charm code.
- snapshot() Dict[str, Any] [source]¶
Used by the framework to serialize the event to disk.
Not meant to be called by charm code.
- unit: Unit | None¶
The remote unit that has triggered this event.
This will be
None
if the relation event was triggered as anApplication
-level event.
- class ops.RelationJoinedEvent(handle: Handle, relation: Relation, app: Application | None = None, unit: Unit | None = None)[source]¶
Bases:
RelationEvent
Event triggered when a new unit joins a relation.
This event is triggered whenever a new unit of a related application joins the relation. The event fires only when that remote unit is first observed by the unit. Callback methods bound to this event may set any local unit settings that can be determined using no more than the name of the joining unit and the remote
private-address
setting, which is always available when the relation is created and is by convention not deleted.
- class ops.RelationMapping(relations_meta: Dict[str, RelationMeta], our_unit: Unit, backend: _ModelBackend, cache: _ModelCache)[source]¶
Bases:
Mapping
[str
,List
[Relation
]]Map of relation names to lists of
Relation
instances.
- class ops.RelationMeta(role: RelationRole, relation_name: str, raw: _RelationMetaDict)[source]¶
Bases:
object
Object containing metadata about a relation definition.
Should not be constructed directly by charm code, but gotten from one of
CharmMeta.peers
,CharmMeta.requires
,CharmMeta.provides
, orCharmMeta.relations
.- VALID_SCOPES = ['global', 'container']¶
- role: RelationRole¶
Role this relation takes, one of ‘peer’, ‘requires’, or ‘provides’.
- exception ops.RelationNotFoundError[source]¶
Bases:
ModelError
Raised when querying Juju for a given relation and that relation doesn’t exist.
- class ops.RelationRole(value, names=None, *, module=None, qualname=None, type=None, start=1, boundary=None)[source]¶
Bases:
Enum
An annotation for a charm’s role in a relation.
For each relation a charm’s role may be
A Peer
A service consumer in the relation (‘requires’)
A service provider in the relation (‘provides’)
- is_peer() bool [source]¶
Report whether this role is ‘peer’.
role.is_peer()
is a shortcut forrole == ops.RelationRole.peer
.
- peer = 'peer'¶
- provides = 'provides'¶
- requires = 'requires'¶
- class ops.RemoveEvent(handle: Handle)[source]¶
Bases:
HookEvent
Event triggered when a unit is about to be terminated.
This event fires prior to Juju removing the charm and terminating its unit.
- class ops.ResourceMeta(name: str, raw: _ResourceMetaDict)[source]¶
Bases:
object
Object containing metadata about a resource definition.
- class ops.Resources(names: Iterable[str], backend: _ModelBackend)[source]¶
Bases:
object
Object representing resources for the charm.
- class ops.Secret(backend: _ModelBackend, id: str | None = None, label: str | None = None, content: Dict[str, str] | None = None)[source]¶
Bases:
object
Represents a single secret in the model.
This class should not be instantiated directly, instead use
Model.get_secret()
(for observers and owners), orApplication.add_secret()
orUnit.add_secret()
(for owners).All secret events have a
.secret
attribute which provides theSecret
associated with that event.- get_content(*, refresh: bool = False) Dict[str, str] [source]¶
Get the secret’s content.
- Returns:
A copy of the secret’s content dictionary.
- Parameters:
refresh – If true, fetch the latest revision’s content and tell Juju to update to tracking that revision. The default is to get the content of the currently-tracked revision. This parameter is only meaningful for secret observers, not owners.
- get_info() SecretInfo [source]¶
Get this secret’s information (metadata).
Only secret owners can fetch this information.
- grant(relation: Relation, *, unit: Unit | None = None)[source]¶
Grant read access to this secret.
If the application or unit has already been granted access to this secret, do nothing.
- Parameters:
relation – The relation used to scope the life of this secret.
unit – If specified, grant access to only this unit, rather than all units in the application.
- property id: str | None¶
Locator ID (URI) for this secret.
This has an unfortunate name for historical reasons, as it’s not really a unique identifier, but the secret’s locator URI, which may or may not include the model UUID (for cross-model secrets).
Charms should treat this as an opaque string for looking up secrets and sharing them via relation data. If a charm-local “name” is needed for a secret, use a
label
. (If a charm needs a truly unique identifier for identifying one secret in a set of secrets of arbitrary size, useunique_identifier
– this should be rare.)This will be None if the secret was obtained using
Model.get_secret()
with a label but no ID.
- property label: str | None¶
Label used to reference this secret locally.
This label is effectively a name for the secret that’s local to the charm, for example “db-password” or “tls-cert”. The secret owner sets a label with
Application.add_secret()
orUnit.add_secret()
, and the secret observer sets a label with a call toModel.get_secret()
.The label property can be used distinguish between multiple secrets in event handlers like
ops.SecretChangedEvent
. For example, if a charm is observing two secrets, it might callmodel.get_secret(id=secret_id, label='db-password')
andmodel.get_secret(id=secret_id, label='tls-cert')
in the relevant relation-changed event handlers, and then switch onevent.secret.label
in secret-changed:def _on_secret_changed(self, event): if event.secret.label == 'db-password': content = event.secret.get_content(refresh=True) self._configure_db_credentials(content['username'], content['password']) elif event.secret.label == 'tls-cert': content = event.secret.get_content(refresh=True) self._update_tls_cert(content['cert']) else: pass # ignore other labels (or log a warning)
Juju will ensure that the entity (the owner or observer) only has one secret with this label at once.
This will be None if the secret was obtained using
Model.get_secret()
with an ID but no label.
- peek_content() Dict[str, str] [source]¶
Get the content of the latest revision of this secret.
This returns the content of the latest revision without updating the tracking.
- remove_all_revisions() None [source]¶
Remove all revisions of this secret.
This is called when the secret is no longer needed, for example when handling
ops.RelationBrokenEvent
.
- remove_revision(revision: int)[source]¶
Remove the given secret revision.
This is normally called when handling
ops.SecretRemoveEvent
orops.SecretExpiredEvent
.- Parameters:
revision – The secret revision to remove. If being called from a secret event, this should usually be set to
SecretRemoveEvent.revision
.
- revoke(relation: Relation, *, unit: Unit | None = None)[source]¶
Revoke read access to this secret.
If the application or unit does not have access to this secret, do nothing.
- Parameters:
relation – The relation used to scope the life of this secret.
unit – If specified, revoke access to only this unit, rather than all units in the application.
- set_content(content: Dict[str, str])[source]¶
Update the content of this secret.
This will create a new secret revision, and notify all units tracking the secret (the “observers”) that a new revision is available with a
ops.SecretChangedEvent
.- Parameters:
content – A key-value mapping containing the payload of the secret, for example
{"password": "foo123"}
.
- set_info(*, label: str | None = None, description: str | None = None, expire: datetime | timedelta | None = None, rotate: SecretRotate | None = None)[source]¶
Update this secret’s information (metadata).
This will not create a new secret revision (that applies only to
set_content()
). Once attributes are set, they cannot be unset.- Parameters:
label – New label to apply.
description – New description to apply.
expire – New expiration time (or timedelta from now) to apply.
rotate – New rotation policy to apply. The new policy will take effect only after the currently-scheduled rotation.
- property unique_identifier: str | None¶
Unique identifier of this secret.
This is the secret’s globally-unique identifier (currently a 20-character Xid, for example “9m4e2mr0ui3e8a215n4g”).
Charms should use
id
(the secret’s locator ID) to send the secret’s ID across relation data, and labels (label
) to assign a charm-local “name” to the secret for lookup in this charm. However,unique_identifier
can be useful to distinguish secrets in cases where the charm has a set of secrets of arbitrary size, for example, a group of 10 or 20 TLS certificates.This will be None if the secret was obtained using
Model.get_secret()
with a label but no ID.
- class ops.SecretChangedEvent(handle: Handle, id: str, label: str | None)[source]¶
Bases:
SecretEvent
Event triggered on the secret observer charm when the secret owner changes its contents.
When the owner of a secret changes the secret’s contents, Juju will create a new secret revision, and all applications or units that are tracking this secret will be notified via this event that a new revision is available.
Typically, the charm will fetch the new content by calling
event.secret.get_content()
withrefresh=True
to tell Juju to start tracking the new revision.
- class ops.SecretEvent(handle: Handle, id: str, label: str | None)[source]¶
Bases:
HookEvent
Base class for all secret events.
- class ops.SecretExpiredEvent(handle: Handle, id: str, label: str | None, revision: int)[source]¶
Bases:
SecretEvent
Event triggered on the secret owner charm when a secret’s expiration time elapses.
This event is fired on the secret owner to inform it that the secret revision must be removed. The event will keep firing until the owner removes the revision by calling
event.secret.remove_revision()
.
- class ops.SecretInfo(id: str, label: str | None, revision: int, expires: datetime | None, rotation: SecretRotate | None, rotates: datetime | None)[source]¶
Bases:
object
Secret information (metadata).
- exception ops.SecretNotFoundError[source]¶
Bases:
ModelError
Raised when the specified secret does not exist.
- class ops.SecretRemoveEvent(handle: Handle, id: str, label: str | None, revision: int)[source]¶
Bases:
SecretEvent
Event triggered on the secret owner charm when a secret revision can be removed.
When the owner of a secret creates a new revision, and after all observers have updated to that new revision, this event will be fired to inform the secret owner that the old revision can be removed.
Typically, the charm will call
event.secret.remove_revision()
to remove the now-unused revision.
- class ops.SecretRotate(value, names=None, *, module=None, qualname=None, type=None, start=1, boundary=None)[source]¶
Bases:
Enum
Secret rotation policies.
- DAILY = 'daily'¶
- HOURLY = 'hourly'¶
- MONTHLY = 'monthly'¶
- NEVER = 'never'¶
- QUARTERLY = 'quarterly'¶
- WEEKLY = 'weekly'¶
- YEARLY = 'yearly'¶
- class ops.SecretRotateEvent(handle: Handle, id: str, label: str | None)[source]¶
Bases:
SecretEvent
Event triggered on the secret owner charm when the secret’s rotation policy elapses.
This event is fired on the secret owner to inform it that the secret must be rotated. The event will keep firing until the owner creates a new revision by calling
event.secret.set_content()
.
- class ops.Serializable(*args, **kwargs)[source]¶
Bases:
Protocol
The type returned by
Framework.load_snapshot()
.- handle_kind = ''¶
- class ops.ServiceInfoMapping(services: Iterable[ServiceInfo])[source]¶
Bases:
Mapping
[str
,ServiceInfo
]Map of service names to
pebble.ServiceInfo
objects.This is done as a mapping object rather than a plain dictionary so that we can extend it later, and so it’s not mutable.
- class ops.StartEvent(handle: Handle)[source]¶
Bases:
HookEvent
Event triggered immediately after first configuration change.
This event is triggered immediately after the first
ConfigChangedEvent
. Callback methods bound to the event should be used to ensure that the charm’s software is in a running state. Note that the charm’s software should be configured so as to persist in this state through reboots without further intervention on Juju’s part.
- class ops.StatusBase(message: str = '')[source]¶
Bases:
object
Status values specific to applications and units.
To access a status by name, use
StatusBase.from_name()
. However, most use cases will directly use the child class such asActiveStatus
to indicate their status.- classmethod from_name(name: str, message: str)[source]¶
Create a status instance from a name and message.
If
name
is “unknown”,message
is ignored, because unknown status does not have an associated message.- Parameters:
name – Name of the status, for example “active” or “blocked”.
message – Message to include with the status.
- Raises:
KeyError – If
name
is not a registered status.
- name = ''¶
- classmethod register(child: Type[StatusBase])[source]¶
Register a Status for the child’s name.
- class ops.StopEvent(handle: Handle)[source]¶
Bases:
HookEvent
Event triggered when a charm is shut down.
This event is triggered when an application’s removal is requested by the client. The event fires immediately before the end of the unit’s destruction sequence. Callback methods bound to this event should be used to ensure that the charm’s software is not running, and that it will not start again on reboot.
- class ops.Storage(storage_name: str, storage_index: int, backend: _ModelBackend)[source]¶
Bases:
object
Represents a storage as defined in
metadata.yaml
.- property id: int¶
DEPRECATED. Use
Storage.index
instead.
- class ops.StorageAttachedEvent(handle: Handle, storage: Storage)[source]¶
Bases:
StorageEvent
Event triggered when new storage becomes available.
This event is triggered when new storage is available for the charm to use.
Callback methods bound to this event allow the charm to run code when storage has been added. Such methods will be run before the
InstallEvent
fires, so that the installation routine may use the storage. The name prefix of this hook will depend on the storage key defined in themetadata.yaml
file.
- class ops.StorageDetachingEvent(handle: Handle, storage: Storage)[source]¶
Bases:
StorageEvent
Event triggered prior to removal of storage.
This event is triggered when storage a charm has been using is going away.
Callback methods bound to this event allow the charm to run code before storage is removed. Such methods will be run before storage is detached, and always before the
StopEvent
fires, thereby allowing the charm to gracefully release resources before they are removed and before the unit terminates. The name prefix of the hook will depend on the storage key defined in themetadata.yaml
file.
- class ops.StorageEvent(handle: Handle, storage: Storage)[source]¶
Bases:
HookEvent
Base class representing storage-related events.
Juju can provide a variety of storage types to a charms. The charms can define several different types of storage that are allocated from Juju. Changes in state of storage trigger sub-types of
StorageEvent
.- restore(snapshot: Dict[str, Any])[source]¶
Used by the framework to deserialize the event from disk.
Not meant to be called by charm code.
- class ops.StorageMapping(storage_names: Iterable[str], backend: _ModelBackend)[source]¶
Bases:
Mapping
[str
,List
[Storage
]]Map of storage names to lists of Storage instances.
- class ops.StorageMeta(name: str, raw: _StorageMetaDict)[source]¶
Bases:
object
Object containing metadata about a storage definition.
- multiple_range: Tuple[int, int | None] | None¶
Range of numeric qualifiers when multiple storage units are used.
True if all units of the application share the storage.
- class ops.StoredDict(stored_data: StoredStateData, under: Dict[Hashable, Any])[source]¶
Bases:
MutableMapping
[Hashable
,Any
]A dict-like object that uses the StoredState as backend.
- class ops.StoredList(stored_data: StoredStateData, under: List[Any])[source]¶
Bases:
MutableSequence
[Any
]A list-like object that uses the StoredState as backend.
- class ops.StoredSet(stored_data: StoredStateData, under: Set[Any])[source]¶
Bases:
MutableSet
[Any
]A set-like object that uses the StoredState as backend.
- class ops.StoredState[source]¶
Bases:
object
A class used to store data the charm needs, persisted across invocations.
Example:
class MyClass(Object): _stored = StoredState()
Instances of
MyClass
can transparently save state between invocations by setting attributes on_stored
. Initial state should be set withset_default
on the bound object, that is:class MyClass(Object): _stored = StoredState() def __init__(self, parent, key): super().__init__(parent, key) self._stored.set_default(seen=set()) self.framework.observe(self.on.seen, self._on_seen) def _on_seen(self, event): self._stored.seen.add(event.uuid)
- class ops.StoredStateData(parent: Object, attr_name: str)[source]¶
Bases:
Object
Manager of the stored data.
- exception ops.TooManyRelatedAppsError(relation_name: str, num_related: int, max_supported: int)[source]¶
Bases:
ModelError
Raised by
Model.get_relation()
if there is more than one related application.
- class ops.Unit(name: str, meta: CharmMeta, backend: _ModelBackend, cache: _ModelCache)[source]¶
Bases:
object
Represents a named unit in the model.
This might be the current unit, another unit of the charm’s application, or a unit of another application that the charm is related to.
- add_secret(content: Dict[str, str], *, label: str | None = None, description: str | None = None, expire: datetime | timedelta | None = None, rotate: SecretRotate | None = None) Secret [source]¶
Create a
Secret
owned by this unit.See
Application.add_secret()
for parameter details.
- app: Application¶
Application the unit is part of.
- close_port(protocol: Literal['tcp', 'udp', 'icmp'], port: int | None = None) None [source]¶
Close a port with the given protocol for this unit.
Some behaviour, such as whether the port is closed externally without using “juju unexpose”, differs between Kubernetes and machine charms. See the Juju documentation for more detail.
Use
set_ports()
for a more declarative approach where all of the ports that should be open are provided in a single call. For example,set_ports()
will close all open ports.- Parameters:
protocol – String representing the protocol; must be one of ‘tcp’, ‘udp’, or ‘icmp’ (lowercase is recommended, but uppercase is also supported).
port – The port to open. Required for TCP and UDP; not allowed for ICMP.
- Raises:
ModelError – If
port
is provided whenprotocol
is ‘icmp’ orport
is not provided whenprotocol
is ‘tcp’ or ‘udp’.
- get_container(container_name: str) Container [source]¶
Get a single container by name.
- Raises:
ModelError – if the named container doesn’t exist
- is_leader() bool [source]¶
Return whether this unit is the leader of its application.
This can only be called for the current unit.
- Raises:
RuntimeError – if called for another unit
- open_port(protocol: Literal['tcp', 'udp', 'icmp'], port: int | None = None) None [source]¶
Open a port with the given protocol for this unit.
Some behaviour, such as whether the port is opened externally without using “juju expose” and whether the opened ports are per-unit, differs between Kubernetes and machine charms. See the Juju documentation for more detail.
Use
set_ports()
for a more declarative approach where all of the ports that should be open are provided in a single call.- Parameters:
protocol – String representing the protocol; must be one of ‘tcp’, ‘udp’, or ‘icmp’ (lowercase is recommended, but uppercase is also supported).
port – The port to open. Required for TCP and UDP; not allowed for ICMP.
- Raises:
ModelError – If
port
is provided whenprotocol
is ‘icmp’ orport
is not provided whenprotocol
is ‘tcp’ or ‘udp’.
- set_ports(*ports: int | Port) None [source]¶
Set the open ports for this unit, closing any others that are open.
Some behaviour, such as whether the port is opened or closed externally without using Juju’s
expose
andunexpose
commands, differs between Kubernetes and machine charms. See the Juju documentation for more detail.Use
open_port()
andclose_port()
to manage ports individually.- Parameters:
ports – The ports to open. Provide an int to open a TCP port, or a
Port
to open a port for another protocol.
- set_workload_version(version: str) None [source]¶
Record the version of the software running as the workload.
This shouldn’t be confused with the revision of the charm. This is informative only; shown in the output of ‘juju status’.
- property status: StatusBase¶
Used to report or read the status of a specific unit.
Changes to status take effect immediately, unlike other Juju operations such as modifying relation data or secrets, which only take effect after a successful event.
The status of any unit other than the current unit is always Unknown.
Alternatively, use the
collect_unit_status
event to evaluate and set unit status consistently at the end of every hook.- Raises:
RuntimeError – if setting the status of a unit other than the current unit
InvalidStatusError – if setting the status to something other than a
StatusBase
Example:
self.model.unit.status = MaintenanceStatus('reconfiguring the frobnicators')
- class ops.UnknownStatus[source]¶
Bases:
StatusBase
The unit status is unknown.
A unit-agent has finished calling install, config-changed and start, but the charm has not called status-set yet.
- name = 'unknown'¶
- class ops.UpdateStatusEvent(handle: Handle)[source]¶
Bases:
HookEvent
Event triggered by a status update request from Juju.
This event is periodically triggered by Juju so that it can provide constant feedback to the administrator about the status of the application the charm is modeling. Any callback method bound to this event should determine the “health” of the application and set the status appropriately.
The interval between
update-status
events can be configured model-wide, e.g.juju model-config update-status-hook-interval=1m
.
- class ops.UpgradeCharmEvent(handle: Handle)[source]¶
Bases:
HookEvent
Event triggered by request to upgrade the charm.
This event will be triggered when an administrator executes
juju upgrade-charm
. The event fires after Juju has unpacked the upgraded charm code, and so this event will be handled by the callback method bound to the event in the new codebase. The associated callback method is invoked provided there is no existing error state. The callback method should be used to reconcile current state written by an older version of the charm into whatever form that is needed by the current charm version.
- class ops.WaitingStatus(message: str = '')[source]¶
Bases:
StatusBase
A unit is unable to progress.
The unit is unable to progress to an active state because an application to which it is related is not running.
- name = 'waiting'¶
- class ops.WorkloadEvent(handle: Handle, workload: Container)[source]¶
Bases:
HookEvent
Base class representing workload-related events.
Workload events are generated for all containers that the charm expects in metadata. Workload containers currently only trigger a
PebbleReadyEvent
.- restore(snapshot: Dict[str, Any])[source]¶
Used by the framework to deserialize the event from disk.
Not meant to be called by charm code.
ops.pebble module¶
Client for the Pebble API (HTTP over Unix socket).
For a command-line interface for local testing, see test/pebble_cli.py.
- exception ops.pebble.APIError(body: Dict[str, Any], code: int, status: str, message: str)[source]¶
Bases:
Error
Raised when an HTTP API error occurs talking to the Pebble server.
- class ops.pebble.Change(id: ChangeID, kind: str, summary: str, status: str, tasks: List[Task], ready: bool, err: str | None, spawn_time: datetime, ready_time: datetime | None, data: Dict[str, Any] | None = None)[source]¶
Bases:
object
Change object.
- exception ops.pebble.ChangeError(err: str, change: Change)[source]¶
Bases:
Error
Raised by actions when a change is ready but has an error.
- class ops.pebble.ChangeState(value, names=None, *, module=None, qualname=None, type=None, start=1, boundary=None)[source]¶
Bases:
Enum
Enum of states for get_changes() select parameter.
- ALL = 'all'¶
- IN_PROGRESS = 'in-progress'¶
- READY = 'ready'¶
- class ops.pebble.Check(name: str, raw: CheckDict | None = None)[source]¶
Bases:
object
Represents a check in a Pebble configuration layer.
- class ops.pebble.CheckDict¶
Bases:
dict
- level: CheckLevel | str¶
- class ops.pebble.CheckInfo(name: str, level: CheckLevel | str | None, status: CheckStatus | str, failures: int = 0, threshold: int = 0)[source]¶
Bases:
object
Check status information.
A list of these objects is returned from
Client.get_checks()
.- failures: int¶
Number of failures since the check last succeeded.
This is reset to zero if the check succeeds.
- classmethod from_dict(d: _CheckInfoDict) CheckInfo [source]¶
Create new
CheckInfo
object from dict parsed from JSON.
- level: CheckLevel | str | None¶
Check level.
This can be
CheckLevel.ALIVE
,CheckLevel.READY
, or None (level not set).
- status: CheckStatus | str¶
Status of the check.
CheckStatus.UP
means the check is healthy (the number of failures is less than the threshold),CheckStatus.DOWN
means the check is unhealthy (the number of failures has reached the threshold).
- class ops.pebble.CheckLevel(value, names=None, *, module=None, qualname=None, type=None, start=1, boundary=None)[source]¶
Bases:
Enum
Enum of check levels.
- ALIVE = 'alive'¶
- READY = 'ready'¶
- UNSET = ''¶
- class ops.pebble.CheckStatus(value, names=None, *, module=None, qualname=None, type=None, start=1, boundary=None)[source]¶
Bases:
Enum
Enum of check statuses.
- DOWN = 'down'¶
- UP = 'up'¶
- class ops.pebble.Client(socket_path: str, opener: OpenerDirector | None = None, base_url: str = 'http://localhost', timeout: float = 5.0)[source]¶
Bases:
object
Pebble API client.
Defaults to using a Unix socket at socket_path (which must be specified unless a custom opener is provided).
- ack_warnings(timestamp: datetime) int [source]¶
Acknowledge warnings up to given timestamp, return number acknowledged.
- add_layer(label: str, layer: str | LayerDict | Layer, *, combine: bool = False)[source]¶
Dynamically add a new layer onto the Pebble configuration layers.
If combine is False (the default), append the new layer as the top layer with the given label. If combine is True and the label already exists, the two layers are combined into a single one considering the layer override rules; if the layer doesn’t exist, it is added as usual.
- autostart_services(timeout: float = 30.0, delay: float = 0.1) ChangeID [source]¶
Start the startup-enabled services and wait (poll) for them to be started.
- Parameters:
timeout – Seconds before autostart change is considered timed out (float).
delay – Seconds before executing the autostart change (float).
- Returns:
ChangeID of the autostart change.
- Raises:
ChangeError – if one or more of the services didn’t start. If timeout is 0, submit the action but don’t wait; just return the change ID immediately.
- exec(command: List[str], *, service_context: str | None = None, environment: Dict[str, str] | None = None, working_dir: str | None = None, timeout: float | None = None, user_id: int | None = None, user: str | None = None, group_id: int | None = None, group: str | None = None, stdin: str | TextIO | None = None, stdout: TextIO | None = None, stderr: TextIO | None = None, encoding: str = 'utf-8', combine_stderr: bool = False) ExecProcess[str] [source]¶
- exec(command: List[str], *, service_context: str | None = None, environment: Dict[str, str] | None = None, working_dir: str | None = None, timeout: float | None = None, user_id: int | None = None, user: str | None = None, group_id: int | None = None, group: str | None = None, stdin: bytes | BinaryIO | None = None, stdout: BinaryIO | None = None, stderr: BinaryIO | None = None, encoding: None = None, combine_stderr: bool = False) ExecProcess[bytes]
Execute the given command on the remote system.
Two method signatures are shown because this method returns an
ExecProcess
that deals with strings ifencoding
is specified (the default ), or one that deals with bytes ifencoding
is set toNone
.Most of the parameters are explained in the “Parameters” section below, however, input/output handling is a bit more complex. Some examples are shown below:
# Simple command with no output; just check exit code >>> process = client.exec(['send-emails']) >>> process.wait() # Fetch output as string >>> process = client.exec(['python3', '--version']) >>> version, _ = process.wait_output() >>> print(version) Python 3.8.10 # Fetch both stdout and stderr as strings >>> process = client.exec(['pg_dump', '-s', ...]) >>> schema, logs = process.wait_output() # Stream input from a string and write output to files >>> stdin = 'foo\nbar\n' >>> with open('out.txt', 'w') as out, open('err.txt', 'w') as err: ... process = client.exec(['awk', '{ print toupper($0) }'], ... stdin=stdin, stdout=out, stderr=err) ... process.wait() >>> open('out.txt').read() 'FOO\nBAR\n' >>> open('err.txt').read() '' # Real-time streaming using ExecProcess.stdin and ExecProcess.stdout >>> process = client.exec(['cat']) >>> def stdin_thread(): ... for line in ['one\n', '2\n', 'THREE\n']: ... process.stdin.write(line) ... process.stdin.flush() ... time.sleep(1) ... process.stdin.close() ... >>> threading.Thread(target=stdin_thread).start() >>> for line in process.stdout: ... print(datetime.datetime.now().strftime('%H:%M:%S'), repr(line)) ... 16:20:26 'one\n' 16:20:27 '2\n' 16:20:28 'THREE\n' >>> process.wait() # will return immediately as stdin was closed # Show exception raised for non-zero return code >>> process = client.exec(['ls', 'notexist']) >>> out, err = process.wait_output() Traceback (most recent call last): ... ExecError: "ls" returned exit code 2 >>> exc = sys.last_value >>> exc.exit_code 2 >>> exc.stdout '' >>> exc.stderr "ls: cannot access 'notfound': No such file or directory\n"
- Parameters:
command – Command to execute: the first item is the name (or path) of the executable, the rest of the items are the arguments.
service_context – If specified, run the command in the context of this service. Specifically, inherit its environment variables, user/group settings, and working directory. The other exec options will override the service context;
environment
will be merged on top of the service’s.environment – Environment variables to pass to the process.
working_dir – Working directory to run the command in. If not set, Pebble uses the target user’s $HOME directory (and if the user argument is not set, $HOME of the user Pebble is running as).
timeout – Timeout in seconds for the command execution, after which the process will be terminated. If not specified, the execution never times out.
user_id – User ID (UID) to run the process as.
user – Username to run the process as. User’s UID must match user_id if both are specified.
group_id – Group ID (GID) to run the process as.
group – Group name to run the process as. Group’s GID must match group_id if both are specified.
stdin – A string or readable file-like object that is sent to the process’s standard input. If not set, the caller can write input to
ExecProcess.stdin
to stream input to the process.stdout – A writable file-like object that the process’s standard output is written to. If not set, the caller can use
ExecProcess.wait_output()
to capture output as a string, or read fromExecProcess.stdout()
to stream output from the process.stderr – A writable file-like object that the process’s standard error is written to. If not set, the caller can use
ExecProcess.wait_output()
to capture error output as a string, or read fromExecProcess.stderr()
to stream error output from the process. Must be None if combine_stderr is True.encoding – If encoding is set (the default is UTF-8), the types read or written to stdin/stdout/stderr are str, and encoding is used to encode them to bytes. If encoding is None, the types read or written are raw bytes.
combine_stderr – If True, process’s stderr output is combined into its stdout (the stderr argument must be None). If False, separate streams are used for stdout and stderr.
- Returns:
A Process object representing the state of the running process. To wait for the command to finish, the caller will typically call
ExecProcess.wait()
if stdout/stderr were provided as arguments toexec()
, orExecProcess.wait_output()
if not.
- get_changes(select: ChangeState = ChangeState.IN_PROGRESS, service: str | None = None) List[Change] [source]¶
Get list of changes in given state, filter by service name if given.
- get_checks(level: CheckLevel | None = None, names: Iterable[str] | None = None) List[CheckInfo] [source]¶
Get the check status for the configured checks.
- Parameters:
level – Optional check level to query for (default is to fetch checks with any level).
names – Optional list of check names to query for (default is to fetch all checks).
- Returns:
List of
CheckInfo
objects.
- get_services(names: Iterable[str] | None = None) List[ServiceInfo] [source]¶
Get the service status for the configured services.
If names is specified, only fetch the service status for the services named.
- get_system_info() SystemInfo [source]¶
Get system info.
- get_warnings(select: WarningState = WarningState.PENDING) List[Warning] [source]¶
Get list of warnings in given state (pending or all).
- list_files(path: str, *, pattern: str | None = None, itself: bool = False) List[FileInfo] [source]¶
Return list of directory entries from given path on remote system.
Despite the name, this method returns a list of files and directories, similar to
os.listdir()
oros.scandir()
.- Parameters:
path – Path of the directory to list, or path of the file to return information about.
pattern – If specified, filter the list to just the files that match, for example
*.txt
.itself – If path refers to a directory, return information about the directory itself, rather than its contents.
- make_dir(path: str, *, make_parents: bool = False, permissions: int | None = None, user_id: int | None = None, user: str | None = None, group_id: int | None = None, group: str | None = None)[source]¶
Create a directory on the remote system with the given attributes.
- Parameters:
path – Path of the directory to create on the remote system.
make_parents – If True, create parent directories if they don’t exist.
permissions – Permissions (mode) to create directory with (Pebble default is 0o755).
user_id – User ID (UID) for directory.
user – Username for directory. User’s UID must match user_id if both are specified.
group_id – Group ID (GID) for directory.
group – Group name for directory. Group’s GID must match group_id if both are specified.
- pull(path: str, *, encoding: str | None = 'utf-8') BinaryIO | TextIO [source]¶
Read a file’s content from the remote system.
- Parameters:
path – Path of the file to read from the remote system.
encoding – Encoding to use for decoding the file’s bytes to str, or None to specify no decoding.
- Returns:
A readable file-like object, whose read() method will return str objects decoded according to the specified encoding, or bytes if encoding is None.
- Raises:
PathError – If there was an error reading the file at path, for example, if the file doesn’t exist or is a directory.
- push(path: str, source: _IOSource, *, encoding: str = 'utf-8', make_dirs: bool = False, permissions: int | None = None, user_id: int | None = None, user: str | None = None, group_id: int | None = None, group: str | None = None)[source]¶
Write content to a given file path on the remote system.
- Parameters:
path – Path of the file to write to on the remote system.
source – Source of data to write. This is either a concrete str or bytes instance, or a readable file-like object.
encoding – Encoding to use for encoding source str to bytes, or strings read from source if it is a TextIO type. Ignored if source is bytes or BinaryIO.
make_dirs – If True, create parent directories if they don’t exist.
permissions – Permissions (mode) to create file with (Pebble default is 0o644).
user_id – User ID (UID) for file.
user – Username for file. User’s UID must match user_id if both are specified.
group_id – Group ID (GID) for file.
group – Group name for file. Group’s GID must match group_id if both are specified.
- remove_path(path: str, *, recursive: bool = False)[source]¶
Remove a file or directory on the remote system.
- Parameters:
path – Path of the file or directory to delete from the remote system.
recursive – If True, and path is a directory recursively deletes it and everything under it. If the path is a file, delete the file and do nothing if the file is non-existent. Behaviourally similar to
rm -rf <file|dir>
.
- replan_services(timeout: float = 30.0, delay: float = 0.1) ChangeID [source]¶
Replan by (re)starting changed and startup-enabled services and wait for them to start.
- Parameters:
timeout – Seconds before replan change is considered timed out (float).
delay – Seconds before executing the replan change (float).
- Returns:
ChangeID of the replan change.
- Raises:
ChangeError – if one or more of the services didn’t stop/start. If timeout is 0, submit the action but don’t wait; just return the change ID immediately.
- restart_services(services: Iterable[str], timeout: float = 30.0, delay: float = 0.1) ChangeID [source]¶
Restart services by name and wait (poll) for them to be started.
- Parameters:
services – Non-empty list of services to restart.
timeout – Seconds before restart change is considered timed out (float).
delay – Seconds before executing the restart change (float).
- Returns:
ChangeID of the restart change.
- Raises:
ChangeError – if one or more of the services didn’t stop/start. If timeout is 0, submit the action but don’t wait; just return the change ID immediately.
- send_signal(sig: int | str, services: Iterable[str])[source]¶
Send the given signal to the list of services named.
- Parameters:
sig – Name or number of signal to send, for example
"SIGHUP"
,1
, orsignal.SIGHUP
.services – Non-empty list of service names to send the signal to.
- Raises:
APIError – If any of the services are not in the plan or are not currently running.
- start_services(services: Iterable[str], timeout: float = 30.0, delay: float = 0.1) ChangeID [source]¶
Start services by name and wait (poll) for them to be started.
- Parameters:
services – Non-empty list of services to start.
timeout – Seconds before start change is considered timed out (float).
delay – Seconds before executing the start change (float).
- Returns:
ChangeID of the start change.
- Raises:
ChangeError – if one or more of the services didn’t stop/start. If timeout is 0, submit the action but don’t wait; just return the change ID immediately.
- stop_services(services: Iterable[str], timeout: float = 30.0, delay: float = 0.1) ChangeID [source]¶
Stop services by name and wait (poll) for them to be started.
- Parameters:
services – Non-empty list of services to stop.
timeout – Seconds before stop change is considered timed out (float).
delay – Seconds before executing the stop change (float).
- Returns:
ChangeID of the stop change.
- Raises:
ChangeError – if one or more of the services didn’t stop/start. If timeout is 0, submit the action but don’t wait; just return the change ID immediately.
- wait_change(change_id: ChangeID, timeout: float | None = 30.0, delay: float = 0.1) Change [source]¶
Wait for the given change to be ready.
If the Pebble server supports the /v1/changes/{id}/wait API endpoint, use that to avoid polling, otherwise poll /v1/changes/{id} every delay seconds.
- Parameters:
change_id – Change ID of change to wait for.
timeout – Maximum time in seconds to wait for the change to be ready. It may be None, in which case wait_change never times out.
delay – If polling, this is the delay in seconds between attempts.
- Returns:
The Change object being waited on.
- Raises:
TimeoutError – If the maximum timeout is reached.
- exception ops.pebble.ConnectionError[source]¶
Bases:
Error
Raised when the Pebble client can’t connect to the socket.
- exception ops.pebble.Error[source]¶
Bases:
Exception
Base class of most errors raised by the Pebble client.
- class ops.pebble.ExecDict¶
Bases:
dict
- ExecDict.group-id
- ExecDict.service-context
- ExecDict.user-id
- ExecDict.working-dir
- exception ops.pebble.ExecError(command: List[str], exit_code: int, stdout: AnyStr | None, stderr: AnyStr | None)[source]¶
-
Raised when a
Client.exec()
command returns a non-zero exit code.- STR_MAX_OUTPUT = 1024¶
Maximum number of characters that stdout/stderr are truncated to in
__str__
.
- stderr: AnyStr | None¶
Standard error from the process.
If
ExecProcess.wait_output()
was being called andcombine_stderr
was False, this is the captured stderr as a str (or bytes if encoding was None). IfExecProcess.wait()
was being called orcombine_stderr
was True, this is None.
- stdout: AnyStr | None¶
Standard output from the process.
If
ExecProcess.wait_output()
was being called, this is the captured stdout as a str (or bytes if encoding was None). IfExecProcess.wait()
was being called, this is None.
- class ops.pebble.ExecProcess(stdin: IO | None, stdout: IO | None, stderr: IO | None, client: Client, timeout: float | None, control_ws: _WebSocket, stdio_ws: _WebSocket, stderr_ws: _WebSocket | None, command: List[str], encoding: str | None, change_id: ChangeID, cancel_stdin: Callable[[], None] | None, cancel_reader: int | None, threads: List[Thread])[source]¶
Bases:
Generic
Represents a process started by
Client.exec()
.To avoid deadlocks, most users should use
wait_output()
instead of reading and writing thestdin
,stdout
, andstderr
attributes directly. Alternatively, users can pass stdin/stdout/stderr toClient.exec()
.This class should not be instantiated directly, only via
Client.exec()
.- send_signal(sig: int | str)[source]¶
Send the given signal to the running process.
- Parameters:
sig – Name or number of signal to send, e.g., “SIGHUP”, 1, or signal.SIGHUP.
- stderr: IO | None¶
Standard error from the process.
If the stderr argument was not passed to
Client.exec()
andcombine_stderr
was False, this is a readable file-like object the caller can use to stream error output from the process. It is None if stderr was passed toClient.exec()
orcombine_stderr
was True.
- stdin: IO | None¶
Standard input for the process.
If the stdin argument was not passed to
Client.exec()
, this is a writable file-like object the caller can use to stream input to the process. It is None if stdin was passed toClient.exec()
.
- stdout: IO | None¶
Standard output from the process.
If the stdout argument was not passed to
Client.exec()
, this is a readable file-like object the caller can use to stream output from the process. It is None if stdout was passed toClient.exec()
.
- wait()[source]¶
Wait for the process to finish.
If a timeout was specified to the
Client.exec()
call, this waits at most that duration.- Raises:
ChangeError – if there was an error starting or running the process.
ExecError – if the process exits with a non-zero exit code.
- wait_output() Tuple[AnyStr, AnyStr | None] [source]¶
Wait for the process to finish and return tuple of (stdout, stderr).
If a timeout was specified to the
Client.exec()
call, this waits at most that duration. If combine_stderr was True, stdout will include the process’s standard error, and stderr will be None.- Raises:
ChangeError – if there was an error starting or running the process.
ExecError – if the process exits with a non-zero exit code.
- class ops.pebble.FileInfo(path: str, name: str, type: FileType | str, size: int | None, permissions: int, last_modified: datetime, user_id: int | None, user: str | None, group_id: int | None, group: str | None)[source]¶
Bases:
object
Stat-like information about a single file or directory.
- class ops.pebble.FileType(value, names=None, *, module=None, qualname=None, type=None, start=1, boundary=None)[source]¶
Bases:
Enum
Enum of file types.
- DEVICE = 'device'¶
- DIRECTORY = 'directory'¶
- FILE = 'file'¶
- NAMED_PIPE = 'named-pipe'¶
- SOCKET = 'socket'¶
- SYMLINK = 'symlink'¶
- UNKNOWN = 'unknown'¶
- class ops.pebble.Layer(raw: str | LayerDict | None = None)[source]¶
Bases:
object
Represents a Pebble configuration layer.
The format of this is documented at https://github.com/canonical/pebble/#layer-specification.
- exception ops.pebble.PathError(kind: str, message: str)[source]¶
Bases:
Error
Raised when there’s an error with a specific path.
- class ops.pebble.Plan(raw: str)[source]¶
Bases:
object
Represents the effective Pebble configuration.
A plan is the combined layer configuration. The layer configuration is documented at https://github.com/canonical/pebble/#layer-specification.
- property checks: Dict[str, Check]¶
This plan’s checks mapping (maps check name to
Check
).This property is currently read-only.
- exception ops.pebble.ProtocolError[source]¶
Bases:
Error
Raised when there’s a higher-level protocol error talking to Pebble.
- class ops.pebble.Service(name: str, raw: ServiceDict | None = None)[source]¶
Bases:
object
Represents a service description in a Pebble configuration layer.
- to_dict() ServiceDict [source]¶
Convert this service object to its dict representation.
- class ops.pebble.ServiceDict¶
Bases:
dict
- ServiceDict.backoff-delay
- ServiceDict.backoff-factor
- ServiceDict.backoff-limit
- ServiceDict.group-id
- ServiceDict.kill-delay
- ServiceDict.on-check-failure
- ServiceDict.on-failure
- ServiceDict.on-success
- ServiceDict.user-id
- ServiceDict.working-dir
- class ops.pebble.ServiceInfo(name: str, startup: ServiceStartup | str, current: ServiceStatus | str)[source]¶
Bases:
object
Service status information.
- classmethod from_dict(d: _ServiceInfoDict) ServiceInfo [source]¶
Create new ServiceInfo object from dict parsed from JSON.
- class ops.pebble.ServiceStartup(value, names=None, *, module=None, qualname=None, type=None, start=1, boundary=None)[source]¶
Bases:
Enum
Enum of service startup options.
- DISABLED = 'disabled'¶
- ENABLED = 'enabled'¶
- class ops.pebble.ServiceStatus(value, names=None, *, module=None, qualname=None, type=None, start=1, boundary=None)[source]¶
Bases:
Enum
Enum of service statuses.
- ACTIVE = 'active'¶
- ERROR = 'error'¶
- INACTIVE = 'inactive'¶
- class ops.pebble.SystemInfo(version: str)[source]¶
Bases:
object
System information object.
- classmethod from_dict(d: _SystemInfoDict) SystemInfo [source]¶
Create new SystemInfo object from dict parsed from JSON.
- class ops.pebble.Task(id: TaskID, kind: str, summary: str, status: str, log: List[str], progress: TaskProgress, spawn_time: datetime, ready_time: datetime | None, data: Dict[str, Any] | None = None)[source]¶
Bases:
object
Task object.
- class ops.pebble.TaskProgress(label: str, done: int, total: int)[source]¶
Bases:
object
Task progress object.
- classmethod from_dict(d: _ProgressDict) TaskProgress [source]¶
Create new TaskProgress object from dict parsed from JSON.
- exception ops.pebble.TimeoutError[source]¶
Bases:
TimeoutError
,Error
Raised when a polling timeout occurs.
ops.testing module¶
Infrastructure to build unit tests for charms using the ops library.
- class ops.testing.ExecArgs(command: List[str], environment: Dict[str, str], working_dir: str | None, timeout: float | None, user_id: int | None, user: str | None, group_id: int | None, group: str | None, stdin: str | bytes | None, encoding: str | None, combine_stderr: bool)[source]¶
Bases:
object
Represent arguments captured from the
ops.Container.exec()
method call.These arguments will be passed to the
Harness.handle_exec()
handler function. Seeops.pebble.Client.exec()
for documentation of properties.