Versioned notifications for actions

https://blueprints.launchpad.net/watcher/+spec/action-versioned-notifications-api

Following the implementation of the watcher-notifications-ovo blueprint, Watcher now has all the necessary prerequisites in order to provide versioned notifications throughout its codebase. This blueprint will focus on describing the notifications to implement in Watcher concerning the Action object.

Problem description

As of now, there is no way for any service (Watcher included) to know when an action has been created, modified or deleted. This prevents any form of event-based reaction which may be useful for 3rd party services or plugins.

Use Cases

As an OpenStack developer, I want to be able to listen to notifications coming from Watcher about actions.

As an OpenStack developer, I want to know what the format of the action notifications are.

As an OpenStack developer, I want to be notified whenever:

  • an action has been created
  • an action is updated
  • an action has been deleted

As an OpenStack developer, I would also want to be notified whenever:

  • an action starts its execution
  • an action finishes its execution
  • the execution of an action failed

Proposed change

In order to implement the above use cases, many different notifications will be needed:

  • action.create whenever an action has been created.
  • action.update whenever an action has been updated. This includes all state updates including the deletion of the action.
  • action.delete whenever an action has been deleted (soft).
  • action.execution.start whenever an action starts.
  • action.execution.end whenever an action ends.
  • action.execution.error whenever an action fails.

Moreover, we will rely on oslo.versionedobjects to version the payloads of action-related notifications.

Here below is suggestion of notification structure for each one of the aforementioned events:

action.create

{
  "priority": "INFO",
  "payload": {
    "watcher_object.data": {
      "state": "PENDING",
      "updated_at": null,
      "deleted_at": null,
      "action_plan": {
        "watcher_object.data": {
          "uuid": "bc830f84-8ae3-4fc6-8bc6-e3dd15e8b49a",
          "updated_at": null,
          "deleted_at": null,
          "created_at": "2016-11-04T16:25:35Z",
        },
        "watcher_object.name": "ActionPlanPayload",
        "watcher_object.version": "1.0",
        "watcher_object.namespace": "watcher"
      },
      "interval": null,
      "scope": [],
      "strategy": {
        "watcher_object.data": {
          "parameters_spec": {
            "properties": {
              "para2": {
                "type": "string",
                "default": "hello",
                "description": "string parameter example"
              },
              "para1": {
                "description": "number parameter example",
                "maximum": 10.2,
                "type": "number",
                "default": 3.2,
                "minimum": 1.0
              }
            }
          },
          "name": "dummy",
          "uuid": "75234dfe-87e3-4f11-a0e0-3c3305d86a39",
          "updated_at": null,
          "deleted_at": null,
          "created_at": "2016-11-04T16:25:35Z",
          "display_name": "Dummy strategy"
        },
        "watcher_object.name": "StrategyPayload",
        "watcher_object.version": "1.0",
        "watcher_object.namespace": "watcher"
      },
      "created_at": "2016-11-04T16:29:20Z",
      "uuid": "4a97b9dd-2023-43dc-b713-815bdd94d4d6"
    },
    "watcher_object.name": "ActionCreatePayload",
    "watcher_object.version": "1.0",
    "watcher_object.namespace": "watcher"
  },
  "publisher_id": "infra-optim:localhost",
  "timestamp": "2016-11-04 16:31:36.264673   ",
  "event_type": "action.create",
  "message_id": "cbcf9f2c-7c53-4b4d-91ec-db49cca024b6"
}

action.update

{
  "publisher_id": "infra-optim:localhost",
  "timestamp": "2016-11-04 16:51:38.722986   ",
  "payload": {
    "watcher_object.name": "ActionUpdatePayload",
    "watcher_object.data": {
      "strategy": {
        "watcher_object.name": "StrategyPayload",
        "watcher_object.data": {
          "name": "dummy",
          "parameters_spec": {
            "properties": {
              "para2": {
                "default": "hello",
                "type": "string",
                "description": "string parameter example"
              },
              "para1": {
                "maximum": 10.2,
                "default": 3.2,
                "minimum": 1.0,
                "description": "number parameter example",
                "type": "number"
              }
            }
          },
          "updated_at": null,
          "display_name": "Dummy strategy",
          "deleted_at": null,
          "uuid": "75234dfe-87e3-4f11-a0e0-3c3305d86a39",
          "created_at": "2016-11-04T16:25:35Z"
        },
        "watcher_object.namespace": "watcher",
        "watcher_object.version": "1.0"
      },
      "scope": [],
      "created_at": "2016-11-04T16:51:21Z",
      "uuid": "f1e0d912-afd9-4bf2-91ef-c99cd08cc1ef",
      "goal": {
        "watcher_object.name": "GoalPayload",
        "watcher_object.data": {
          "efficacy_specification": [],
          "updated_at": null,
          "name": "dummy",
          "display_name": "Dummy goal",
          "deleted_at": null,
          "uuid": "bc830f84-8ae3-4fc6-8bc6-e3dd15e8b49a",
          "created_at": "2016-11-04T16:25:35Z"
        },
        "watcher_object.namespace": "watcher",
        "watcher_object.version": "1.0"
      },
      "parameters": {
        "para2": "hello",
        "para1": 3.2
      },
      "deleted_at": null,
      "state_update": {
        "watcher_object.name": "ActionStateUpdatePayload",
        "watcher_object.data": {
          "state": "ONGOING",
          "old_state": "PENDING"
        },
        "watcher_object.namespace": "watcher",
        "watcher_object.version": "1.0"
      },
      "interval": null,
      "updated_at": null,
      "state": "ONGOING",
      "action_type": "NOP"
    },
    "watcher_object.namespace": "watcher",
    "watcher_object.version": "1.0"
  },
  "priority": "INFO",
  "event_type": "action.update",
  "message_id": "697fdf55-7252-4b6c-a2c2-5b9e85f6342c"
}

action.delete

{
  "priority": "INFO",
  "payload": {
    "watcher_object.data": {
      "action_type": "NOP",
      "parameters": {
        "para2": "hello",
        "para1": 3.2
      },
      "state": "DELETED",
      "updated_at": null,
      "deleted_at": null,
      "goal": {
        "watcher_object.data": {
          "uuid": "bc830f84-8ae3-4fc6-8bc6-e3dd15e8b49a",
          "name": "dummy",
          "updated_at": null,
          "deleted_at": null,
          "efficacy_specification": [],
          "created_at": "2016-11-04T16:25:35Z",
          "display_name": "Dummy goal"
        },
        "watcher_object.name": "GoalPayload",
        "watcher_object.version": "1.0",
        "watcher_object.namespace": "watcher"
      },
      "interval": null,
      "scope": [],
      "strategy": {
        "watcher_object.data": {
          "parameters_spec": {
            "properties": {
              "para2": {
                "type": "string",
                "default": "hello",
                "description": "string parameter example"
              },
              "para1": {
                "description": "number parameter example",
                "maximum": 10.2,
                "type": "number",
                "default": 3.2,
                "minimum": 1.0
              }
            }
          },
          "name": "dummy",
          "uuid": "75234dfe-87e3-4f11-a0e0-3c3305d86a39",
          "updated_at": null,
          "deleted_at": null,
          "created_at": "2016-11-04T16:25:35Z",
          "display_name": "Dummy strategy"
        },
        "watcher_object.name": "StrategyPayload",
        "watcher_object.version": "1.0",
        "watcher_object.namespace": "watcher"
      },
      "created_at": "2016-11-04T16:29:20Z",
      "uuid": "4a97b9dd-2023-43dc-b713-815bdd94d4d6"
    },
    "watcher_object.name": "ActionDeletePayload",
    "watcher_object.version": "1.0",
    "watcher_object.namespace": "watcher"
  },
  "publisher_id": "infra-optim:localhost",
  "timestamp": "2016-11-04 16:31:36.264673   ",
  "event_type": "action.delete",
  "message_id": "cbcf9f2c-7c53-4b4d-91ec-db49cca024b6"
}

action.execution.start

{
  "priority": "INFO",
  "payload": {
    "watcher_object.data": {
      "action_type": "NOP",
      "parameters": {
        "para2": "hello",
        "para1": 3.2
      },
      "state": "ONGOING",
      "updated_at": null,
      "deleted_at": null,
      "fault": null,
      "goal": {
        "watcher_object.data": {
          "uuid": "bc830f84-8ae3-4fc6-8bc6-e3dd15e8b49a",
          "name": "dummy",
          "updated_at": null,
          "deleted_at": null,
          "efficacy_specification": [],
          "created_at": "2016-11-04T16:25:35Z",
          "display_name": "Dummy goal"
        },
        "watcher_object.name": "GoalPayload",
        "watcher_object.version": "1.0",
        "watcher_object.namespace": "watcher"
      },
      "interval": null,
      "scope": [],
      "strategy": {
        "watcher_object.data": {
          "parameters_spec": {
            "properties": {
              "para2": {
                "type": "string",
                "default": "hello",
                "description": "string parameter example"
              },
              "para1": {
                "description": "number parameter example",
                "maximum": 10.2,
                "type": "number",
                "default": 3.2,
                "minimum": 1.0
              }
            }
          },
          "name": "dummy",
          "uuid": "75234dfe-87e3-4f11-a0e0-3c3305d86a39",
          "updated_at": null,
          "deleted_at": null,
          "created_at": "2016-11-04T16:25:35Z",
          "display_name": "Dummy strategy"
        },
        "watcher_object.name": "StrategyPayload",
        "watcher_object.version": "1.0",
        "watcher_object.namespace": "watcher"
      },
      "created_at": "2016-11-04T16:29:20Z",
      "uuid": "4a97b9dd-2023-43dc-b713-815bdd94d4d6"
    },
    "watcher_object.name": "ActionActionPayload",
    "watcher_object.version": "1.0",
    "watcher_object.namespace": "watcher"
  },
  "publisher_id": "infra-optim:localhost",
  "timestamp": "2016-11-04 16:31:36.264673   ",
  "event_type": "action.execution.start",
  "message_id": "cbcf9f2c-7c53-4b4d-91ec-db49cca024b6"
}

action.execution.end

{
  "priority": "INFO",
  "payload": {
    "watcher_object.data": {
      "action_type": "NOP",
      "parameters": {
        "para2": "hello",
        "para1": 3.2
      },
      "state": "ONGOING",
      "updated_at": null,
      "deleted_at": null,
      "fault": null,
      "goal": {
        "watcher_object.data": {
          "uuid": "bc830f84-8ae3-4fc6-8bc6-e3dd15e8b49a",
          "name": "dummy",
          "updated_at": null,
          "deleted_at": null,
          "efficacy_specification": [],
          "created_at": "2016-11-04T16:25:35Z",
          "display_name": "Dummy goal"
        },
        "watcher_object.name": "GoalPayload",
        "watcher_object.version": "1.0",
        "watcher_object.namespace": "watcher"
      },
      "interval": null,
      "scope": [],
      "strategy": {
        "watcher_object.data": {
          "parameters_spec": {
            "properties": {
              "para2": {
                "type": "string",
                "default": "hello",
                "description": "string parameter example"
              },
              "para1": {
                "description": "number parameter example",
                "maximum": 10.2,
                "type": "number",
                "default": 3.2,
                "minimum": 1.0
              }
            }
          },
          "name": "dummy",
          "uuid": "75234dfe-87e3-4f11-a0e0-3c3305d86a39",
          "updated_at": null,
          "deleted_at": null,
          "created_at": "2016-11-04T16:25:35Z",
          "display_name": "Dummy strategy"
        },
        "watcher_object.name": "StrategyPayload",
        "watcher_object.version": "1.0",
        "watcher_object.namespace": "watcher"
      },
      "created_at": "2016-11-04T16:29:20Z",
      "uuid": "4a97b9dd-2023-43dc-b713-815bdd94d4d6"
    },
    "watcher_object.name": "ActionActionPayload",
    "watcher_object.version": "1.0",
    "watcher_object.namespace": "watcher"
  },
  "publisher_id": "infra-optim:localhost",
  "timestamp": "2016-11-04 16:31:36.264673   ",
  "event_type": "action.execution.end",
  "message_id": "cbcf9f2c-7c53-4b4d-91ec-db49cca024b6"
}

action.execution.error

{
  "priority": "ERROR",
  "payload": {
    "watcher_object.data": {
      "action_type": "NOP",
      "parameters": {
        "para2": "hello",
        "para1": 3.2
      },
      "state": "ONGOING",
      "updated_at": null,
      "deleted_at": null,
      "fault": {
        "watcher_object.data": {
          "exception": "WatcherException",
          "exception_message": "TEST",
          "function_name": "test_send_action_action_with_error",
          "module_name": "watcher.tests.notifications.test_action_notification"
        },
        "watcher_object.name": "ExceptionPayload",
        "watcher_object.namespace": "watcher",
        "watcher_object.version": "1.0"
      },
      "goal": {
        "watcher_object.data": {
          "uuid": "bc830f84-8ae3-4fc6-8bc6-e3dd15e8b49a",
          "name": "dummy",
          "updated_at": null,
          "deleted_at": null,
          "efficacy_specification": [],
          "created_at": "2016-11-04T16:25:35Z",
          "display_name": "Dummy goal"
        },
        "watcher_object.name": "GoalPayload",
        "watcher_object.version": "1.0",
        "watcher_object.namespace": "watcher"
      },
      "interval": null,
      "scope": [],
      "strategy": {
        "watcher_object.data": {
          "parameters_spec": {
            "properties": {
              "para2": {
                "type": "string",
                "default": "hello",
                "description": "string parameter example"
              },
              "para1": {
                "description": "number parameter example",
                "maximum": 10.2,
                "type": "number",
                "default": 3.2,
                "minimum": 1.0
              }
            }
          },
          "name": "dummy",
          "uuid": "75234dfe-87e3-4f11-a0e0-3c3305d86a39",
          "updated_at": null,
          "deleted_at": null,
          "created_at": "2016-11-04T16:25:35Z",
          "display_name": "Dummy strategy"
        },
        "watcher_object.name": "StrategyPayload",
        "watcher_object.version": "1.0",
        "watcher_object.namespace": "watcher"
      },
      "created_at": "2016-11-04T16:29:20Z",
      "uuid": "4a97b9dd-2023-43dc-b713-815bdd94d4d6"
    },
    "watcher_object.name": "ActionActionPayload",
    "watcher_object.version": "1.0",
    "watcher_object.namespace": "watcher"
  },
  "publisher_id": "infra-optim:localhost",
  "timestamp": "2016-11-04 16:31:36.264673   ",
  "event_type": "action.execution.error",
  "message_id": "cbcf9f2c-7c53-4b4d-91ec-db49cca024b6"
}

Alternatives

Instead of using versioned objects, we can define the payload of our action notifications without any support for versioning.

Data model impact

New versioned objects will be created although none of them are to be persisted as they will be used to structure the content of the notifications.

Here are some of the payloads to be declared:

@base.WatcherObjectRegistry.register_notification
class ActionPayload(notificationbase.NotificationPayloadBase):

    VERSION = '1.0'

    fields = {
        'uuid': fields.UUIDField(),
        'action_type': fields.StringField(),
        'state': fields.StringField(),
        'parameters': fields.FlexibleDictField(nullable=True),
        'interval': fields.IntegerField(nullable=True),
        'goal_uuid': fields.UUIDField(),
        'strategy_uuid': fields.UUIDField(nullable=True),
        'goal': fields.ObjectField('Goal'),
        'strategy': fields.ObjectField('Strategy', nullable=True),
        'created_at': fields.DateTimeField(nullable=True),
        'updated_at': fields.DateTimeField(nullable=True),
        'deleted_at': fields.DateTimeField(nullable=True),
    }


@base.WatcherObjectRegistry.register_notification
class ActionStateUpdatePayload(notificationbase.NotificationPayloadBase):

    VERSION = '1.0'

    fields = {
        'old_state': fields.StringField(nullable=True),
        'state': fields.StringField(nullable=True),
    }


@base.WatcherObjectRegistry.register_notification
class ActionUpdatePayload(ActionPayload):

    VERSION = '1.0'

    fields = {
        'state_update': fields.ObjectField('ActionStateUpdatePayload'),
    }

REST API impact

None.

Security impact

None.

Notifications impact

This blueprint will implement the following notifications:

  • action.create
  • action.update
  • action.delete
  • action.execution.start
  • action.execution.end
  • action.execution.error

Other end user impact

None.

Performance Impact

When enabled, code to send the notification will be called each time an event occurs that triggers a notification. This shouldn’t be much of a problem for Watcher itself, but the load on whatever message bus is used should be considered.

Other deployer impact

In order for the notifications to be emitted, the deployer will have to configure the notification topics using oslo.messaging. Other configuration options exposed via oslo.messaging may also be tuned.

Developer impact

Developers should adhere to proper versioning guidelines and use the notification base classes when creating/updating notifications.

Implementation

Assignee(s)

Primary assignee:
joker946 <a.chadin@servionica.ru>

Work Items

  • Implement action.create
  • Implement action.update
  • Implement action.delete
  • Implement action.execution.start
  • Implement action.execution.end
  • Implement action.execution.error

Testing

These notifications will have to be tested mainly via unit testing.

Documentation Impact

A notification sample should be provided and made dynamically available in the online documentation.

The sequence diagrams in the Watcher architecture.

References

None.