Plugins

The service supports the system of plugins. Plugins must be written in the Python programming language.

Plugin types

There are two sorts of plugins:

• On event plugin. The plugin is triggered when an event occurs. The plugin should implement a callback function. This function is called on each event of the corresponding type. The set of event types is defined by the service developers.

  event type	description
  monitoring_event	Event contains monitoring points for sending to a custom monitoring system

  Monitoring plugin example:

  Module request monitoring plugin example

  class cow.plugins.plugin_examples.request_monitoring_plugin_example.BaseRequestMonitoringPlugin(app)

  Base class for requests monitoring.

  abstractmethod async flushPointToMonitoring(point, logger)

  All plugins must realize this method.

  This function call after end of request

  Parameters:

  • point (TypeVar(MonitoringPoint)) – point for monitoring

  • logger – logger

  Return type:

  None

  async handleEvent(points, logger)

  Handle event

  Parameters:

  • *args – positional arg for event handler function

  • **kwargs – named arg for event handler function

  class cow.plugins.plugin_examples.request_monitoring_plugin_example.RequestMonitoringPlugin(app)

  Example plugin sends a request data for monitoring to third-party source. Only one instance of this class exist during the program execution.

  async close()

  Stop plugin.

  Close all open connections and ect

  async flushPointToMonitoring(point, logger)

  Callback for sending a request monitoring data.

  Parameters:

  • point (TypeVar(MonitoringPoint)) – point for monitoring

  • logger – logger

  Return type:

  None

  async initialize()

  Initialize plugin.

  Close all open connections and ect

  This plugin demonstrates the sending of a request monitoring data to another service. All monitoring plugins must implement the BaseRequestMonitoringPlugin abstract class.

• Background plugin. This sort of plugin is intended for background work.

  The background plugin can implement:

  • custom route

  • background monitoring of service resources

  • collaboration of an event plugin and a background plugin (batching monitoring points)

  • connection to other data sources (Redis, RabbitMQ) and their data processing

    Module realizes background plugin example

    class cow.plugins.plugin_examples.background_plugin_example.BackgroundPluginExample(app)

    Background plugin example.

    Create background task and add a route.

    async close()

    Stop background process Returns:

    async initialize()

    Initialize plugin

    async start()

    Run background process

    Warning

    The function suppose that the process is handle in this coroutine. The coroutine must start the process only without awaiting a end of the process

    async usefulJob()

    Some useful async work

    class cow.plugins.plugin_examples.background_plugin_example.HandlerExample

    Handler example

    async get(request)

    Method get example.

    Returns:

    response

    cow.plugins.plugin_examples.background_plugin_example.anotherHandlerExample(request)

    Standalone handler example

  This plugin demonstrates background work and implements a route. All background plugins must implement the BaseRequestMonitoringPlugin abstract class.

Enable plugin

If the user implements a plugin, the file with the plugin should be added to the luna_video_agent/plugins directory of the service. The plugin filename should be added to the LUNA_VIDEO_AGENT_ACTIVE_PLUGINS configuration setting.