Plugins¶
The service supports the system of plugins. Plugins must be written in the Python programming language.
Plugin types¶
There are three 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.
Supported event types:
event type
description
monitoring_event
Event contains monitoring points for sending to a custom monitoring system
Plugin example:
""" Module request monitoring plugin example """ import asyncio from abc import abstractmethod from typing import TypeVar from aiohttp import ClientSession from luna_plugins.base.plugins_meta.base_plugins import BaseEventPlugin MonitoringPoint = TypeVar("MonitoringPoint") LunaApplication = TypeVar("LunaApplication") class BaseRequestMonitoringPlugin(BaseEventPlugin): """ Base class for requests monitoring. """ # event name for triggering callback eventName = "monitoring_event" @abstractmethod async def flushPointToMonitoring(self, point: "MonitoringPoint", logger) -> None: """ All plugins must realize this method. This function call after end of request Args: point: point for monitoring logger: logger """ async def handleEvent(self, points: list["MonitoringPoint"], logger): await asyncio.gather(*[self.flushPointToMonitoring(point, logger) for point in points]) class RequestMonitoringPlugin(BaseRequestMonitoringPlugin): """ Example plugin sends a request data for monitoring to third-party source. Only one instance of this class exist during the program execution. """ def __init__(self, app: "LunaApplication"): super().__init__(app) self.url = "http://127.0.0.1:5020/1/buckets" self.session: ClientSession | None = None self.bucket = "plugin_test_bucket" async def close(self): """ Stop plugin. Close all open connections and ect """ if self.session: await self.session.close() async def initialize(self): """ Initialize plugin. Close all open connections and ect """ self.session = ClientSession() async with self.session.post(f"{self.url}?bucket={self.bucket}") as resp: if resp.status not in (201, 409): response = await resp.json() raise RuntimeError(f"failed create bucket, {self.bucket}, response: {response}") async def flushPointToMonitoring(self, point: "MonitoringPoint", logger) -> None: """ Callback for sending a request monitoring data. Args: point: point for monitoring logger: logger """ logger.debug(f"Plugin 'flushPointToMonitoring' get point, series: {point.series}, time: {point.eventTime}") msg = {"tags": point.tags, "fields": point.fields} async with self.session.post(f"{self.url}/{self.bucket}/objects", json=msg) as resp: logger.info(resp.status) logger.info(await resp.text())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
Plugin example:
""" Module realizes background plugin example """ import asyncio from asyncio import Task from luna_plugins.base.plugins_meta.base_plugins import BaseBackgroundHandler, BaseBackgroundPlugin, pluginHTTPResponse class HandlerExample(BaseBackgroundHandler): """ Handler example """ async def get(self, request): # pylint: disable=unused-argument """ Method get example. Returns: response """ return self.response(body="I am teapot", headers={"Content-Type": "text/plain"}, statusCode=418) def anotherHandlerExample(request): # pylint: disable=unused-argument """Standalone handler example""" return pluginHTTPResponse(statusCode=200, body="T800", headers={"Content-Type": "text/plain"}) class BackgroundPluginExample(BaseBackgroundPlugin): """ Background plugin example. Create background task and add a route. """ def __init__(self, app: "LunaApplication"): super().__init__(app) self.task: Task | None = None self.temperature = 0 async def initialize(self): """ Initialize plugin """ self.addRoute("/teapot", HandlerExample) self.addRoute("/teapot/version", anotherHandlerExample, methods={"get"}) async def close(self): """ Stop background process Returns: """ if self.task: self.task.cancel() async def usefulJob(self): """ Some useful async work """ while True: await asyncio.sleep(1) self.temperature = min(100, self.temperature + 1) if self.temperature < 100: self.app.ctx.logger.info(f"I boil water, temperature: {self.temperature}") else: self.app.ctx.logger.info("boiling water is ready, would you care for a cup of tea?") async def start(self): """ 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 """ self.task = asyncio.create_task(self.usefulJob())This plugin demonstrates background work and implements a route. All background plugins must implement the BaseRequestMonitoringPlugin abstract class.
Builtin plugin. This sort of plugin is provided only by VL and allow to get access to external VL services which not included to luna-platform. Each plugin provides access to part or whole resources of external service.
- At this moment available plugins are:
luna-streams
The plugin also check authorization parameters for access to several resources. It is possible to use Luna-Account-Id/Basic/Bearer authorization to make requests just like for all other endpoint of luna-api.
It is also possible to delimit access permissions using token permission. To make it possible, it needs to create new or update existing token passing custom token permission keys, for example {“permissions”: {“streams”: [“creation”, “view”, “modification”, “deletion”], “groups”: [“create”, “view”]}}
These parameters will works the same way as for all other luna-api resources.
Luna-Streams builtin plugin
- Requirements:
properly executed Luna-Streams service
properly specified plugin settings. For example:
"LUNA_API_PLUGINS_SETTINGS": { "luna-streams": { "luna-streams-address": {"origin": "http://127.0.0.1:5160", "api_version": 1}, "luna-streams-timeouts": {"request": 42, "connect": 42} } } }* prefix is /6/plugins/luna-streams
luna-api route
luna-streams route
description
permission key
prefix/version
/version
get luna-streams api version
prefix/docs/spec
/{api_version}/docs/spec
get luna-streams spec documentation
prefix/streams
/{api_version}/streams
create new/get/delete existing streams
streams
prefix/streams/count
/{api_version}/streams/count
get streams count
streams
prefix/streams/<stream-id>
/{api_version}/streams/<stream-id>
replace/get/delete stream
streams
prefix/plugins
/{api_version}/plugins
get list of active plugins
prefix/streams/logs
/{api_version}/streams/logs
get/delete streams logs
streams
prefix/streams/<stream-id> /preview/handler/live
/{api_version}/streams/<stream-id> /preview/handler/live
get stream live preview
streams streams
prefix/streams/<stream-id> /preview/handler/frame
/{api_version}/streams/logs /preview/handler/frame
get stream frame preview
streams streams
prefix/groups
/{api_version}/groups
create new/get existing groups
groups
prefix/groups/count
/{api_version}/groups/count
get groups count
groups
prefix/groups/<group-id>
/{api_version}/groups/<group-id>
update/get/delete group
groups
prefix/linker
/{api_version}/linker
link/unlink stream(s) to/from group(s)
groups
Note
It is allowed to make requests to Luna-Streams v1 or v2 api version using LUNA-STREAMS-API-VERSION header:
LUNA-STREAMS-API-VERSION header is not specified, the 1 luna-streams api_version will be selected
LUNA-STREAMS-API-VERSION header value is 1, the 1 luna-streams api_version will be selected
LUNA-STREAMS-API-VERSION header value is 2, the 2 luna-streams api_version will be selected
otherwise, an error will be received as respone
Enable plugin¶
If the user implements a plugin, the file with the plugin should be added to the luna_api/plugins directory of the service. The plugin filename should be added to the LUNA_API_ACTIVE_PLUGINS configuration setting.