add prometheus exporter

matrix_alertbot/webhook.py

@@ -4,6 +4,8 @@ import logging
 from typing import Any
 
 from aiohttp import web, web_request
+from aiohttp_prometheus_exporter.handler import metrics
+from aiohttp_prometheus_exporter.middleware import prometheus_middleware_factory
 from diskcache import Cache
 from nio import AsyncClient, SendRetryError
 
@@ -57,6 +59,10 @@ class Webhook:
         self.app["config"] = config
         self.app["cache"] = cache
         self.app.add_routes(routes)
+
+        self.app.middlewares.append(prometheus_middleware_factory())
+        self.app.router.add_get("/metrics", metrics())
+
         self.runner = web.AppRunner(self.app)
 
         self.config = config