From 9c8e73b04f5285a27cc1141bbb2c28bccdd1fc8d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lauri=20V=C3=B5sandi?= <lauri@k-space.ee>
Date: Fri, 21 Oct 2022 12:06:51 +0300
Subject: [PATCH] Add Prometheus metrics

---
 meta-operator.py | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/meta-operator.py b/meta-operator.py
index 6372390..2ca8886 100755
--- a/meta-operator.py
+++ b/meta-operator.py
@@ -3,9 +3,11 @@ import asyncio
 import ecs_logging
 import logging
 import os
+import prometheus_async
 import random
 import string
 import yaml
+from prometheus_client import Counter, Gauge
 from kubernetes_asyncio.client.api_client import ApiClient
 from kubernetes_asyncio import client, config, watch
 from time import time
@@ -27,11 +29,27 @@ args = parser.parse_args()
 MY_POD_NAMESPACE = os.environ["MY_POD_NAMESPACE"]
 LABEL_MANAGED_BY = "meta-operator"
 
+counter_cleanups = Counter(
+    "meta_operator_cleanups",
+    "Count of executed cleanups",
+    ["stage"])
+counter_opened_watch_streams = Counter(
+    "meta_operator_opened_watch_streams",
+    "Count of watch streams opened")
+gauge_watch_stream_begin_timestamp = Gauge(
+    "meta_operator_watch_stream_begin_timestamp",
+    "Timestamp of last watch stream open")
+gauge_resource_version = Gauge(
+    "meta_operator_resource_version",
+    "Last observed resource version",
+    ["group", "version", "plural"])
+
 
 async def cleanup(v1, apps_api, label_selector, delay=0):
     ls = ",".join(label_selector)
     if delay:
         await asyncio.sleep(delay)
+
     logger.info("Cleaning up %s" % ls)
 
     # Clean up services
@@ -63,6 +81,7 @@ async def cleanup(v1, apps_api, label_selector, delay=0):
     for i in resp.items:
         logger.info("Removing secret: %s/%s", i.metadata.namespace, i.metadata.name)
         await v1.delete_namespaced_secret(i.metadata.name, i.metadata.namespace)
+    counter_cleanups.labels("executed").inc()
 
 
 async def apply_changes(operator, item, v1, revision, apps_api, api_instance):
@@ -130,6 +149,7 @@ async def apply_changes(operator, item, v1, revision, apps_api, api_instance):
     for name, body in transform_template(operator["spec"].get("deployments", [])):
         if replicas:
             body["spec"]["replicas"] = replicas
+
         try:
             await apps_api.replace_namespaced_deployment(name, namespace, body)
             logger.info("Updated deployment %s/%s", namespace, name)
@@ -165,15 +185,20 @@ async def update_loop(v1, apps_api, api_instance, revision):
     logger.info("Subscribing to %(plural)s.%(group)s/%(version)s updates", operator["spec"]["resource"])
     w = watch.Watch()
     latest_version = None
-
     task = None
+    counter_opened_watch_streams.inc()
 
     async for event in w.stream(method, *flt, resource_version=latest_version):
         latest_version = event["object"]["metadata"]["resourceVersion"]
+        gauge_resource_version.labels(
+            operator["spec"]["resource"]["group"],
+            operator["spec"]["resource"]["version"],
+            operator["spec"]["resource"]["plural"]).set(latest_version)
         if event["type"] == "ADDED":
             await apply_changes(operator, event["object"], v1, revision, apps_api, api_instance)
             if task:
                 task.cancel()
+                counter_cleanups.labels("postponed").inc()
             task = asyncio.create_task(cleanup(v1, apps_api,
                 label_selector + ("codemowers.io/revision!=%s" % revision,),
                 delay=2))
@@ -194,6 +219,7 @@ async def main():
         revision = str(time())
         while True:
             try:
+                gauge_watch_stream_begin_timestamp.set(time())
                 await update_loop(v1, apps_api, api_instance, revision)
             except asyncio.exceptions.TimeoutError:
                 pass
@@ -201,5 +227,6 @@ async def main():
 
 if __name__ == "__main__":
     loop = asyncio.new_event_loop()
+    loop.create_task(prometheus_async.aio.web.start_http_server(port=5000))
     loop.run_until_complete(main())
     loop.close()