From 09942e57a97fb943e5ff740749ce149f018d6da6 Mon Sep 17 00:00:00 2001
From: Nicolas Ledez <github.public@ledez.net>
Date: Mon, 2 Oct 2023 16:48:57 +0200
Subject: [PATCH] Add prometheus /metrics

---
 setup.cfg           |  1 +
 zou/app/__init__.py | 23 +++++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/setup.cfg b/setup.cfg
index 2e31c788d2..437b579040 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -58,6 +58,7 @@ install_requires =
     OpenTimelineIO==0.15.0
     orjson==3.9.7
     pillow==10.0.1
+    prometheus-client==0.17.1
     psutil==5.9.5
     psycopg[binary]==3.1.12
     pygelf==0.4.2
diff --git a/zou/app/__init__.py b/zou/app/__init__.py
index 2dd2852471..73555085e1 100644
--- a/zou/app/__init__.py
+++ b/zou/app/__init__.py
@@ -1,6 +1,8 @@
 import os
 import flask_fs
 import traceback
+import time
+import threading
 
 from flask import Flask, jsonify, current_app
 from flasgger import Swagger
@@ -10,6 +12,9 @@
 from flask_migrate import Migrate
 from flask_mail import Mail
 
+from werkzeug.middleware.dispatcher import DispatcherMiddleware
+import prometheus_client
+
 from jwt import ExpiredSignatureError
 from babel.core import UnknownLocaleError
 from meilisearch.errors import (
@@ -58,6 +63,21 @@
     app, template=swagger.swagger_template, config=swagger.swagger_config
 )
 
+BACKGROUND_TASKS = prometheus_client.Counter(
+    "background_tasks_total", "Background tasks executed."
+)
+
+
+def background_task():
+    """Background task to simulate and update metrics"""
+    while True:
+        time.sleep(5)  # Run every 5 seconds
+        BACKGROUND_TASKS.inc()  # Increment our counter
+
+
+app.wsgi_app = DispatcherMiddleware(
+    app.wsgi_app, {"/metrics": prometheus_client.make_wsgi_app()}
+)
 
 if config.SENTRY_DEBUG_URL:
 
@@ -168,5 +188,8 @@ def load_api():
     fs.mkdir_p(app.config["TMP_DIR"])
     configure_auth()
 
+    t = threading.Thread(target=background_task)
+    t.start()
+
 
 load_api()