Add support for mounting the prometheus metrics directly on the Flask app

README.md

@@ -55,3 +55,20 @@ flask_request_latency_seconds_sum{endpoint="/",method="GET"} 0.00100278854370117
 ```
 
 Beware, this seems to not work when the app is run in debug mode.
+
+## WSGI Wrapper
+You may also use the WSGI wrapper to expose the metrics, like so:
+
+```
+from flask import Flask
+from flask_prometheus import monitor_app
+
+app = Flask(__name__)
+
+@app.route('/')
+def hello():
+    return 'Hello'
+
+app = monitor_app(app)
+app.run()
+```

flask_prometheus/__init__.py

@@ -1,9 +1,9 @@
-
 import time
 
-from prometheus_client import Counter, Histogram
-from prometheus_client import start_http_server
 from flask import request
+from prometheus_client import Counter, Histogram
+from prometheus_client import start_http_server, make_wsgi_app
+from werkzeug.wsgi import DispatcherMiddleware
 
 FLASK_REQUEST_LATENCY = Histogram('flask_request_latency_seconds', 'Flask Request Latency',
 				['method', 'endpoint'])
@@ -22,6 +22,18 @@ def after_request(response):
 
     return response
 
+
+def monitor_app(app, path="/metrics"):
+    app.before_request(before_request)
+    app.after_request(after_request)
+
+    prometheus_app = make_wsgi_app()
+
+    return DispatcherMiddleware(app, {
+        path: prometheus_app
+    })
+
+
 def monitor(app, port=8000, addr=''):
     app.before_request(before_request)
     app.after_request(after_request)