Flask-Prometheus

About

Out of the box, this flask extension makes it extremely easy to monitor your application using SoundCloud's Prometheus. For more on Prometheus, see their website.

This extension instruments every flask route and exports the following metrics:

• Histogram: <flask_request_latency_seconds> {'endpoint', 'method'}
• Summary: <flask_request_count> {'endpoint','method','http_status'}

Installation

pip install flask_prometheus

Basic Usage

Type the following into an interpreter:

from flask import Flask
from flask_prometheus import monitor 

app = Flask(__name__)

@app.route('/')
def hello():
    return 'Hello'

monitor(app, port=8000)
app.run()

Now, naviagate localhost:5000 a few times and then view metrics on localhost:8000 which should look like:

# HELP flask_request_count Flask Request Count
# TYPE flask_request_count counter
flask_request_count{endpoint="/",http_status="200",method="GET"} 4.0
# HELP flask_request_latency_seconds Flask Request Latency
# TYPE flask_request_latency_seconds histogram
flask_request_latency_seconds_bucket{endpoint="/",le="0.005",method="GET"} 4.0
flask_request_latency_seconds_bucket{endpoint="/",le="0.01",method="GET"} 4.0
flask_request_latency_seconds_bucket{endpoint="/",le="0.025",method="GET"} 4.0
flask_request_latency_seconds_bucket{endpoint="/",le="0.05",method="GET"} 4.0
flask_request_latency_seconds_bucket{endpoint="/",le="0.075",method="GET"} 4.0
flask_request_latency_seconds_bucket{endpoint="/",le="0.1",method="GET"} 4.0
flask_request_latency_seconds_bucket{endpoint="/",le="0.25",method="GET"} 4.0
flask_request_latency_seconds_bucket{endpoint="/",le="0.5",method="GET"} 4.0
flask_request_latency_seconds_bucket{endpoint="/",le="0.75",method="GET"} 4.0
flask_request_latency_seconds_bucket{endpoint="/",le="1.0",method="GET"} 4.0
flask_request_latency_seconds_bucket{endpoint="/",le="2.5",method="GET"} 4.0
flask_request_latency_seconds_bucket{endpoint="/",le="5.0",method="GET"} 4.0
flask_request_latency_seconds_bucket{endpoint="/",le="7.5",method="GET"} 4.0
flask_request_latency_seconds_bucket{endpoint="/",le="10.0",method="GET"} 4.0
flask_request_latency_seconds_bucket{endpoint="/",le="+Inf",method="GET"} 4.0
flask_request_latency_seconds_count{endpoint="/",method="GET"} 4.0
flask_request_latency_seconds_sum{endpoint="/",method="GET"} 0.0010027885437011719

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()