Prometheus Flask exporter with __main__

I want to use Prometheus Flask exporter with __main__.

This works fine by running env FLASK_APP=app.py flask run --port=80 --host=‘0.0.0.0’:

from flask import Flask
from prometheus_flask_exporter import PrometheusMetrics

app = Flask(__name__)
metrics = PrometheusMetrics(app)

app.debug = True

@app.route("/", methods=['GET'])
def index():
    return "hello world"

But I want to use my app in __main__, running python app.py.

from flask import Flask
from prometheus_flask_exporter import PrometheusMetrics

app = Flask(__name__)
metrics = PrometheusMetrics(app=None, path='/metrics')

app.debug = True

@app.route("/", methods=['GET'])
def index():
    return "hello world"

if __name__ == '__main__':
    metrics.init_app(app)
    app.run(host='0.0.0.0', port=80)

Here I get 400 on /metrics.

I got no clue how to init metrics correctly.

thx for helping klml

PS I asked this already stackoverflow.com, but got no answer.

[ampedandwired]

Can confirm that the debug flag seems to break things. If I put the following in app.py and run with python app.py then I see the metrics page successfully at http://127.0.0.1:5000/metrics

from flask import Flask
from prometheus_flask_exporter import PrometheusMetrics
app = Flask(__name__)
metrics = PrometheusMetrics(app=app)
app.run(debug=False)

But change debug=False to debug=True and I get a 404. This is with prometheus-flask-exporter==0.11.0.

[klml]

@rycus86 thx for your lightspeed responses;)

I tried DEBUG_METRICS and it suddenly worked. It even does not depend if DEBUG_METRICS is true or false. It only must be set. Vice versa, with no DEBUG_METRICS at all, I get “my” 404.

First I tried without DEBUG_METRICS and got a 404, but I got 200 be only setting DEBUG_METRICS.

root@ocpdevc001 [0] :/home/klml/python-ocp-demo
# echo $DEBUG_METRICS

root@ocpdevc001 [0] :/home/klml/python-ocp-demo
# python3 app.py 
 * Running on http://0.0.0.0:80/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 780-306-174
10.12.69.235 - - [04/Nov/2019 10:13:23] "GET /metrics HTTP/1.1" 404 -


root@ocpdevc001 [0] :/home/klml/python-ocp-demo
# export DEBUG_METRICS=false
root@ocpdevc001 [0] :/home/klml/python-ocp-demo
# python3 app.py 
 * Running on http://0.0.0.0:80/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 780-306-174
10.12.69.235 - - [04/Nov/2019 10:13:37] "GET /metrics HTTP/1.1" 200 -

So I got a workaround;)

Thx klml