Example on how to expose metrics in a flask app #297
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README.md
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| @app.route("/metrics") | ||
| def metrics(): | ||
| return Response(generate_latest(), content_type=CONTENT_TYPE_LATEST) |
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This doesn't pull in all the other logic and endpoint should have. Can you reuse one of the ones that handles this for you?
README.md
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| @app.route("/metrics") | ||
| def metrics(): | ||
| r = core.REGISTRY |
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I don't want this logic duplicated here, I want you to use one of the existing functions for it. This code will change over time, and copy&pasted code in user applications won't get updated.
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Do you mean using like so?
from prometheus_client import REGISTRY
def metrics():
r = REGISTRYIf not, I'm probably missing the point. In my initial implementation I was hoping/expecting to find a clean function that returns a response having parsed out the parameters and done its magic. A new public api could be added that does something like this
def generate_latest(registry=core.REGISTRY, query_string=None)
"""Generate the latest metrics taking the query string into account"""
metrics_subset = parse_qs(query_string).get('name[]') if query_string is not None else None
if metrics_subset:
r = r.restricted_registry(metrics_subset)
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No, I mean reusing something like MetricsHandler that does all the http stuff.
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Since flask's response is a uwsgi application, I'll try to see how I can reuse make_wsgi_app as is.
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@brian-brazil I think the example should be good to go now.
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README.md
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| #### WSGI | ||
| #### Flask | ||
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| To use prometheus with [flask](http://flask.pocoo.org/) we need to serve metrics through a promethues wsgi application. This can be achieved using [flask's application dispatching|http://flask.pocoo.org/docs/latest/patterns/appdispatch/]. Below is a working example. |
README.md
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| ``` | |||
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| #### WSGI | |||
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Wsgi should stay first
README.md
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| return "Hello world !!" | ||
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| # Expose some basic metrics of the application | ||
| REQUEST_LATENCY = Histogram('request_latency_seconds', 'API Request Latency', ['method', 'endpoint']) |
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Keep this minimal, just enough to expose metrics at all like in the other examples.
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README.md
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| @@ -280,6 +280,34 @@ from prometheus_client import start_wsgi_server | |||
| start_wsgi_server(8000) | |||
| ``` | |||
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| #### Flask | |||
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| To use prometheus with [flask](http://flask.pocoo.org/) we need to serve metrics through a promethues wsgi application. This can be achieved using [flask's application dispatching](http://flask.pocoo.org/docs/latest/patterns/appdispatch/). Below is a working example. | |||
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Flask Prometheus WSGI
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Not sure I understand this comment
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Proper nouns should be capitalised.
README.md
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| }) | ||
| ``` | ||
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| To test this example, save the above snippet in a `myapp.py` file and run the command below |
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We mention filenames before the relevant example.
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README.md
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| @@ -280,6 +280,36 @@ from prometheus_client import start_wsgi_server | |||
| start_wsgi_server(8000) | |||
| ``` | |||
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| #### Flask | |||
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| To use Prometheus with [Flask](http://flask.pocoo.org/) we need to serve metrics through a Promethues WSGI application. This can be achieved using [Flask's application dispatching](http://flask.pocoo.org/docs/latest/patterns/appdispatch/). Below is a working example. | |||
Signed-off-by: Evans Mungai <mbuevans@gmail.com>
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Thanks! |
I'm working on a flask application that needs to expose metrics to prometheus. It was not very clear how that could be done without reading the code. This PR updates the README with a simple example of doing so. Hopefully it saves someone some time of trying to figure that out.
@brian-brazil