Prometheus support

[runningman84]

It would be cool if appdaemon would expose some stats using the prometheus format.

[Odianosen25]

Hello @runningman84,

Can you kindly expand on what you are saying?

Kind regards

[runningman84]

a prometheus endpoint for appdaemon would allow us to monitor if the connection to home-assistant is working and how to apps are performing...

[acockburn]

The dev version of AD currently has a new admin interface, and as part of that, a number of internal data structures are exposed as entities and can be queried via the new REST interface. I am not familiar with Prometheus, but if it is capable of making arbitary REST calls to gather info, this could be made to work with some effort on the Prometheus side.

[runningman84]

Added Prometheus support in a python app can be done quite easily: https://github.com/prometheus/client_python/blob/master/README.md

[ReneTode]

it isnt that easy as they suggest. AD already starts a server, adding a server the way they suggest will start up a second server on another port, which can go wrong easily. they dont tell what kind of server is started and how.

so to add this there has to be a lot of research done and a lot of testing. there must also be an option in the appdaemon.yaml created so people can chose the option (you dont want all users to startup a second server by default, if they dont use it)

I dont see anything about SSL options or even a password that needs to be set. so its not a very secure thing to add.

that all said, combined with the fact that the new admin interface probably will give a lot of info that you want, i do advice against it, unless there is a real need and a lot of research done, and safety options are included.

if you are not running hassio, then you could add it yourself. if you are running hassio, then you did chose a platform that protects you from yourself and you dont want anyone to add unsafe parts in your programs.

[acockburn]

I'll leave this under consideration, but it's not a high priority for now. If you want to get this into the product more quickly, a Pull Request would be gratefully accepted.

[esev]

One other thing that makes this tricky is that the prometheus_client library does not allow for registering a metric more than once. That doesn't play nicely with AppDaemon's module reloading feature.

I was looking for a way to expose metrics from within my AppDeamon Apps, and implemented some basic Prometheus support within an AppDeamon app. It makes a best-effort to support module reloading. It uses register_route to export the metrics from the built-in web server (at /app/prometheus). And it exposes a few common metrics:

• appdeamon_info: Current version of AppDeamon
• appdaemon_app_active: 1.0 if the app is active, 0.0 otherwise.
• appdaemon_module_exceptions_total: Count of the number of unhandled exceptions that occur within a module.

https://gist.github.com/esev/3a7f48b37ba0b54b90efcd9b123f8f34

You'll need a requirements.txt file that includes prometheus-client to use this App. I don't intend to provide support for this App, but feel free to use it if it helps.