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mod_prometheus/README.markdown @ 4776:13e913471b75

mod_http_admin_api: Ensure freshness of metrics when in manual mode When in manual collection mode, as recommended for Prometheus, collection needs to be triggered manually, or they would be stale, possibly dating from the start of the server. This might vary per metric depending on how and when the metrics are gathered.
author Kim Alvefur <zash@zash.se>
date Thu, 18 Nov 2021 19:26:07 +0100
parent 4545:f4ab80f72d63
child 4790:bb66e87a3604
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---
labels:
- Statistics
summary: Implementation of the Prometheus protocol
...

Description
===========

This module implements the Prometheus reporting protocol, allowing you
to collect statistics directly from Prosody into Prometheus.

See the [Prometheus documentation][prometheusconf] on the format for
more information.

[prometheusconf]: https://prometheus.io/docs/instrumenting/exposition_formats/

Configuration
=============

mod\_prometheus itself doesn’t have any configuration option, but it
requires Prosody’s [internal statistics
provider](https://prosody.im/doc/statistics#built-in_providers) to be
enabled.  You may also want to change the default collection interval
to the one your statistics consumer is using. See below for more information.

```lua
statistics = "internal"
statistics_interval = 15 -- in seconds
```

::: {.alert .alert-warning}
**NOTE:** Make sure to put the statistics variables in the global section of
the configuration, **not** in a `VirtualHost` or `Component` section.  You can
use `prosodyctl check` if you are unsure and want to check your configuration.
:::

See also the documentation of Prosody’s [HTTP
server](https://prosody.im/doc/http), since Prometheus is an HTTP
protocol that is how you can customise its URL.  The default one being
http://localhost:5280/metrics

Scrape interval vs statistics_interval
--------------------------------------

The `statistics_interval` should be set to `"manual"` on trunk if and only
if you have a single Prometheus instance scraping Prosody. This will allow
the internal statistics gathering to run optimally.

If you have multiple instances scraping Prosody, set `statistics_interval`
to the scrape interval of Prometheus to avoid errors in rate calculations
and similar.

Future work will allow the use of `"manual"` with multiple Prometheus
instances and varying scrape intervals (stay tuned).

Compatibility
=============

  ------- -------------
  trunk   Works
  0.11    Works
  0.10    Works
  0.9     Does not work
  ------- -------------