https://github.com/rubberduck203/ex_prometheus_logger
Elixir Logger Backend for Prometheus
https://github.com/rubberduck203/ex_prometheus_logger
elixir error-monitoring log-metrics log-monitoring prometheus
Last synced: about 1 year ago
JSON representation
Elixir Logger Backend for Prometheus
- Host: GitHub
- URL: https://github.com/rubberduck203/ex_prometheus_logger
- Owner: rubberduck203
- License: mit
- Created: 2018-11-08T01:49:22.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2018-11-10T16:05:10.000Z (over 7 years ago)
- Last Synced: 2025-01-28T13:52:39.996Z (over 1 year ago)
- Topics: elixir, error-monitoring, log-metrics, log-monitoring, prometheus
- Language: Elixir
- Size: 354 KB
- Stars: 1
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# ExPrometheusLogger
ExPrometheusLogger is a [custom Elixir logger backend](https://hexdocs.pm/logger/Logger.html#module-custom-backends).
It creates counters and increments them on logging events, providing easy insight into the number of warning & errors occuring in your applications.
![`rate(ex_logger[30s])`: Rate of increase per second of warnings and errors](img/rate.png)
## Installation
### mix.exs
```elixir
def deps do
[
{:prometheus_logger, git: "https://github.com/rubberduck203/ex_prometheus_logger.git", tag: "0.1.1"},
]
```
### Configuration
Just add the logger backend to your config
#### config.exs
```elixir
config :logger,
backends: [:console, Logger.Backends.Prometheus]
```
and ensure that `:prometheus` is started before `:logger`.
#### mix.exs
```elixir
def application do
[
# :prometheus *must* be started before :logger
extra_applications: [:prometheus, :logger]
]
end
```
Currently, the only supported configuration is the log level.
It defaults to `:warn`.
Setting or changing the base logger level has no effect on ExPrometheusLogger's level.
```
config :logger, Logger.Backends.Prometheus,
level: :warn
```
## Exposing Metrics
ExPrometheusLogger doesn't actually publish the metrics.
It just creates and increments [prometheus_ex counters](https://hexdocs.pm/prometheus_ex/Prometheus.Metric.Counter.html#content).
It's the user's responsibility to expose those metrics,
either by [exposing a `/metrics` endpoint](https://medium.com/@brucepomeroy/publishing-metrics-to-prometheus-from-elixir-bb70efcd6ec1)
or by using the [pushgateway](https://github.com/deadtrickster/prometheus-push).
See the [example](example/) directory for examples of how to use [pushgateway](example/pushgateway) and [Cowboy & Plug](example/cowboy) to publish the metrics.
## Alerting
The logger backend uses a `counter` to collect the number of times different level logging events have occured.
Because this is a counter, to set up an alert, it us recommended to use the [`rate()`](https://prometheus.io/docs/prometheus/latest/querying/functions/#rate) function to calculate the rate at which errors/warnings are *increasing* over a period of time.
```prometheus
rate(
ex_logger{level="error"}[1m]
)
```
See [example/rules.yml](example/rules.yml) for sample alerting rules.
There are times you may want to alert on a hard number of log messages.
That should be a relatively rare, but straight forward, use case.
## Roadmap
- [x] Provide examples for using
- [x] Pushgateway
- [x] Exposing a `/metrics` endpoint
- [ ] Use pushgateway automatically if `:prometheus, :pushgateway` config is present in app env.
- [ ] Publish on Hex
- [ ] Publish docs
- [ ] Travis CI build/release
- [ ] Custom labels?
- [ ] Take `:logger, :level` into consideration
- [ ] Leverage logger meta-data?