# Opencensus Prometheus integration for Erlang/BEAM #
Copyright (c) 2018 Ilya Khaprov <<i.khaprov@gmail.com>>.
__Version:__ 0.3.1
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> [Opencensus][Opencensus Erlang link]: Erlang stats collection and distributed tracing framework.
> [Prometheus.io][Prometheus Erlang link]: monitoring system and time series database client in Erlang.
## Using
Opencensus has trace and stats packages, trace package if for distributed tracing and
stats package is for backend-agnostic metrics collection.
This library implements a trace `reporter` for exporting spans duration as prometheus metrics and
a stats `exporter` for exporting metrics collected using Opencensus.
Example configuration:
```erlang
{opencensus, [
{reporter, {oc_reporter_sequential, [
{oc_reporter_zipkin, [
{url, "http://localhost:9411"},
{service_name, "service_name"}
]},
{oc_prometheus_reporter, [{type, histogram}, %% metric type
{name, span_histogram_seconds}, %% metric name, note the time unit
{buckets, [0, 1, 2]}]} %% histogram buckets with bounds in the time unit
]}},
{sampler, {oc_sampler_probability, [
{probability, 0.001} %% one in a thousand
]}}
]}
```
Since Prometheus uses push model you don't need to set up Opencensus stats exporter as usual.
Instead, this library provides `oc_stat_exporter_prometheus` which implements Prometheus collector interface.
```erlang
prometheus_registry:register_collector(oc_stat_exporter_prometheus)
```
## Other Prometheus and Opencensus Links
## Opencensus
- [Cowboy 2 Integration](https://github.com/deadtrickster/opencensus-cowboy)
- [Google Cloud Trace](https://github.com/tsloughter/oc_google_reporter)
### Prometheus
- [Cowboy1/2 Exporters and Cowboy2 instrumenter](https://hex.pm/packages/prometheus_cowboy)
- [Ecto Instrumenter](https://hex.pm/packages/prometheus_ecto)
- [Elixir client](https://github.com/deadtrickster/prometheus.ex)
- [Elixir plugs Instrumenters and Exporter](https://hex.pm/packages/prometheus_plugs)
- [Extatus - App to report metrics to Prometheus from Elixir GenServers](https://github.com/gmtprime/extatus)
- [Fuse plugin](https://github.com/jlouis/fuse#fuse_stats_prometheus)
- [Inets HTTPD Exporter](https://github.com/deadtrickster/prometheus_httpd)
- [OS process info Collector](https://hex.pm/packages/prometheus_process_collector) (linux, freebsd, macos)
- [Phoenix Instrumenter](https://hex.pm/packages/prometheus_phoenix)
- [RabbitMQ Exporter](https://github.com/deadtrickster/prometheus_rabbitmq_exporter).
## Contributing
Section order:
- Types
- Macros
- Callbacks
- Public API
- Deprecations
- Private Parts
Install the `git` pre-commit hook:
```bash
./bin/pre-commit.sh install
```
The pre-commit check can be skipped by passing `--no-verify` to `git commit`.
## License
MIT
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[Coveralls link]: https://coveralls.io/github/deadtrickster/opencensus_erlang_prometheus?branch=master
[Opencensus Erlang link]: https://github.com/census-instrumentation/opencensus-erlang
[Prometheus Erlang link]: https://github.com/deadtrickster/prometheus.erl
## Modules ##
<table width="100%" border="0" summary="list of modules">
<tr><td><a href="https://github.com/deadtrickster/opencensus-erlang-prometheus/blob/master/doc/oc_reporter_prometheus.md" class="module">oc_reporter_prometheus</a></td></tr>
<tr><td><a href="https://github.com/deadtrickster/opencensus-erlang-prometheus/blob/master/doc/oc_stat_exporter_prometheus.md" class="module">oc_stat_exporter_prometheus</a></td></tr></table>