# TelemetryMetricsMnesia
[](https://github.com/t0ha/telemetry_metrics_mnesia/actions/workflows/push.yml)
[](https://hex.pm/packages/telemetry_metrics_mnesia)
`Telemetry.Metrics` reporter and metrics backend based on Mnesia DB.
## Features
- Full compatibility with `Telemetry.Metrics` specification.
- Supports distribution between BEAM nodes.
- In-memory and persistant data storage modes.
- Custom metric aggregaaion support.
- Has no external non-beam dependences.
## Installation
Just add the reporter to your dependencies in `mix.exs`:
```elixir
defp deps do
[
{:telemetry_metrics_mnesia, "~> 0.1.0"}
]
end
```
## Configuration
You can configure optional cleanup process. Add the following to your `config.exs`:
```elixir
import Config
config :telemetry_metrics_mnesia,
# Timeout between cleanup process invocations in seconds, default 10.
cleanup_timeout: 10,
# Max telemetry events age to store in seconds (0 means infinity), default 0.
max_storage_time: 5
```
When `max_storage_time` is zero cleanup process doesn't start.
## Usage
To use it, start the reporter with the `start_link/1` function, providing it a list of
`Telemetry.Metrics` metric definitions:
```elixir
import Telemetry.Metrics
alias Telemetry.Metrics.Counter
alias Telemetry.Metrics.Distribution
alias Telemetry.Metrics.LastValue
alias Telemetry.Metrics.Sum
alias Telemetry.Metrics.Summary
TelemetryMetricsMnesia.start_link(
metrics: [
counter("http.request.count"),
sum("http.request.payload_size"),
last_value("vm.memory.total")
]
)
```
or put it under a supervisor:
```elixir
import Telemetry.Metrics
children = [
{TelemetryMetricsMnesia, [
metrics: [
counter("http.request.count"),
sum("http.request.payload_size"),
last_value("vm.memory.total")
]
]}
]
Supervisor.start_link(children, ...)
```
By default the reporter uses in-memory storage without distribution.
### Getting metrics values
There is a unified API for retrieving metrics data.
Use `TelemetryMetricsMnesia.fetch(metric_name, opts)` to do it:
```elixir
alias TelemetryMetricsMnesia, as: Metrics
# Simple metrics
%{Counter => request_count} = Metrics.fetch([:http, :request, :count])
%{Counter => request_count_per_minute} = Metrics.fetch([:http, :request, :count], granularity: [minites: 1])
%{Sum => total_requests_size} = Metrics.fetch([:http, :request, :payload_size])
%{Sum => request_size_per_second} = Metrics.fetch([:http, :request, :count], granularity: [:seconds, 1])
%{LastValue => total_memory} = Metrics.fetch([:vm, :memory, :total])
# Complex metrics
%{
Distribution => %{
median: median,
p75: p7_5,
p90: p9_0,
p95: p9_5,
p99: p99
}
} = TelemetryMetricsMnesia.fetch([:http, :request, :duration])
%{
Summary => %{
mean: avg,
variance: var,
standard_deviation: sd,
median: median,
count: count
}
} = TelemetryMetricsMnesia.fetch([:http, :request, :duration])
# Multiple metrics with the same name
%{
Distribution => %{
median: median,
p75: p7_5,
p90: p9_0,
p95: p9_5,
p99: p99
},
Summary => %{
mean: avg,
variance: var,
standard_deviation: sd,
median: median,
count: count
}
} = TelemetryMetricsMnesia.fetch([:http, :request, :duration])
# Metric with tags
# Strated as `counter("http.request.count", tags: [:endpoint, :code])`
%{
Counter => %{
%{endpoint: "/", code: 200} => app_requests_success,
%{endpoint: "/", code: 500} => app_requests_server_fail,
%{endpoint: "/api", code: 200} => api_requests_success
}
} = TelemetryMetricsMnesia.fetch([:http, :request, :counter])
```
## Copyright and License
TelemetryMetricsMnesia is copyright (c) 2023 Anton Shvein.
TelemetryMetricsMnesia source code is released under MIT license.
See [LICENSE](LICENSE) for more information.
