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# Otel

Pure Elixir, [OpenTelemetry](https://opentelemetry.io/)-compatible

## Features

- **Signals**
  - Traces
  - Metrics
  - Logs
- **Propagators**
  - W3C TraceContext
  - W3C Baggage
- **Exporters**
  - OTLP/HTTP (Protobuf)
- **Integrations**
  - `:logger` bridge
  - `:telemetry` bridge

## Requirements

- Elixir `~> 1.18`
- Erlang/OTP `~> 26.2`

## Compatibility

| Component | Version |
|---|---|
| OpenTelemetry Specification | `v1.55.0` (Stable signals only) |
| OpenTelemetry Protocol (OTLP) | `v1.10.0` |
| W3C Trace Context | Level 2 (REC) |
| W3C Baggage | OTel Stable Baggage Propagator wire format |

## Installation

Add `:otel` to `deps` in `mix.exs`:

```elixir
def deps do
  [
    {:otel, "~> 0.3.0"}
  ]
end
```

## Configuration

### SDK

```elixir
# config/config.exs
config :otel, otp_app: :my_app, req_options: []
```

### Logs

`:logger` bridge:

```elixir
# config/config.exs
config :kernel,
  logger: [
    {:handler, :otel, Otel.LoggerHandler, %{}}
  ]
```

### Metrics

`:telemetry` bridge (in your supervision tree):

```elixir
# lib/my_app/application.ex
children = [
  {Otel.TelemetryReporter, metrics: [...]}
]
```

## How-to

- [Trace](docs/trace.md) — span lifecycle, attributes, events, status, exceptions.

## License

Released under the [MIT License](LICENSE).