Otelot

Export your Elixir app's metrics and logs to any OpenTelemetry backend over OTLP — without rewriting your instrumentation.

• Metrics: reuse the Telemetry.Metrics definitions you already have (Phoenix, Ecto, Oban, your own :telemetry events). Otelot aggregates them in-process and exports them as OTel sums, gauges and histograms.
• Logs: a :logger handler that batches log events and ships them as OTel log records, with trace/span correlation when the official tracing SDK is in use.

Otelot is a fork of otel_metric_exporter, which was used in production at Electric.

Installation

def deps do
  [
    {:otelot, "~> 0.5"}
  ]
end

Quickstart

Point Otelot at an OTLP/HTTP endpoint:

# config/runtime.exs
config :otelot,
  otlp_endpoint: "http://localhost:4318",
  resource: %{service: %{name: "my_app"}}

Export metrics by adding the exporter to your supervision tree, e.g. in the Telemetry module that Phoenix generates:

children = [
  {Otelot.MetricExporter, metrics: metrics(), export_period: :timer.seconds(30)}
]

Export logs by registering the handler:

# config/config.exs
config :my_app, :logger, [
  {:handler, :otel, Otelot.LogHandler, %{config: %{metadata: [:request_id]}}}
]

# lib/my_app/application.ex, in start/2
Logger.add_handlers(:my_app)

The standard OTEL_EXPORTER_OTLP_*, OTEL_SERVICE_NAME and OTEL_RESOURCE_ATTRIBUTES environment variables are honoured too.

Documentation

• Getting started — full setup, a local collector for experimenting, troubleshooting.
• Metrics — how Telemetry.Metrics types map to OTel, export semantics, differences from the official SDK.
• Configuration — all options and environment variables.

How it differs from the official OpenTelemetry SDK

Otelot trades API compliance for fitting into the existing Elixir ecosystem:

• Metrics are defined with Telemetry.Metrics, not the OTel Metrics API. No Views, no Exemplars, no link to traces.
• summary metrics and OTel's ExponentialHistogram are not supported.
• Transport is OTLP over HTTP with protobuf encoding; gRPC and HTTP/JSON are not supported.
• It doesn't do tracing. Use opentelemetry for that; the two work fine side by side.

Compatibility

Otelot requires Elixir 1.17+ and is tested in CI against:

It works with any OTLP/HTTP receiver: the OpenTelemetry Collector, Grafana Cloud, Honeycomb, Datadog, etc.

Development

mix deps.get
mix test
mix format --check-formatted

See CONTRIBUTING.md before opening an issue or a pull request.

Maintenance

Otelot is maintained by Oleksii Sholik on a best-effort basis. It follows semantic versioning; while it is on 0.x, minor releases may contain breaking changes, which are always called out in the changelog.

License

Apache 2.0, see LICENSE.