# Phoenix + Ecto OpenTelemetry Example

This is a example repository that demo how to setup OpenTelemetry for Phoenix application
with [`opentelemetry_phoenix`][0] and [`opentelemetry_ecto`][1].

Here, we are using [`opentelemetry_exporter`][2] to export the traces to [
OpenTelemetry Collector][3]. The collector in turn export the traces to [Zipkin][4] and [
Jaeger][5] respectively.

Additionally, we also include the OpenTelemetry Collector and
`opentelemetry_exporter` configuration to
export the traces to external services like [Honeycomb](https://www.honeycomb.io/) and
[Lightstep](https://lightstep.com/). Do remember to update the `.env` file to
include your crendentials if you're doing so.

## Getting Stated

By default, we only configure our OpenTelemetry collector to export traces to
the local Zipkin and Jaeger.

Assuming you already have Docker and Docker Compose installed:

1. Run `docker compose up -d` to start the Phoenix application, PostgreSQL,
   OpenTelemetry Collector, Zipkin and Jaeger.
2. Run deps get and ecto setup:
   ```
   mix deps.get, ecto.setup
   ```
3. Start phoenix `OTEL_SERVICE_NAME=demo iex -S mix phx.server`

4. Browse to http://localhost:4000. Additionally, you can:

- Visit http://localhost:4000/posts to see how it works for Phoenix HTML
- Visit http://localhost:4000/users to see how it works for Phoenix LiveView

5. Visit Zipkin at http://localhost:9411 and hit `Run Query` to look the the sample trace.
6. Visit Jaeger UI at http://localhost:16686, select `demo` under Service and click `Find Trace` to
   look at the sample trace.
7. Run `docker compose down` to destroy the created resources.

## Different ways to export traces

In general, there are 2 ways you can export your OpenTelemetry traces.

- Export to OpenTelemetry Collector, which can then be configured to export to
  external services.

  ```
  Application --> OpenTelemetry Collector --> Zipkin
                                      |-----> Jaeger
  ```

- Export directly to external services that accept OTLP protocol.

  ```
  Application --> External Service
  ```

For exporting to external services, be sure to checkout their
documentation first. For example:

- [OpenTelemetry | Honeycomb](https://docs.honeycomb.io/getting-data-in/opentelemetry/)
- [OpenTelemetry Collector | Honeycomb](https://docs.honeycomb.io/getting-data-in/opentelemetry/otel-collector/)
- [Send Telemetry Data via OTLP/HTTP | Lightstep Learning Portal](https://docs.lightstep.com/docs/send-otlp-over-http-to-lightstep)
- [Already Using OpenTelemetry Collectors? | Lightstep Learning Portal](https://docs.lightstep.com/docs/already-using-collectors)
- [OpenTelemetry quick start | New Relic Documentation](https://docs.newrelic.com/docs/more-integrations/open-source-telemetry-integrations/opentelemetry/opentelemetry-quick-start)

[0]: https://hex.pm/packages/opentelemetry_phoenix
[1]: https://hex.pm/packages/opentelemetry_ecto
[2]: https://hex.pm/packages/opentelemetry_exporter
[3]: https://github.com/open-telemetry/opentelemetry-collector/
[4]: https://zipkin.io/
[5]: https://www.jaegertracing.io/