Here, we are using opentelemetry_exporter to export the traces to OpenTelemetry Collector. The collector in turn export the traces to Zipkin and Jaeger respectively.

Additionally, we also include the OpenTelemetry Collector and opentelemetry_exporter configuration to export the traces to external services like Honeycomb and Lightstep. 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:

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

Visit Zipkin at http://localhost:9411 and hit Run Query to look the the sample trace.
Visit Jaeger UI at http://localhost:16686, select demo under Service and click Find Trace to look at the sample trace.
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: