OpenTelemetry Example Running Ruby v2.7.8 and Rails v6.0.6.1

Ensure you're on the correct Ruby version:

rbenv local 2.7.8

Install deps:

bundle install

Start server w/ ENV vars for configuration:

env OTEL_RESOURCE_ATTRIBUTES="highlight.project_id=YOUR_LD_SDK_KEY" OTEL_EXPORTER_OTLP_ENDPOINT="https://otel.observability.app.launchdarkly.com:4318" OTEL_TRACES_EXPORTER="otlp" rails server

Run in GitHub Codespaces

1. Create a new Codespace on this repo. It will auto-detect .devcontainer and build the container with Ruby 2.7 and Postgres.

2. After the container starts, dependencies and database will be prepared automatically. If needed, run:

bundle install && bundle exec rails db:prepare

3. Start Rails (port is forwarded automatically):

OTEL_RESOURCE_ATTRIBUTES="highlight.project_id=YOUR_LD_SDK_KEY" \
OTEL_EXPORTER_OTLP_ENDPOINT="https://otel.observability.app.launchdarkly.com:4318" \
OTEL_TRACES_EXPORTER="otlp" \
bundle exec rails server -b 0.0.0.0 -p 3000

Or use VS Code Tasks: “Rails: server”.

Database connection in Codespaces is configured via env vars in the devcontainer: DATABASE_HOST=db, DATABASE_USERNAME=postgres, DATABASE_PASSWORD=postgres.

Run locally with Docker

1. Build and start containers:

docker compose up --build

2. Visit http://localhost:3000

Environment is wired for Postgres inside Docker (db:5432). Override OTEL envs as needed:

docker compose run --rm -e OTEL_EXPORTER_OTLP_ENDPOINT=... -e OTEL_RESOURCE_ATTRIBUTES=... app bash