packrat-rails

To turn it off, set PACKRAT_DISABLED=1. The app then boots as if the gem were not installed.

OpenTelemetry for Rails, configured to send traces, logs and exceptions to Packrat with one key.

bundle add packrat-rails
bin/rails generate packrat --ingest-key=packrat_ingest_…
bin/rails server

The generator creates config/initializers/packrat.rb with the ingest key from your Packrat setup page:

Packrat.configure do |config|
  config.ingest_key = ENV.fetch("PACKRAT_INGEST_KEY", "packrat_ingest_…")
end

An ingest key can only send data, so you can commit the file. To keep the key out of the repository, run the generator without --ingest-key and set PACKRAT_INGEST_KEY where the app runs.

The generator also turns on the Packrat plugin for Claude Code in .claude/settings.json. Commit the file, and everyone who opens Claude Code in the repository and trusts the folder gets the plugin. If the file exists, the generator adds the plugin and keeps the rest. To leave the file alone, pass --no-claude-code.

On boot the gem writes one line to the Rails log. It names the service and environment the app reports under:

Packrat: sending traces and logs for shop/production to https://ingest.packrat.sh (rack, action_pack, active_job, active_record, net_http, pg, logger)

The ingest key and the ingest URL are the only settings in Packrat.configure. Everything else is an environment variable.

The instrumentations are rack, action_pack, action_view, active_job, active_record, net_http, pg, mysql2, sidekiq, redis, aws_sdk, concurrent_ruby, rake and logger. One for a library that is not in the app installs nothing. PACKRAT_OTEL_INSTRUMENTATIONS=faraday,-action_view adds Faraday (with opentelemetry-instrumentation-faraday in the Gemfile) and removes Action View. action_mailer and active_storage cannot be added: they must load before boot ends.

The service name is OTEL_SERVICE_NAME, else service.name in OTEL_RESOURCE_ATTRIBUTES, else the app's module name (Shop::Application is shop). The environment is Rails.env unless OTEL_RESOURCE_ATTRIBUTES names one. The version is BUILD_COMMIT, HEROKU_SLUG_COMMIT or SOURCE_VERSION. The instance is DYNO, else the host name. A standard OTEL_* variable that is set always wins.

The gem does nothing in the test environment.

• Nothing else: the gem configures OpenTelemetry.
• Your own OpenTelemetry setup: the gem leaves it as it is and adds a second exporter, to Packrat. If your exporter already sends to Packrat, it adds nothing.
• Sentry: both run. The gem does not touch Sentry.
• Datadog's tracer: the gem does nothing. Dual-ship from the Datadog Agent instead: https://packrat.sh/docs/datadog