Kayla Reopelle: What Your Rails App Is Trying To Tell You

In this episode of On Rails, Robby is joined by Kayla Reopelle, a lead software engineer at New Relic, where she works on both the Ruby Agent and OpenTelemetry RubyGems. They explore what observability means for Rails developers—not just as a debugging tool, but as a way to build clearer, more reliable systems. Kayla explains OpenTelemetry's vendor-agnostic approach to instrumentation and shares practical ways to experiment with traces, metrics, and logs in both production and local development.

GitHub: https://github.com/kaylareopelle 

🧰 Tools & Libraries Mentioned

ActiveSupport::Notifications: Rails’ pub/sub API used for instrumentation.
AppSignal: Rails-friendly APM and error tracking.
AWS X-Ray: Distributed tracing for AWS services.
Datadog: Full-stack observability platform.
Elastics Profiling Spec: Donated profiling format for OpenTelemetry.
Grafana: Open-source dashboards and visualization.
Honeybadger : Error monitoring for Ruby apps.
Jaeger: Distributed tracing system (CNCF).
New Relic Ruby Agent: APM agent for Ruby and Rails.
ObservableGauge (OTel Metrics): Async gauge for snapshots like queue size.
OpenTelemetry Collector: Pipeline for receiving and exporting telemetry data.
OpenTelemetry Logger Bridge: Sends Ruby logger output to OTEL.
OpenTelemetry Ruby: Vendor-agnostic telemetry for Ruby.
OpenTelemetry Ruby SIG: Community group maintaining OTEL Ruby.
Prometheus: Metrics collection and storage.
Rack Middleware: Web middleware stack used in many Rails instrumentations.
Rails Structured Logging / Event Reporter: Structured logs built into Rails.
Semantic Logger: Structured logging for Ruby & Rails.
Stripe Ruby Gem: Payments client used as an instrumentation analogy.
UpDownCounter (OTel Metrics): Counter for tracking active jobs.

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On Rails is a podcast focused on real-world technical decision-making, exploring how teams are scaling, architecting, and solving complex challenges with Rails. 

On Rails is brought to you by The Rails Foundation, and hosted by Robby Russell of Planet Argon, a consultancy that helps teams modernize their Ruby on Rails applications.