Open Telemetry

Introduction

This is a quick page about open telemetry which I came across doing the Effect_TS.

Four things

Four things must ye know about Open Telemetry

• Traces - Spans
• Metrics - Performances, counts etc
• Logs - No Explanation required
• Baggage - contextual information we want to pass from span to span

This is an example of a trace with spans.

Trace: "User logs in"
├── Span: "Frontend sends login request"
├── Span: "API receives request"
│   ├── Span: "Validate credentials"
│   └── Span: "Query user DB"

Other Terms

• OTLP - Open Telemetry Protocol Sent over gRPC or HTTP.
• Collector - Own Service to accept data and push it out
• Instrumentation - How you make the data. Some frameworks like expressJS, effectTS have automatic but you can use a OpenTelemetry SDK

Configuring Collector

There are six things you configure in a collector

• Receivers - How is how you collector takes in data
• Processors - Cleansing, Transform
• Extensions - Extra things, e.g. health monitor
• Exporters - Push data out, e.g Loki, Prometheus
• Pipelines - The path that telemetry data—traces, metrics, or logs—follows from ingestion to export
• Connectors - Can export data from one pipeline and feed it into another

connectors:
  spanmetrics:

service:
  pipelines:
    traces:
      receivers: [otlp]
      exporters: [spanmetrics]

    metrics:
      receivers: [spanmetrics]
      exporters: [prometheus]

Example with Node

npm install @opentelemetry/sdk-node \
  @opentelemetry/api \
  @opentelemetry/auto-instrumentations-node \
  @opentelemetry/sdk-metrics \
  @opentelemetry/sdk-trace-node