nestjs-observability

name	nestjs-observability
description	Structured logging (Pino) and Prometheus metrics. Use when adding structured logging with Pino or Prometheus metrics to NestJS services. (triggers: main.ts, **/*.module.ts, nestjs-pino, Prometheus, Logger, reqId)

Observability Standards

Priority: P1 (OPERATIONAL)

Logging, monitoring, and observability patterns for production applications.

• Standard: Use nestjs-pino for high-performance JSON logging.
  • Why: Node's built-in console.log is blocking and unstructured.
• Configuration:
  • Redaction: Mandatory masking of sensitive fields (password, token, email).
  • Context: Always inject Logger and set the context (LoginService).

Tracing (Correlation)

• Request ID: Every log line must include a reqId (Request ID).
  • nestjs-pino handles this automatically using AsyncLocalStorage.
  • Propagation: Pass x-request-id to downstream microservices/database queries key to trace flows.

API Overhead & Database Benchmarking

• Execution Bucket Strategy: When performance profiling is enabled, utilize global interceptors combined with AsyncLocalStorage to split and expose latency into logical buckets.
• Headers: Expose the metrics via HTTP Headers on the response for immediate feedback during development or testing: