Skill: logging-observability

What I do

I provide expertise in implementing structured logging, tracing, and metrics to ensure system observability. I focus on creating a clear, actionable data trail that allows for rapid debugging and performance analysis in production environments.

When to use me

• When designing a new service's logging strategy
• When instrumenting code with distributed tracing spans
• When adding metrics to track business-critical KPIs or system health
• When debugging complex, distributed issues that span multiple services

Core principles

1. Structure over prose: Use structured formats like JSON to make logs easily searchable and machine-readable.
2. Actionability: Every log message and metric should have a clear purpose. Avoid noise that obscures real issues.
3. Context is king: Include correlation IDs, request IDs, and relevant metadata (e.g., user ID, tenant ID) in every log entry.
4. The three pillars: Combine logs (discrete events), traces (request flow), and metrics (aggregates) for a complete view of system health.

Patterns & examples

Structured logging (JSON):

{
  "level": "info",
  "ts": "2026-02-22T21:00:00Z",
  "msg": "processed order",
  "order_id": "ORD-123",
  "user_id": "USR-456",
  "duration_ms": 150,
  "correlation_id": "CORR-789"
}

Log levels guide:

• DEBUG: Verbose information for development and troubleshooting.
• INFO: General operational events (e.g., service started, request completed).
• WARN: Unexpected but non-critical events that might require attention.
• ERROR: Critical failures that require immediate investigation.

Distributed tracing: Use OpenTelemetry to start spans at the beginning of a request and inject the context into downstream calls. This allows you to visualize the entire lifecycle of a request across multiple services.

Metrics types:

• Counters: For events that only increase (e.g., total requests, error count).
• Gauges: For values that go up and down (e.g., current memory usage, active connections).
• Histograms: For distributions of values (e.g., request latency, payload size).

Anti-patterns to avoid

• ❌ Log noise: Logging every trivial operation at the INFO level. This increases storage costs and makes finding real issues harder.
• ❌ Sensitive data in logs: Never log passwords, PII, or secrets. Always scrub or mask sensitive fields.
• ❌ Missing correlation IDs: Logs without a way to link them across services are nearly useless in distributed systems.
• ❌ Ignoring metrics: Relying solely on logs for health monitoring. Use metrics for real-time alerting and dashboards.

KB Reference

~/vaults/baphled/3. Resources/Knowledge Base/AI Development System/Skills/DevOps-Operations/Logging Observability.md

Related skills

• devops: For infrastructure and deployment considerations
• automation: For setting up alerting based on metrics and logs
• security: For ensuring logging practices meet compliance and data privacy standards
• performance: For using traces and metrics to identify and fix bottlenecks