bianhaifeng789-hue/skills-experimental/diag-logger-wrapper

Diag Logger Wrapper Pattern

Source

Claude Code: utils/telemetry/logger.ts (ClaudeCodeDiagLogger)

Pattern

OpenTelemetry DiagLogger interface wrapper - error/warn only, info/debug silenced.

Code Example

import type { DiagLogger } from '@opentelemetry/api'

export class ClaudeCodeDiagLogger implements DiagLogger {
  error(message: string, ..._: unknown[]) {
    logError(new Error(message))
    logForDebugging(`[3P telemetry] OTEL diag error: ${message}`, { level: 'error' })
  }

  warn(message: string, ..._: unknown[]) {
    logError(new Error(message))
    logForDebugging(`[3P telemetry] OTEL diag warn: ${message}`, { level: 'warn' })
  }

  info(_message: string, ..._args: unknown[]) {
    return  // Silenced - no logging
  }

  debug(_message: string, ..._args: unknown[]) {
    return  // Silenced - no logging
  }

  verbose(_message: string, ..._args: unknown[]) {
    return  // Silenced - no logging
  }
}

// Usage in instrumentation.ts:
diag.setLogger(new ClaudeCodeDiagLogger(), DiagLogLevel.ERROR)

Key Concepts

1. DiagLogger Interface: OpenTelemetry diagnostic logger
2. Error/Warn Only: Only error/warn emit to logError + logForDebugging
3. Info/Debug/Verbose Silenced: No logging for lower levels
4. Dual Logging: logError for error tracking + logForDebugging for telemetry tag
5. DiagLogLevel: ERROR level suppresses warn/info/debug/verbose

Benefits

• OTel diagnostics visible in error logs
• Lower levels silenced to reduce noise
• 3P telemetry tag for filtering

When to Use

• OTel SDK diagnostic configuration
• Third-party library logging control
• Error visibility without verbosity

Related Patterns

• OTel Instrumentation Bootstrap (instrumentation.ts)
• Error Log Sink (errorLogSink.ts)
• Debug Logging (debug.ts)