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Function: logWithTrace()

@arolariu/website

@arolariu/website / instrumentation.server / logWithTrace

Function: logWithTrace()

logWithTrace(level, message, attributes?, renderContext?): void

Defined in: instrumentation.server.ts:1321

Emit structured logs correlated with distributed traces.

Provides JSON-formatted logging with automatic trace context injection. This enables correlation between logs and traces in observability platforms.

Parameters​

level​

LogLevel

Log level (debug, info, warn, error)

message​

string

Human-readable log message

attributes?​

Record<string, unknown>

Additional structured data to include in the log entry

renderContext?​

RenderContext

Returns​

void

Remarks​

  • Automatically includes trace ID and span ID when within an active span
  • Outputs JSON to stdout/stderr for structured log ingestion
  • Timestamps are ISO 8601 formatted
  • Use attributes for structured data instead of string interpolation
  • Logs are written to appropriate console stream based on level
  • Debug logs are only emitted in development mode

Examples​

// Basic logging with context
logWithTrace('info', 'User logged in', {
  'user.authenticated': true,
  'auth.method': 'clerk',
}, 'api');
// API route logging
await withSpan('api.user.create', async (span) => {
  logWithTrace('info', 'Creating user', {
    'http.method': 'POST',
    'http.route': '/api/users',
  }, 'api');

  try {
    const user = await createUser(data);
    logWithTrace('info', 'User created successfully', {
      userId: user.id,
    }, 'api');
  } catch (error) {
    logWithTrace('error', 'Failed to create user', {
      'error.type': error.constructor.name,
      'error.message': error.message,
      'error.handled': true,
    }, 'api');
  }
});
// Server component logging
logWithTrace('debug', 'Rendering user profile', {
  'next.render_context': 'server',
  'next.server_components': true,
}, 'server');
// Output format
{
  "timestamp": "2025-10-11T14:30:00.123Z",
  "level": "info",
  "message": "User logged in",
  "traceId": "1234567890abcdef",
  "spanId": "fedcba0987654321",
  "context": "api",
  "user.authenticated": true,
  "auth.method": "clerk"
}

See​

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