grpc/grpc-go · error

failed to start logging: %v

Error message

failed to start logging: %v

What it means

A wrapper returned by Start() when startLogging(ctx, config) fails. This is the Cloud Logging subsystem initialization (binary log sink setup). OpenCensus tracing/metrics have already succeeded by this point, but the logging collector could not be installed; Start() rolls back everything via the deferred End().

Source

Thrown at gcp/observability/observability.go:76

	if err = ensureProjectIDInObservabilityConfig(ctx, config); err != nil {
		return err
	}

	// Cleanup any created resources this function created in case this function
	// errors.
	defer func() {
		if err != nil {
			End()
		}
	}()

	// Enabling tracing and metrics via OpenCensus
	if err = startOpenCensus(config); err != nil {
		return fmt.Errorf("failed to instrument OpenCensus: %v", err)
	}

	if err = startLogging(ctx, config); err != nil {
		return fmt.Errorf("failed to start logging: %v", err)
	}

	// Logging is controlled by the config at methods level.
	return nil
}

// End is the clean-up API for gRPC Observability plugin. It is expected to be
// invoked in the main function of the application. The suggested usage is
// "defer observability.End()". This function also flushes data to upstream, and
// cleanup resources.
//
// Note: this method should only be invoked once.
func End() {
	stopLogging()
	stopOpenCensus()
}

View on GitHub (pinned to 03255a9237)

Solutions

1. Read the wrapped error to determine whether the failure is auth, network, or config parsing.
2. Provide valid Application Default Credentials with the Logging Writer role.
3. If you only need tracing/metrics, disable the cloud_logging section in the config to bypass logging init.
4. Whitelist the Cloud Logging API endpoint in your firewall/proxy egress rules.

Example fix

// before
config: {"cloud_logging":{},"cloud_trace":{},"cloud_monitoring":{}}
// after (disable logging if you cannot satisfy its auth/egress requirements)
config: {"cloud_trace":{"sampling_rate":0.5},"cloud_monitoring":{}}

// Pre-flight: only enable cloud_logging if a Cloud Logging client can be built.
// (There is no public pre-check API; gate via config instead.)
if !loggingEnabled {
    config.CloudLogging = nil // avoid the failing path entirely
}

if err := observability.Start(ctx); err != nil {
    if strings.Contains(err.Error(), "failed to start logging") {
        // Retry with cloud_logging disabled so trace/metrics still work.
        log.Printf("disabling cloud_logging due to init failure: %v", err)
    }
}

When it happens

Trigger: Enabling cloud_logging in the config while the environment cannot supply a usable Cloud Logging client (missing/invalid credentials, unreachable logging endpoint, bad project). Passing a config whose logging method filters are malformed.

Common situations: Local dev machine without GCP credentials but with cloud_logging enabled; restrictive network egress rules blocking logging.googleapis.com; service account missing roles/logging.logWriter.

Related errors

• unable to create CloudLogging exporter: %v
• failed to instrument OpenCensus: %v
• invalid method string: %v, err: %v
• error in clientRPCEvent method: %v
• error in serverRPCEvent method: %v

AI-assisted analysis of grpc/grpc-go@03255a9237 (2026-08-07). Data as JSON: /api/errors/57818c140066ef98. Report an issue: GitHub.