grpc/grpc-go · error

error parsing observability config: %v

Error message

error parsing observability config: %v

What it means

unmarshalAndVerifyConfig could not json.Unmarshal the raw config bytes into the internal config struct. This is a structural JSON error in the observability config supplied via GRPC_GCP_OBSERVABILITY_CONFIG (env) or the file pointed to by GRPC_GCP_OBSERVABILITY_CONFIG_FILE. Distinct from 214 (which is field-validation failure) and 215 (sampling rate).

Source

Thrown at gcp/observability/config.go:114

		if err := validateLogEventMethod(clientRPCEvent.Methods, clientRPCEvent.Exclude); err != nil {
			return fmt.Errorf("error in clientRPCEvent method: %v", err)
		}
	}
	for _, serverRPCEvent := range config.CloudLogging.ServerRPCEvents {
		if err := validateLogEventMethod(serverRPCEvent.Methods, serverRPCEvent.Exclude); err != nil {
			return fmt.Errorf("error in serverRPCEvent method: %v", err)
		}
	}
	return nil
}

// unmarshalAndVerifyConfig unmarshals a json string representing an
// observability config into its internal go format, and also verifies the
// configuration's fields for validity.
func unmarshalAndVerifyConfig(rawJSON json.RawMessage) (*config, error) {
	var config config
	if err := json.Unmarshal(rawJSON, &config); err != nil {
		return nil, fmt.Errorf("error parsing observability config: %v", err)
	}
	if err := validateLoggingEvents(&config); err != nil {
		return nil, fmt.Errorf("error parsing observability config: %v", err)
	}
	if config.CloudTrace != nil && (config.CloudTrace.SamplingRate > 1 || config.CloudTrace.SamplingRate < 0) {
		return nil, fmt.Errorf("error parsing observability config: invalid cloud trace sampling rate %v", config.CloudTrace.SamplingRate)
	}
	logger.Infof("Parsed ObservabilityConfig: %+v", &config)
	return &config, nil
}

func parseObservabilityConfig() (*config, error) {
	if f := envconfig.ObservabilityConfigFile; f != "" {
		if envconfig.ObservabilityConfig != "" {
			logger.Warning("Ignoring GRPC_GCP_OBSERVABILITY_CONFIG and using GRPC_GCP_OBSERVABILITY_CONFIG_FILE contents.")
		}
		content, err := os.ReadFile(f)
		if err != nil {

View on GitHub (pinned to 03255a9237)

Solutions

1. Run the config through `jq -e .` (or `python -m json.tool`) to find the exact syntax error.
2. Ensure the contents are JSON, not YAML; convert with `yq -o=json` if needed.
3. Construct the config from a Go struct and json.Marshal it to guarantee validity.

Example fix

// before (env value)
GRPC_GCP_OBSERVABILITY_CONFIG='{ "project_id": "p", "cloud_logging": { "client_rpc_events": [], } }' // trailing comma

// after
GRPC_GCP_OBSERVABILITY_CONFIG='{ "project_id": "p", "cloud_logging": { "client_rpc_events": [] } }'

func validObservabilityJSON(b []byte) error {
    var raw map[string]any
    return json.Unmarshal(b, &raw)
}

cfg, err := parseObservabilityConfig()
if err != nil { return fmt.Errorf("observability config parse: %w", err) }

When it happens

Trigger: Malformed JSON: trailing comma, unquoted keys, single quotes, comments, or unknown fields combined with DisallowUnknownFields-style strictness. The error happens before any field validation runs.

Common situations: Hand-editing the env var with a typo; YAML mistakenly used in place of JSON; trailing comma from a templating system; an unclosed brace after appending a section.

Related errors

• error reading observability configuration file %q: %v
• invalid method string: %v, err: %v
• error in clientRPCEvent method: %v
• error in serverRPCEvent method: %v
• error parsing observability config: invalid cloud trace samp

AI-assisted analysis of grpc/grpc-go@03255a9237 (2026-08-07). Data as JSON: /api/errors/8291c3100b3a8bbf. Report an issue: GitHub.