Add support for gcp error reporting

cmd/example/main.go

@@ -24,11 +24,13 @@ func main() {
 		log.EnvLogScopeLevel,
 		log.EnvLogSamplingInitial,
 		log.EnvLogSamplingThereafter,
+		log.EnvLogStackTraceLevel,
 	} {
 		config = append(config, log.String(k, os.Getenv(k)))
 	}
 	l.Info("configuration", config...)
 
 	// sample message
 	l.Warn("hello world!", log.Time("now", time.Now()))
+	l.Error("hello world!", log.Time("now", time.Now()))
 }

init.go

@@ -48,6 +48,10 @@ var (
 	//
 	// Defaults to 100 - set explicitly to 0 or -1 to disable.
 	EnvLogSamplingThereafter = "SRC_LOG_SAMPLING_THEREAFTER"
+	// EnvLogStackTraceLevel is a key of the environment variable that can be used to set
+	// the log level to include stack traces on.
+	// Default does not include stack traces on any level.
+	EnvLogStackTraceLevel = "SRC_LOG_STACKTRACE_LEVEL"
 )
 
 type Resource = otelfields.Resource
@@ -94,7 +98,13 @@ func Init(r Resource, s ...Sink) *PostInitCallbacks {
 
 	// Init the logger first, so that we can log the error if needed, before dealing with
 	// sink builder errors
-	sync := globallogger.Init(r, currentDevMode, cores)
+	loggerOption := globallogger.LoggerOption{
+		Development: currentDevMode,
+	}
+	if os.Getenv(EnvLogStackTraceLevel) != "" {
+		loggerOption.StackTraceLevel = Level(os.Getenv(EnvLogStackTraceLevel)).Parse()
+	}
+	sync := globallogger.Init(r, loggerOption, cores)
 
 	if sinksBuildErr != nil {
 		// Log the error

internal/encoders/config.go

@@ -53,9 +53,10 @@ var GCPConfig = zapcore.EncoderConfig{
 	// These don't really have an equivalent in the OT spec, and we can't stick it under
 	// Attributes because they are top-level traits in Zap, so we just capitalize them and
 	// hope for the best.
-	CallerKey:     "Caller",
-	FunctionKey:   "Function",
-	StacktraceKey: "Stacktrace",
+	CallerKey:   "Caller",
+	FunctionKey: "Function",
+	// https://cloud.google.com/error-reporting/docs/formatting-error-messages#log-error
+	StacktraceKey: "stack_trace",
 
 	// Defaults
 	LineEnding:     zapcore.DefaultLineEnding,

internal/globallogger/globallogger.go

@@ -41,10 +41,10 @@ func Get(safe bool) *zap.Logger {
 
 // Init initializes the global logger once. Subsequent calls are no-op. Returns the
 // callback to sync the root core.
-func Init(r otelfields.Resource, development bool, sinks []zapcore.Core) func() error {
+func Init(r otelfields.Resource, opt LoggerOption, sinks []zapcore.Core) func() error {
 	globalLoggerInit.Do(func() {
-		devMode = development
-		globalLogger = initLogger(r, development, sinks)
+		devMode = opt.Development
+		globalLogger = initLogger(r, opt, sinks)
 		initialized.Store(true)
 	})
 	return globalLogger.Sync
@@ -62,6 +62,11 @@ type forceSyncer struct {
 	core zapcore.Core
 }
 
+type LoggerOption struct {
+	Development     bool
+	StackTraceLevel zapcore.Level
+}
+
 var _ zapcore.CheckWriteHook = &forceSyncer{}
 
 // OnWrite calls sync on the underlying core and then calls os.Exit(1).
@@ -71,14 +76,14 @@ func (f *forceSyncer) OnWrite(_ *zapcore.CheckedEntry, _ []zapcore.Field) {
 	os.Exit(1)
 }
 
-func initLogger(r otelfields.Resource, development bool, sinks []zapcore.Core) *zap.Logger {
+func initLogger(r otelfields.Resource, opt LoggerOption, sinks []zapcore.Core) *zap.Logger {
 	internalErrsSink, err := stderr.Open()
 	if err != nil {
 		panic(err.Error())
 	}
 
 	options := []zap.Option{zap.ErrorOutput(internalErrsSink), zap.AddCaller()}
-	if development {
+	if opt.Development {
 		options = append(options, zap.Development())
 	}
 
@@ -87,9 +92,14 @@ func initLogger(r otelfields.Resource, development bool, sinks []zapcore.Core) *
 	// Add a forceSyncer on the core to ensure Sync is executed on the underlying core when Fatal is called, since
 	// after Fatal os.Exit is called per default configuration
 	options = append(options, zap.WithFatalHook(&forceSyncer{core}))
+
+	if opt.StackTraceLevel != zapcore.Level(0) {
+		options = append(options, zap.AddStacktrace(opt.StackTraceLevel))
+	}
+
 	logger := zap.New(core, options...)
 
-	if development {
+	if opt.Development {
 		return logger
 	}