fix(logger): prevent mutex crash in bufferingExporter

Remove sync.Once reset that caused "unlock of unlocked mutex" panic.
Redesign initialization to use only checkReadiness goroutine for
retry attempts, eliminating race condition while preserving retry
functionality for TLS/tracing setup delays.
This commit is contained in:
Ask Bjørn Hansen 2025-08-02 22:55:57 -07:00
parent 0b9769dc39
commit a774f92bf7

View File

@ -23,9 +23,8 @@ type bufferingExporter struct {
// Real exporter (created when tracing is configured) // Real exporter (created when tracing is configured)
exporter otellog.Exporter exporter otellog.Exporter
// Thread-safe initialization // Thread-safe initialization state (managed only by checkReadiness)
initOnce sync.Once initErr error
initErr error
// Background checker // Background checker
stopChecker chan struct{} stopChecker chan struct{}
@ -48,20 +47,13 @@ func newBufferingExporter() *bufferingExporter {
// Export implements otellog.Exporter // Export implements otellog.Exporter
func (e *bufferingExporter) Export(ctx context.Context, records []otellog.Record) error { func (e *bufferingExporter) Export(ctx context.Context, records []otellog.Record) error {
// Try initialization once // Check if exporter is ready (initialization handled by checkReadiness goroutine)
e.initOnce.Do(func() { e.mu.RLock()
e.initErr = e.initialize() exporter := e.exporter
}) e.mu.RUnlock()
// If initialization succeeded, use the exporter if exporter != nil {
if e.initErr == nil { return exporter.Export(ctx, records)
e.mu.RLock()
exporter := e.exporter
e.mu.RUnlock()
if exporter != nil {
return exporter.Export(ctx, records)
}
} }
// Not ready yet, buffer the records // Not ready yet, buffer the records
@ -117,24 +109,31 @@ func (e *bufferingExporter) bufferRecords(records []otellog.Record) error {
return nil return nil
} }
// checkReadiness periodically checks if tracing is configured // checkReadiness periodically attempts initialization until successful
func (e *bufferingExporter) checkReadiness() { func (e *bufferingExporter) checkReadiness() {
defer close(e.checkerDone) defer close(e.checkerDone)
ticker := time.NewTicker(1 * time.Second) // Reduced frequency since OTLP handles retries ticker := time.NewTicker(1 * time.Second)
defer ticker.Stop() defer ticker.Stop()
for { for {
select { select {
case <-ticker.C: case <-ticker.C:
// If initialization failed, reset sync.Once to allow retry // Check if we already have a working exporter
// The OTLP exporter will handle its own retry logic e.mu.RLock()
if e.initErr != nil { hasExporter := e.exporter != nil
e.initOnce = sync.Once{} e.mu.RUnlock()
} else if e.exporter != nil {
if hasExporter {
return // Exporter ready, checker no longer needed return // Exporter ready, checker no longer needed
} }
// Try to initialize
err := e.initialize()
e.mu.Lock()
e.initErr = err
e.mu.Unlock()
case <-e.stopChecker: case <-e.stopChecker:
return return
} }
@ -180,14 +179,21 @@ func (e *bufferingExporter) Shutdown(ctx context.Context) error {
// Stop the readiness checker from continuing // Stop the readiness checker from continuing
close(e.stopChecker) close(e.stopChecker)
// Give one final chance for TLS/tracing to become ready before fully shutting down
e.initOnce.Do(func() {
e.initErr = e.initialize()
})
// Wait for readiness checker goroutine to complete // Wait for readiness checker goroutine to complete
<-e.checkerDone <-e.checkerDone
// Give one final chance for TLS/tracing to become ready for buffer flushing
e.mu.RLock()
hasExporter := e.exporter != nil
e.mu.RUnlock()
if !hasExporter {
err := e.initialize()
e.mu.Lock()
e.initErr = err
e.mu.Unlock()
}
e.mu.Lock() e.mu.Lock()
defer e.mu.Unlock() defer e.mu.Unlock()