Description
Event attachments added via scope.AddAttachment() are silently dropped when the new telemetry processor is enabled (the default since v0.46.0). The event itself is delivered successfully, but its attachments are missing from the Sentry envelope.
Root Cause
There are two code paths for sending events:
Old path (internalAsyncTransportAdapter.SendEvent in transport.go:935-959) correctly iterates event.Attachments and adds each as a separate envelope item:
for _, attachment := range event.Attachments {
attachmentItem := protocol.NewAttachmentItem(attachment.Filename, attachment.ContentType, attachment.Payload)
envelope.AddItem(attachmentItem)
}New path (Scheduler.sendItem in internal/telemetry/scheduler.go:287-309) only calls item.ToEnvelopeItem() and adds that single item. It never processes event.Attachments:
func (s *Scheduler) sendItem(item protocol.EnvelopeItemConvertible) {
// ...
envelope := protocol.NewEnvelope(header)
envItem, err := item.ToEnvelopeItem()
// ...
envelope.AddItem(envItem)
// No iteration over event.Attachments here
s.transport.SendEnvelope(envelope)
}Event.ToEnvelopeItem() (interfaces.go:462-483) serializes the event JSON body into a single envelope item but does not include attachments (attachments must be separate envelope items per the Sentry protocol).
When DisableTelemetryBuffer is false (the default) and no custom Transport is set, setupTelemetryProcessor() runs and all events flow through the new path, dropping attachments.
Reproduction
sentry.Init(sentry.ClientOptions{
Dsn: "...",
// DisableTelemetryBuffer defaults to false, enabling the telemetry processor
})
event := sentry.NewEvent()
event.Message = "test with attachment"
event.Level = sentry.LevelInfo
sentry.WithScope(func(scope *sentry.Scope) {
scope.AddAttachment(&sentry.Attachment{
Filename: "test.txt",
ContentType: "text/plain",
Payload: []byte("hello world"),
})
sentry.CaptureEvent(event)
})
sentry.Flush(5 * time.Second)
// Event arrives in Sentry, but the attachment is missingWorkaround
Set DisableTelemetryBuffer: true in ClientOptions to force the old transport path:
sentry.Init(sentry.ClientOptions{
Dsn: "...",
DisableTelemetryBuffer: true, // forces old path that handles attachments
})Suggested Fix
In Scheduler.sendItem(), after adding the event envelope item, check if the item has attachments and add them as separate envelope items. Something like:
func (s *Scheduler) sendItem(item protocol.EnvelopeItemConvertible) {
// ... existing code ...
envelope.AddItem(envItem)
// Add attachments if the item supports them
if attachable, ok := item.(interface{ GetAttachments() []*Attachment }); ok {
for _, att := range attachable.GetAttachments() {
envelope.AddItem(protocol.NewAttachmentItem(att.Filename, att.ContentType, att.Payload))
}
}
s.transport.SendEnvelope(envelope)
}Environment
- sentry-go v0.46.0 and v0.46.1 (both affected)
- Go 1.26.2
- Linux amd64
Description
Event attachments added via
scope.AddAttachment()are silently dropped when the new telemetry processor is enabled (the default since v0.46.0). The event itself is delivered successfully, but its attachments are missing from the Sentry envelope.Root Cause
There are two code paths for sending events:
Old path (
internalAsyncTransportAdapter.SendEventintransport.go:935-959) correctly iteratesevent.Attachmentsand adds each as a separate envelope item:New path (
Scheduler.sendItemininternal/telemetry/scheduler.go:287-309) only callsitem.ToEnvelopeItem()and adds that single item. It never processesevent.Attachments:Event.ToEnvelopeItem()(interfaces.go:462-483) serializes the event JSON body into a single envelope item but does not include attachments (attachments must be separate envelope items per the Sentry protocol).When
DisableTelemetryBufferis false (the default) and no customTransportis set,setupTelemetryProcessor()runs and all events flow through the new path, dropping attachments.Reproduction
Workaround
Set
DisableTelemetryBuffer: trueinClientOptionsto force the old transport path:Suggested Fix
In
Scheduler.sendItem(), after adding the event envelope item, check if the item has attachments and add them as separate envelope items. Something like:Environment