The IAM server's KeepConnectedToMaster goroutine used context.Background(),
which is non-cancellable, causing the goroutine and its gRPC connections
to leak on server shutdown.
Problem:
go masterClient.KeepConnectedToMaster(context.Background())
- context.Background() never cancels
- KeepConnectedToMaster goroutine runs forever
- gRPC connection to master stays open
- No way to stop cleanly on server shutdown
Result: Resource leaks when IAM server is stopped
Fix:
1. Added shutdownContext and shutdownCancel to IamApiServer struct
2. Created cancellable context in NewIamApiServerWithStore:
shutdownCtx, shutdownCancel := context.WithCancel(context.Background())
3. Pass shutdownCtx to KeepConnectedToMaster:
go masterClient.KeepConnectedToMaster(shutdownCtx)
4. Added Shutdown() method to invoke cancel:
func (iama *IamApiServer) Shutdown() {
if iama.shutdownCancel != nil {
iama.shutdownCancel()
}
}
5. Stored masterClient reference on IamApiServer for future use
Benefits:
- Goroutine stops cleanly when Shutdown() is called
- gRPC connections are closed properly
- No resource leaks on server restart/stop
- Shutdown() is idempotent (safe to call multiple times)
Usage (for future graceful shutdown):
iamServer, _ := iamapi.NewIamApiServer(...)
defer iamServer.Shutdown()
// or in signal handler:
sigChan := make(chan os.Signal, 1)
signal.Notify(sigChan, syscall.SIGTERM, syscall.SIGINT)
go func() {
<-sigChan
iamServer.Shutdown()
os.Exit(0)
}()
Note: Current command implementations (weed/command/iam.go) don't have
shutdown paths yet, but this makes IAM server ready for proper lifecycle
management when that infrastructure is added.
The IAM server creates and uses a MasterClient but never started
KeepConnectedToMaster, which could cause blocking if IAM config files
have chunks requiring volume lookups.
Problem flow:
NewIamApiServerWithStore()
→ creates masterClient
→ ❌ NEVER starts KeepConnectedToMaster
GetS3ApiConfigurationFromFiler()
→ filer.ReadEntry(iama.masterClient, ...)
→ StreamContent(masterClient, ...) if file has chunks
→ masterClient.GetLookupFileIdFunction()
→ GetMaster(ctx) ← BLOCKS indefinitely waiting for connection!
While IAM config files (identity & policies) are typically small and
stored inline without chunks, the code path exists and would block
if the files ever had chunks.
Fix:
Start KeepConnectedToMaster in background goroutine right after
creating masterClient, following the documented pattern:
mc := wdclient.NewMasterClient(...)
go mc.KeepConnectedToMaster(ctx)
This ensures masterClient is usable if ReadEntry ever needs to
stream chunked content from volume servers.
Note: This bug was dormant because IAM config files are small (<256 bytes)
and SeaweedFS stores small files inline in Entry.Content, not as chunks.
The bug would only manifest if:
- IAM config grew > 256 bytes (inline threshold)
- Config was stored as chunks on volume servers
- ReadEntry called StreamContent
- GetMaster blocked indefinitely
Now all 9 production MasterClient instances correctly follow the pattern.
chrislu
Chris Lu
Konstantin Lebedev
Nico D'Cotta
Ryan Russell
guosj
Konstantin Lebedev