Address CodeRabbit review #3512078995:
1. **Critical: Fix unsynchronized read in error message**
- Line 584 read len(fc.filerAddresses) without lock
- Race with refreshFilerList appending to slice
- Fixed: Take RLock to read length safely
- Prevents race detector warnings
2. **Important: Make Close() idempotent**
- Closing already-closed channel panics
- Can happen with layered cleanup in shutdown paths
- Fixed: Use sync.Once to ensure single close
- Safe to call Close() multiple times now
3. **Nitpick: Add warning for empty filer address**
- getFilerAddress() can return empty string
- Helps diagnose unexpected state
- Added: Warning log when no filers available
4. **Nitpick: Guard deprecated index-based helpers**
- shouldSkipUnhealthyFiler, recordFilerSuccess/Failure
- Accessed filerHealth without lock (races with discovery)
- Fixed: Take RLock and check bounds before array access
- Prevents index out of bounds and races
Changes:
- filer_client.go:
- Add closeDiscoveryOnce sync.Once field
- Use Do() in Close() for idempotent channel close
- Add RLock guards to deprecated index-based helpers
- Add bounds checking to prevent panics
- Synchronized read of filerAddresses length in error
- s3api_server.go:
- Add warning log when getFilerAddress returns empty
Benefits:
- No race conditions (passes race detector)
- No panic on double-close
- Better error diagnostics
- Safe with discovery enabled
- Production-hardened shutdown logic
see https://blog.aqwari.net/xml-schema-go/
1. go get aqwari.net/xml/cmd/xsdgen
2. Add EncodingType element for ListBucketResult in AmazonS3.xsd
3. xsdgen -o s3api_xsd_generated.go -pkg s3api AmazonS3.xsd
4. Remove empty Grantee struct in s3api_xsd_generated.go
5. Remove xmlns: sed s'/http:\/\/s3.amazonaws.com\/doc\/2006-03-01\/\ //' s3api_xsd_generated.go