Update FilerEtcStore to use a function that returns the current active
filer instead of a fixed address, enabling high availability.
Changes:
- Add SetFilerAddressFunc() method to FilerEtcStore
- Store uses filerAddressFunc instead of fixed filerGrpcAddress
- withFilerClient() calls the function to get current active filer
- Keep SetFilerClient() for backward compatibility (marked deprecated)
- Update S3ApiServer to pass FilerClient.GetCurrentFiler to store
Benefits:
- Credential store now uses currently active/healthy filer
- Automatic failover when filer becomes unavailable
- True HA for credential operations
- Backward compatible with old SetFilerClient interface
This addresses the credential store limitation - no longer pinned to
first filer, uses FilerClient's tracked current active filer.
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