Feature Request: Migrate from klog to Zap for True Structured Logging Support

[james-rem]

Feature Request: Migrate from klog to Zap for True Structured Logging Support

Summary

Replace the current klog-based logging implementation in csi-driver-smb with Uber's Zap logging library to enable proper structured logging with JSON output and improved observability.

Problem Statement

The current logging implementation in csi-driver-smb uses klog v2, which has significant limitations for structured logging:

1. No Native JSON Output: klog's "structured" logging (InfoS, ErrorS) outputs key=value format, not JSON
2. Limited Field Types: klog doesn't handle complex field types well (nested objects, arrays)
3. Poor Integration with Modern Observability: Most log aggregation systems (ELK, Grafana, Datadog) expect JSON logs
4. Difficult Debugging: Key=value format is harder to parse and search compared to proper JSON
5. No Context Propagation: Limited ability to carry request context through log messages

Current State Example

klog.InfoS("Processing mount request",
  "volumeId", req.VolumeId,
  "targetPath", req.TargetPath,
  "mountOptions", req.VolumeCapability.GetMount().MountFlags)

Output:

I0409 12:34:56.123456 1234 nodeserver.go:45] "Processing mount request" volumeId="pvc-123" targetPath="/var/lib/kubelet/pods/..." mountOptions=[rw,file_mode=0777]

This format is:

• Not parseable as JSON
• Difficult to query in log aggregation systems
• Missing timestamps in structured format
• Lacks correlation IDs for tracing

Proposed Solution

Migrate to Uber Zap for structured logging with the following benefits:

1. True JSON Output

logger.Info("Processing mount request",
  zap.String("volumeId", req.VolumeId),
  zap.String("targetPath", req.TargetPath),
  zap.Strings("mountOptions", req.VolumeCapability.GetMount().MountFlags),
  zap.String("requestId", requestId))

Output:

{
"level": "info",
"ts": 1712345678.123456,
"caller": "smb/nodeserver.go:45",
"msg": "Processing mount request",
"volumeId": "pvc-123",
"targetPath": "/var/lib/kubelet/pods/...",
"mountOptions": ["rw", "file_mode=0777"],
"requestId": "req-abc123"
}