fix: fix zap.Any logging issues causing unsupported value type errors

[agrawaliti]

Problem

The zap.Any logger was being used with complex objects in the latency metrics module, resulting in uninformative "unsupported value type" error messages that made debugging difficult:

ts=2025-06-12T14:49:33.339Z level=debug caller=metrics/latency.go:126 msg="Evicted item" item= itemError="unsupported value type"
ts=2025-06-12T14:43:38.295Z level=debug caller=metrics/latency.go:129 msg="Incremented no response metric" metric= metricError="unsupported value type"

Solution

Replaced zap.Any calls with appropriate structured logging using specific zap field types:

Before (problematic):

lm.l.Debug("Evicted item", zap.Any("item", item))
lm.l.Debug("Incremented no response metric", zap.Any("metric", lm.noResponseMetric))
lm.l.Debug("Add apiserver ips", zap.Any("ips", apiServerIPs))

After (fixed):

k := item.Key()
v := item.Value()
lm.l.Debug("Evicted item", 
    zap.String("srcIP", k.srcIP),
    zap.String("dstIP", k.dstIP),
    zap.Uint32("srcPort", k.srcP),
    zap.Uint32("dstPort", k.dstP),
    zap.Uint64("id", k.id),
    zap.Int32("timestamp", v.t))

lm.l.Debug("Incremented no response metric", zap.String("metric", "adv_node_apiserver_no_response"))

ipStrings := make([]string, len(apiServerIPs))
for i, ip := range apiServerIPs {
    ipStrings[i] = ip.String()
}
lm.l.Debug("Add apiserver ips", zap.Strings("ips", ipStrings))

Logs before and after:

ts=2025-06-12T14:49:33.339Z level=debug caller=metrics/latency.go:126 msg="Evicted item" item= itemError="unsupported value type"
ts=2025-06-12T14:43:38.295Z level=debug caller=metrics/latency.go:129 msg="Incremented no response metric" metric= metricError="unsupported value type"

ts=2025-07-23T16:20:50.047Z level=debug caller=metrics/latency.go:128 msg="Evicted item" srcIP=10.224.0.4 dstIP=20.13.226.96 srcPort=56272 dstPort=443 id=614403966 timestamp=543825424
ts=2025-07-23T16:20:50.047Z level=debug caller=metrics/latency.go:137 msg="Incremented no response metric" metric=adv_node_apiserver_no_response

Benefits

• Informative logging: Debug messages now show actual values instead of "unsupported value type"
• Better debugging: Network connection details (IPs, ports, timestamps) are clearly visible
• Structured data: Proper field names make log parsing and analysis easier
• No breaking changes: Only affects debug log output format

Testing

• All existing tests pass (23/23)
• No "unsupported value type" errors from latency.go in test output
• Verified structured logging produces readable output with meaningful field names

Fixes #1680.

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[agrawaliti]

Signed PR of: #1704

[ritwikranjan]

lgtm other than the hardcoded metric name.

[ritwikranjan]

lgtm

[agrawaliti]

Verified logs with the final changes

ts=2025-07-30T12:50:25.048Z level=debug caller=metrics/latency.go:128 msg="Evicted item" srcIP=10.224.0.4 dstIP=20.116.148.139 srcPort=56124 dstPort=443 id=559864698 timestamp=425380656
ts=2025-07-30T12:50:25.048Z level=debug caller=metrics/latency.go:137 msg="Incremented no response metric" metric=adv_node_apiserver_no_response
ts=2025-07-30T12:50:25.082Z level=debug caller=packetparser/packetparser_linux.go:564 msg="Received record" cpu=3 lost_samples=0 bytes_remaining=136 worker_id=0
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