micro--go-micro
Asim Aslam
550033dcce
* perf: convert generated PNGs to optimized JPEGs (12MB -> 1.5MB) The landing and docs loaded 18 AI-generated PNGs at 0.5-1MB each. They're 1200x800 RGB illustrations with no transparency, so they recompress ~8x as progressive JPEG (quality 82) with no visible loss. Convert all, update every reference (.png -> .jpg), and drop the originals (including the unused hero.png). Generated images: 12.3MB -> 1.5MB. * fix(registry/etcd): re-register when a lease silently expires (#2956) The keepalive rework (long-lived KeepAlive instead of KeepAliveOnce) moved lease renewal entirely onto the keepalive goroutine; the 30s periodic Register now skips on the 'unchanged' check. The goroutine only reacted to the keepalive channel closing, so a lease that expired server-side without a prompt channel close (e.g. a partition that outlasted the 90s TTL) left the node de-registered from etcd while the cache still believed it was registered — and nothing re-registered it. That is the hidden-failure mode reported in #2956. React to a non-positive TTL keepalive response the same as a channel close: drop the cached lease/hash so the next Register performs a full re-registration. Extract the loop into keepAliveLoop and unit-test the TTL-expired, channel-closed, and healthy paths (no etcd required). --------- Co-authored-by: Claude <noreply@anthropic.com>
96 行
2.7 KiB
Markdown
96 行
2.7 KiB
Markdown
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layout: default
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---
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# Observability
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<img src="/images/generated/observability.jpg" alt="Observability" style="width: 100%; border-radius: 8px; margin: 1rem 0 1.5rem;" />
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Observability in Go Micro spans logs, metrics, and traces. The goal is rapid insight into service behavior with minimal configuration.
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## Core Principles
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1. Structured Logs – Machine-parsable, leveled output
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2. Metrics – Quantitative trends (counters, gauges, histograms)
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3. Traces – Request flows across service boundaries
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4. Correlation – IDs flowing through all three signals
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## Logging
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The default logger can be replaced. Use env vars to adjust level:
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```bash
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MICRO_LOG_LEVEL=debug go run main.go
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```
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Recommended fields:
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- `service` – service name
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- `version` – release identifier
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- `trace_id` – propagated context id
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- `span_id` – current operation id
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## Metrics
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Patterns:
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- Emit counters for request totals
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- Use histograms for latency
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- Track error rates per endpoint
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Example (pseudo-code):
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```go
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// Wrap handler to record metrics
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func MetricsWrapper(fn micro.HandlerFunc) micro.HandlerFunc {
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return func(ctx context.Context, req micro.Request, rsp interface{}) error {
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start := time.Now()
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err := fn(ctx, req, rsp)
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latency := time.Since(start)
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metrics.Inc("requests_total", req.Endpoint(), errorLabel(err))
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metrics.Observe("request_latency_seconds", latency, req.Endpoint())
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return err
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}
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}
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```
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## Tracing
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Distributed tracing links calls across services.
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Propagation strategy:
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- Extract trace context from incoming headers
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- Inject into outgoing RPC calls/broker messages
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- Create spans per handler and client call
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## Local Development Strategy
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Start with only structured logs. Add metrics when operating multiple services. Introduce tracing once debugging multi-hop latency or failures.
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## Roadmap (Planned Enhancements)
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- Native OpenTelemetry exporter helpers
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- Automatic handler/client wrapping for spans
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- Default correlation IDs across broker messages
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## Deployment Recommendations
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| Scale | Suggested Stack |
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|-------|-----------------|
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| Dev | Console logs only |
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| Staging | Logs + basic metrics (Prometheus) |
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| Prod (basic) | Logs + metrics + sampling traces |
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| Prod (complex) | Full tracing + profiling + anomaly detection |
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## Troubleshooting
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| Symptom | Cause | Fix |
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|---------|-------|-----|
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| Missing trace IDs in logs | Context not propagated | Ensure wrappers add IDs |
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| Metrics server empty | Endpoint not scraped | Verify Prometheus config |
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| High cardinality metrics | Dynamic labels | Reduce labeled dimensions |
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## Related
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- [Getting Started](getting-started.html)
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- [Plugins](plugins.html)
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- [Architecture Decisions](architecture/index.md)
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