71 lines
2.3 KiB
Markdown
71 lines
2.3 KiB
Markdown
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# telemetry
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OTel SDK bootstrap — wires up TracerProvider, MeterProvider, and LoggerProvider with OTLP gRPC exporters pointed at Grafana Alloy (→ Tempo / Mimir / Loki).
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**Tier 5 — import only from application `main` packages. Never import from framework libraries.**
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## Why Tier 5
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Micro-libs use only the OTel API (`go.opentelemetry.io/otel`) which ships a zero-overhead no-op default. This module activates the real SDK and sets the three OTel globals, so all micro-libs using the global API auto-instrument without knowing about this module.
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## Installation
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```
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require code.nochebuena.dev/go/telemetry v0.1.0
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```
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## Usage
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```go
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func main() {
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ctx := context.Background()
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// Bootstrap telemetry before any other component.
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shutdown, err := telemetry.New(ctx, telemetry.Config{
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ServiceName: "order-service",
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OTLPEndpoint: "alloy:4317",
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OTLPInsecure: true, // dev only
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})
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if err != nil {
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log.Fatalf("telemetry: %v", err)
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}
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defer shutdown(ctx)
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// Start the rest of the application…
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}
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```
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## Config
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| Field | Env var | Required | Default | Description |
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|---|---|---|---|---|
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| `ServiceName` | `OTEL_SERVICE_NAME` | ✓ | — | Service name in traces/metrics/logs |
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| `ServiceVersion` | `OTEL_SERVICE_VERSION` | | `unknown` | Deployed version |
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| `Environment` | `OTEL_ENVIRONMENT` | | `development` | Deployment environment |
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| `OTLPEndpoint` | `OTEL_EXPORTER_OTLP_ENDPOINT` | ✓ | — | OTLP gRPC address (e.g. `alloy:4317`) |
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| `OTLPInsecure` | `OTEL_EXPORTER_OTLP_INSECURE` | | `false` | Disable TLS (dev only) |
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## What `New` sets up
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| Signal | SDK | Exporter | Backend |
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|---|---|---|---|
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| Traces | `sdktrace.TracerProvider` | OTLP gRPC | Grafana Alloy → Tempo |
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| Metrics | `sdkmetric.MeterProvider` | OTLP gRPC | Grafana Alloy → Mimir |
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| Logs | `sdklog.LoggerProvider` | OTLP gRPC | Grafana Alloy → Loki |
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Also sets `otel.SetTextMapPropagator` with W3C TraceContext + Baggage.
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## Shutdown
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The returned `func(context.Context) error` flushes all pending telemetry and shuts down the three providers. Always call it before process exit.
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```go
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defer func() {
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shutCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
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defer cancel()
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if err := shutdown(shutCtx); err != nil {
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log.Printf("telemetry shutdown: %v", err)
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}
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}()
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```
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