b840047e19
ci: add GitHub Pages deployment workflow for docs site Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
60 lines
1.7 KiB
Go
60 lines
1.7 KiB
Go
package observability
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import (
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"context"
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"log/slog"
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"net/http"
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"time"
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"github.com/prometheus/client_golang/prometheus/promhttp"
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)
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// StartServer starts an HTTP server for Prometheus metrics and health checks.
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//
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// The server exposes:
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// - GET /metrics — Prometheus metrics endpoint
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// - GET /health — Liveness probe (returns 200 with {"status":"ok"})
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//
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// The server shuts down gracefully when ctx is cancelled. It runs in a
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// goroutine and does not block the caller.
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func StartServer(ctx context.Context, addr string) *http.Server {
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mux := http.NewServeMux()
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mux.Handle("/metrics", promhttp.Handler())
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mux.HandleFunc("/health", healthHandler)
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srv := &http.Server{
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Addr: addr,
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Handler: mux,
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ReadHeaderTimeout: 5 * time.Second,
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}
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// Start serving in a goroutine.
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go func() {
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slog.Info("observability server starting", "addr", addr)
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if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
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slog.Error("observability server error", "error", err)
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}
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}()
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// Graceful shutdown when context is cancelled.
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go func() {
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<-ctx.Done()
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slog.Info("observability server shutting down")
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shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
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defer cancel()
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if err := srv.Shutdown(shutdownCtx); err != nil {
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slog.Error("observability server shutdown error", "error", err)
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}
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slog.Info("observability server stopped")
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}()
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return srv
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}
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// healthHandler returns a simple liveness response.
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func healthHandler(w http.ResponseWriter, _ *http.Request) {
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w.Header().Set("Content-Type", "application/json")
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w.WriteHeader(http.StatusOK)
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_, _ = w.Write([]byte(`{"status":"ok"}`))
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}
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