47 lines
1.2 KiB
Go
47 lines
1.2 KiB
Go
// Prometheus metrics: counter, histogram, gauge, and /metrics endpoint.
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package main
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import (
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"fmt"
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"log"
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"math/rand/v2"
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"net/http"
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"time"
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"git.codelab.vc/pkg/obsx"
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)
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func main() {
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metrics := obsx.NewMetrics(obsx.MetricsConfig{
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Namespace: "myapp",
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Subsystem: "api",
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})
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requests := metrics.Counter("requests_total", "Total HTTP requests", "method", "status")
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duration := metrics.Histogram("request_duration_seconds", "Request latency", nil, "method")
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inflight := metrics.Gauge("inflight_requests", "Current in-flight requests")
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mux := http.NewServeMux()
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mux.HandleFunc("GET /hello", func(w http.ResponseWriter, r *http.Request) {
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inflight.WithLabelValues().Inc()
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defer inflight.WithLabelValues().Dec()
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start := time.Now()
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// Simulate work.
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time.Sleep(time.Duration(rand.IntN(100)) * time.Millisecond)
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w.WriteHeader(http.StatusOK)
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fmt.Fprintln(w, "hello, world")
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requests.WithLabelValues("GET", "200").Inc()
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duration.WithLabelValues("GET").Observe(time.Since(start).Seconds())
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})
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mux.Handle("GET /metrics", metrics.Handler())
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log.Println("listening on :8080 (try GET /hello, GET /metrics)")
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log.Fatal(http.ListenAndServe(":8080", mux))
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}
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