mirror of
https://github.com/nais/wonderwall.git
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84 lines
2.5 KiB
Go
84 lines
2.5 KiB
Go
// This code was originally written by Rene Zbinden and modified by Vladimir Konovalov.
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// Copied from https://github.com/766b/chi-prometheus and further adapted.
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package middleware
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import (
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"net/http"
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"strconv"
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"time"
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chi_middleware "github.com/go-chi/chi/v5/middleware"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/nais/wonderwall/pkg/metrics"
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)
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var (
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defaultBuckets = []float64{.001, .01, .05, .1, .5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5}
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)
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const (
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serviceName = "wonderwall"
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reqsName = "requests_total"
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latencyName = "request_duration_seconds"
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)
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// PrometheusMiddleware is a handler that exposes prometheus metrics for the number of requests,
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// the latency and the response size, partitioned by status code, method and HTTP path.
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type PrometheusMiddleware struct {
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reqs *prometheus.CounterVec
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latency *prometheus.HistogramVec
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}
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// Prometheus returns a new PrometheusMiddleware handler.
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func Prometheus(provider string, buckets ...float64) *PrometheusMiddleware {
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var m PrometheusMiddleware
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m.reqs = prometheus.NewCounterVec(
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prometheus.CounterOpts{
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Name: reqsName,
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Help: "How many HTTP requests processed, partitioned by status code, method and HTTP path.",
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ConstLabels: prometheus.Labels{"service": serviceName, metrics.LabelProvider: provider},
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},
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[]string{"code", "method", "path", "host"},
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)
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if len(buckets) == 0 {
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buckets = defaultBuckets
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}
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m.latency = prometheus.NewHistogramVec(prometheus.HistogramOpts{
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Name: latencyName,
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Help: "How long it took to process the request, partitioned by status code, method and HTTP path.",
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ConstLabels: prometheus.Labels{"service": serviceName, metrics.LabelProvider: provider},
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Buckets: buckets,
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},
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[]string{"code", "method", "path", "host"},
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)
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prometheus.Register(m.reqs)
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prometheus.Register(m.latency)
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return &m
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}
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func (m *PrometheusMiddleware) Initialize(path, method string, code int) {
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m.reqs.WithLabelValues(
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strconv.Itoa(code),
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method,
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path,
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)
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}
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func (m *PrometheusMiddleware) Handler(next http.Handler) http.Handler {
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fn := func(w http.ResponseWriter, r *http.Request) {
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start := time.Now()
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ww := chi_middleware.NewWrapResponseWriter(w, r.ProtoMajor)
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next.ServeHTTP(ww, r)
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statusCode := strconv.Itoa(ww.Status())
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duration := time.Since(start)
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m.reqs.WithLabelValues(statusCode, r.Method, r.URL.Path, r.Host).Inc()
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m.latency.WithLabelValues(statusCode, r.Method, r.URL.Path, r.Host).Observe(duration.Seconds())
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}
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return http.HandlerFunc(fn)
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}
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