mirror of https://github.com/vernonkeenan/lib
68 lines
1.9 KiB
Go
68 lines
1.9 KiB
Go
package app
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import (
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"fmt"
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"net/http"
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"time"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/rs/cors"
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)
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var (
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namespace = "collage"
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counter = prometheus.NewCounterVec(prometheus.CounterOpts{
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Namespace: namespace,
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Name: "endpoint_request_count",
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Help: "collage request count.",
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}, []string{"app", "name", "method", "state"})
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histogram = prometheus.NewHistogramVec(prometheus.HistogramOpts{
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Namespace: namespace,
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Name: "endpoint_duration_seconds",
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Help: "Time taken to execute endpoint.",
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}, []string{"app", "name", "method", "status"})
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)
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type metricResponseWriter struct {
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http.ResponseWriter
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statusCode int
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}
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func newMetricResponseWriter(w http.ResponseWriter) *metricResponseWriter {
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return &metricResponseWriter{w, http.StatusOK}
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}
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func (lrw *metricResponseWriter) WriteHeader(code int) {
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lrw.statusCode = code
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lrw.ResponseWriter.WriteHeader(code)
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}
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// SetupPrometheusHandler enable CORS, handler metrics
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func SetupPrometheusHandler(handler http.Handler, app string) http.Handler {
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sugar.Debug("app.SetupPrometheusHandler: 📥")
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handleCORS := cors.AllowAll().Handler
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h := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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start := time.Now()
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lrw := newMetricResponseWriter(w)
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handler.ServeHTTP(lrw, r)
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statusCode := lrw.statusCode
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duration := time.Since(start)
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histogram.WithLabelValues(app, r.URL.String(), r.Method, fmt.Sprintf("%d", statusCode)).Observe(duration.Seconds())
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counter.WithLabelValues(app, r.URL.String(), r.Method, fmt.Sprintf("%d", statusCode)).Inc()
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})
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err := prometheus.Register(histogram)
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if err != nil {
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sugar.Errorf("app.SetupPrometheusHandler: 💣 ⛔ %s", err.Error())
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return nil
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}
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err = prometheus.Register(counter)
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if err != nil {
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sugar.Errorf("app.SetupPrometheusHandler: 💣 ⛔ %s", err.Error())
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return nil
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}
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sugar.Info("app.SetupPrometheusHandler: 👍 📤")
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return handleCORS(h)
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}
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