mox!

metrics/http.go

@@ -0,0 +1,61 @@
+// Package metrics has prometheus metric variables/functions.
+package metrics
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+
+	"github.com/mjl-/mox/mlog"
+)
+
+var xlog = mlog.New("metrics")
+
+var (
+	metricHTTPClient = promauto.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Name:    "mox_httpclient_request_duration_seconds",
+			Help:    "HTTP requests lookups.",
+			Buckets: []float64{0.01, 0.05, 0.100, 0.5, 1, 5, 10, 20, 30},
+		},
+		[]string{
+			"pkg",
+			"method",
+			"code",
+			"result",
+		},
+	)
+)
+
+// HTTPClientObserve tracks the result of an HTTP transaction in a metric, and
+// logs the result.
+func HTTPClientObserve(ctx context.Context, pkg, method string, statusCode int, err error, start time.Time) {
+	log := xlog.WithContext(ctx)
+	var result string
+	switch {
+	case err == nil:
+		switch statusCode / 100 {
+		case 2:
+			result = "ok"
+		case 4:
+			result = "usererror"
+		case 5:
+			result = "servererror"
+		default:
+			result = "other"
+		}
+	case errors.Is(err, os.ErrDeadlineExceeded) || errors.Is(err, context.DeadlineExceeded):
+		result = "timeout"
+	case errors.Is(err, context.Canceled):
+		result = "canceled"
+	default:
+		result = "error"
+	}
+	metricHTTPClient.WithLabelValues(pkg, method, result, fmt.Sprintf("%d", statusCode)).Observe(float64(time.Since(start)) / float64(time.Second))
+	log.Debugx("httpclient result", err, mlog.Field("pkg", pkg), mlog.Field("method", method), mlog.Field("code", statusCode), mlog.Field("duration", time.Since(start)))
+}