1 files changed, 71 insertions, 0 deletions
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/example_timer_complex_test.go b/vendor/github.com/prometheus/client_golang/prometheus/example_timer_complex_test.go
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index 000000000..c5e7de5e5
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@@ -0,0 +1,71 @@
+// Copyright 2014 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package prometheus_test
+
+import (
+	"net/http"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	// apiRequestDuration tracks the duration separate for each HTTP status
+	// class (1xx, 2xx, ...). This creates a fair amount of time series on
+	// the Prometheus server. Usually, you would track the duration of
+	// serving HTTP request without partitioning by outcome. Do something
+	// like this only if needed. Also note how only status classes are
+	// tracked, not every single status code. The latter would create an
+	// even larger amount of time series. Request counters partitioned by
+	// status code are usually OK as each counter only creates one time
+	// series. Histograms are way more expensive, so partition with care and
+	// only where you really need separate latency tracking. Partitioning by
+	// status class is only an example. In concrete cases, other partitions
+	// might make more sense.
+	apiRequestDuration = prometheus.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Name:    "api_request_duration_seconds",
+			Help:    "Histogram for the request duration of the public API, partitioned by status class.",
+			Buckets: prometheus.ExponentialBuckets(0.1, 1.5, 5),
+		},
+		[]string{"status_class"},
+	)
+)
+
+func handler(w http.ResponseWriter, r *http.Request) {
+	status := http.StatusOK
+	// The ObserverFunc gets called by the deferred ObserveDuration and
+	// decides which Histogram's Observe method is called.
+	timer := prometheus.NewTimer(prometheus.ObserverFunc(func(v float64) {
+		switch {
+		case status >= 500: // Server error.
+			apiRequestDuration.WithLabelValues("5xx").Observe(v)
+		case status >= 400: // Client error.
+			apiRequestDuration.WithLabelValues("4xx").Observe(v)
+		case status >= 300: // Redirection.
+			apiRequestDuration.WithLabelValues("3xx").Observe(v)
+		case status >= 200: // Success.
+			apiRequestDuration.WithLabelValues("2xx").Observe(v)
+		default: // Informational.
+			apiRequestDuration.WithLabelValues("1xx").Observe(v)
+		}
+	}))
+	defer timer.ObserveDuration()
+
+	// Handle the request. Set status accordingly.
+	// ...
+}
+
+func ExampleTimer_complex() {
+	http.HandleFunc("/api", handler)
+}