| // Copyright 2015 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. |
| |
| // A simple example exposing fictional RPC latencies with different types of |
| // random distributions (uniform, normal, and exponential) as Prometheus |
| // metrics. |
| package main |
| |
| import ( |
| "flag" |
| "log" |
| "math" |
| "math/rand" |
| "net/http" |
| "time" |
| |
| "github.com/prometheus/client_golang/prometheus" |
| "github.com/prometheus/client_golang/prometheus/promhttp" |
| ) |
| |
| var ( |
| addr = flag.String("listen-address", ":8080", "The address to listen on for HTTP requests.") |
| uniformDomain = flag.Float64("uniform.domain", 0.0002, "The domain for the uniform distribution.") |
| normDomain = flag.Float64("normal.domain", 0.0002, "The domain for the normal distribution.") |
| normMean = flag.Float64("normal.mean", 0.00001, "The mean for the normal distribution.") |
| oscillationPeriod = flag.Duration("oscillation-period", 10*time.Minute, "The duration of the rate oscillation period.") |
| ) |
| |
| var ( |
| // Create a summary to track fictional interservice RPC latencies for three |
| // distinct services with different latency distributions. These services are |
| // differentiated via a "service" label. |
| rpcDurations = prometheus.NewSummaryVec( |
| prometheus.SummaryOpts{ |
| Name: "rpc_durations_seconds", |
| Help: "RPC latency distributions.", |
| Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001}, |
| }, |
| []string{"service"}, |
| ) |
| // The same as above, but now as a histogram, and only for the normal |
| // distribution. The buckets are targeted to the parameters of the |
| // normal distribution, with 20 buckets centered on the mean, each |
| // half-sigma wide. |
| rpcDurationsHistogram = prometheus.NewHistogram(prometheus.HistogramOpts{ |
| Name: "rpc_durations_histogram_seconds", |
| Help: "RPC latency distributions.", |
| Buckets: prometheus.LinearBuckets(*normMean-5**normDomain, .5**normDomain, 20), |
| }) |
| ) |
| |
| func init() { |
| // Register the summary and the histogram with Prometheus's default registry. |
| prometheus.MustRegister(rpcDurations) |
| prometheus.MustRegister(rpcDurationsHistogram) |
| } |
| |
| func main() { |
| flag.Parse() |
| |
| start := time.Now() |
| |
| oscillationFactor := func() float64 { |
| return 2 + math.Sin(math.Sin(2*math.Pi*float64(time.Since(start))/float64(*oscillationPeriod))) |
| } |
| |
| // Periodically record some sample latencies for the three services. |
| go func() { |
| for { |
| v := rand.Float64() * *uniformDomain |
| rpcDurations.WithLabelValues("uniform").Observe(v) |
| time.Sleep(time.Duration(100*oscillationFactor()) * time.Millisecond) |
| } |
| }() |
| |
| go func() { |
| for { |
| v := (rand.NormFloat64() * *normDomain) + *normMean |
| rpcDurations.WithLabelValues("normal").Observe(v) |
| rpcDurationsHistogram.Observe(v) |
| time.Sleep(time.Duration(75*oscillationFactor()) * time.Millisecond) |
| } |
| }() |
| |
| go func() { |
| for { |
| v := rand.ExpFloat64() / 1e6 |
| rpcDurations.WithLabelValues("exponential").Observe(v) |
| time.Sleep(time.Duration(50*oscillationFactor()) * time.Millisecond) |
| } |
| }() |
| |
| // Expose the registered metrics via HTTP. |
| http.Handle("/metrics", promhttp.Handler()) |
| log.Fatal(http.ListenAndServe(*addr, nil)) |
| } |