client_golang/examples/random/main.go

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// Copyright (c) 2013, Prometheus Team
// All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// A simple example of how to use this instrumentation framework in the context
// of having something that emits values into its collectors.
//
// The emitted values correspond to uniform, normal, and exponential
// distributions.
package main
import (
"flag"
"github.com/prometheus/client_golang/prometheus"
"math/rand"
"net/http"
"time"
)
var (
barDomain = flag.Float64("random.fooDomain", 200, "The domain for the random parameter foo.")
barMean = flag.Float64("random.barDomain", 10, "The domain for the random parameter bar.")
fooDomain = flag.Float64("random.barMean", 100, "The mean for the random parameter bar.")
// Create a histogram to track fictitious interservice RPC latency for three
// distinct services.
rpcLatency = prometheus.NewHistogram(&prometheus.HistogramSpecification{
// Four distinct histogram buckets for values:
// - equally-sized,
// - 0 to 50, 50 to 100, 100 to 150, and 150 to 200.
Starts: prometheus.EquallySizedBucketsFor(0, 200, 4),
// Create histogram buckets using an accumulating bucket, a bucket that
// holds sample values subject to an eviction policy:
// - 50 elements are allowed per bucket.
// - Once 50 have been reached, the bucket empties 10 elements, averages the
// evicted elements, and re-appends that back to the bucket.
BucketBuilder: prometheus.AccumulatingBucketBuilder(prometheus.EvictAndReplaceWith(10, prometheus.AverageReducer), 50),
// The histogram reports percentiles 1, 5, 50, 90, and 99.
ReportablePercentiles: []float64{0.01, 0.05, 0.5, 0.90, 0.99},
})
rpcCalls = prometheus.NewCounter()
// If for whatever reason you are resistant to the idea of having a static
// registry for metrics, which is a really bad idea when using Prometheus-
// enabled library code, you can create your own.
customRegistry = prometheus.NewRegistry()
)
func main() {
flag.Parse()
go func() {
for {
rpcLatency.Add(map[string]string{"service": "foo"}, rand.Float64()**fooDomain)
rpcCalls.Increment(map[string]string{"service": "foo"})
rpcLatency.Add(map[string]string{"service": "bar"}, (rand.NormFloat64()**barDomain)+*barMean)
rpcCalls.Increment(map[string]string{"service": "bar"})
rpcLatency.Add(map[string]string{"service": "zed"}, rand.ExpFloat64())
rpcCalls.Increment(map[string]string{"service": "zed"})
time.Sleep(100 * time.Millisecond)
}
}()
http.Handle(prometheus.ExpositionResource, customRegistry.Handler())
http.ListenAndServe(*listeningAddress, nil)
}
func init() {
customRegistry.Register("rpc_latency_microseconds", "RPC latency.", prometheus.NilLabels, rpcLatency)
customRegistry.Register("rpc_calls_total", "RPC calls.", prometheus.NilLabels, rpcCalls)
}
var (
listeningAddress = flag.String("listeningAddress", ":8080", "The address to listen to requests on.")
)