89 lines
3.1 KiB
Go
89 lines
3.1 KiB
Go
// Copyright (c) 2012, Matt T. Proud
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// All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// A simple example of how to use this instrumentation framework in the context
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// of having something that emits values into its collectors.
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//
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// The emitted values correspond to uniform, normal, and exponential
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// distributions.
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package main
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import (
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"flag"
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"github.com/prometheus/client_golang"
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"github.com/prometheus/client_golang/maths"
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"github.com/prometheus/client_golang/metrics"
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"math/rand"
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"net/http"
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"time"
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)
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var (
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listeningAddress string
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barDomain float64
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barMean float64
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fooDomain float64
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// Create a histogram to track fictitious interservice RPC latency for three
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// distinct services.
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rpc_latency = metrics.NewHistogram(&metrics.HistogramSpecification{
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// Four distinct histogram buckets for values:
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// - equally-sized,
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// - 0 to 50, 50 to 100, 100 to 150, and 150 to 200.
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Starts: metrics.EquallySizedBucketsFor(0, 200, 4),
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// Create histogram buckets using an accumulating bucket, a bucket that
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// holds sample values subject to an eviction policy:
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// - 50 elements are allowed per bucket.
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// - Once 50 have been reached, the bucket empties 10 elements, averages the
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// evicted elements, and re-appends that back to the bucket.
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BucketBuilder: metrics.AccumulatingBucketBuilder(metrics.EvictAndReplaceWith(10, maths.Average), 50),
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// The histogram reports percentiles 1, 5, 50, 90, and 99.
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ReportablePercentiles: []float64{0.01, 0.05, 0.5, 0.90, 0.99},
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})
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rpc_calls = metrics.NewCounter()
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// If for whatever reason you are resistant to the idea of having a static
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// registry for metrics, which is a really bad idea when using Prometheus-
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// enabled library code, you can create your own.
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customRegistry = registry.NewRegistry()
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)
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func init() {
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flag.StringVar(&listeningAddress, "listeningAddress", ":8080", "The address to listen to requests on.")
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flag.Float64Var(&fooDomain, "random.fooDomain", 200, "The domain for the random parameter foo.")
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flag.Float64Var(&barDomain, "random.barDomain", 10, "The domain for the random parameter bar.")
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flag.Float64Var(&barMean, "random.barMean", 100, "The mean for the random parameter bar.")
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}
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func main() {
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flag.Parse()
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go func() {
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for {
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rpc_latency.Add(map[string]string{"service": "foo"}, rand.Float64()*fooDomain)
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rpc_calls.Increment(map[string]string{"service": "foo"})
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rpc_latency.Add(map[string]string{"service": "bar"}, (rand.NormFloat64()*barDomain)+barMean)
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rpc_calls.Increment(map[string]string{"service": "bar"})
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rpc_latency.Add(map[string]string{"service": "zed"}, rand.ExpFloat64())
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rpc_calls.Increment(map[string]string{"service": "zed"})
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time.Sleep(100 * time.Millisecond)
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}
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}()
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http.Handle(registry.ExpositionResource, customRegistry.Handler())
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http.ListenAndServe(listeningAddress, nil)
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}
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func init() {
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customRegistry.Register("rpc_latency_microseconds", "RPC latency.", registry.NilLabels, rpc_latency)
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customRegistry.Register("rpc_calls_total", "RPC calls.", registry.NilLabels, rpc_calls)
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}
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