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* run latest vndr so as to collect more LICENSE files * remove unused packages * vendor github.com/philhofer/fwd with LICENSE.md (MIT) * vendor github.com/bsphere/le_go with LICENSE (MIT) Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
68 lines
2.4 KiB
Markdown
68 lines
2.4 KiB
Markdown
go-metrics
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==========
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This library provides a `metrics` package which can be used to instrument code,
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expose application metrics, and profile runtime performance in a flexible manner.
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Sinks
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=====
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The `metrics` package makes use of a `MetricSink` interface to support delivery
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to any type of backend. Currently the following sinks are provided:
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* StatsiteSink : Sinks to a statsite instance (TCP)
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* StatsdSink: Sinks to a statsd / statsite instance (UDP)
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* InmemSink : Provides in-memory aggregation, can be used to export stats
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* FanoutSink : Sinks to multiple sinks. Enables writing to multiple statsite instances for example.
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* BlackholeSink : Sinks to nowhere
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In addition to the sinks, the `InmemSignal` can be used to catch a signal,
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and dump a formatted output of recent metrics. For example, when a process gets
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a SIGUSR1, it can dump to stderr recent performance metrics for debugging.
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Examples
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========
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Here is an example of using the package:
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func SlowMethod() {
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// Profiling the runtime of a method
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defer metrics.MeasureSince([]string{"SlowMethod"}, time.Now())
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}
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// Configure a statsite sink as the global metrics sink
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sink, _ := metrics.NewStatsiteSink("statsite:8125")
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metrics.NewGlobal(metrics.DefaultConfig("service-name"), sink)
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// Emit a Key/Value pair
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metrics.EmitKey([]string{"questions", "meaning of life"}, 42)
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Here is an example of setting up an signal handler:
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// Setup the inmem sink and signal handler
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inm := NewInmemSink(10*time.Second, time.Minute)
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sig := DefaultInmemSignal(inm)
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metrics.NewGlobal(metrics.DefaultConfig("service-name"), inm)
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// Run some code
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inm.SetGauge([]string{"foo"}, 42)
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inm.EmitKey([]string{"bar"}, 30)
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inm.IncrCounter([]string{"baz"}, 42)
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inm.IncrCounter([]string{"baz"}, 1)
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inm.IncrCounter([]string{"baz"}, 80)
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inm.AddSample([]string{"method", "wow"}, 42)
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inm.AddSample([]string{"method", "wow"}, 100)
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inm.AddSample([]string{"method", "wow"}, 22)
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....
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When a signal comes in, output like the following will be dumped to stderr:
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[2014-01-28 14:57:33.04 -0800 PST][G] 'foo': 42.000
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[2014-01-28 14:57:33.04 -0800 PST][P] 'bar': 30.000
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[2014-01-28 14:57:33.04 -0800 PST][C] 'baz': Count: 3 Min: 1.000 Mean: 41.000 Max: 80.000 Stddev: 39.509
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[2014-01-28 14:57:33.04 -0800 PST][S] 'method.wow': Count: 3 Min: 22.000 Mean: 54.667 Max: 100.000 Stddev: 40.513
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