mirror of
https://github.com/kubernetes/kubectl.git
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133 lines
3 KiB
Go
133 lines
3 KiB
Go
/*
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Copyright 2017 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package cmd
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import (
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"fmt"
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"io"
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"os"
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"os/signal"
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"runtime"
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"runtime/pprof"
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"runtime/trace"
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"github.com/spf13/pflag"
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)
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var (
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profileName string
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profileOutput string
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)
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func addProfilingFlags(flags *pflag.FlagSet) {
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flags.StringVar(&profileName, "profile", "none", "Name of profile to capture. One of (none|cpu|heap|goroutine|threadcreate|block|mutex|trace)")
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flags.StringVar(&profileOutput, "profile-output", "profile.pprof", "Name of the file to write the profile to")
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}
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// initProfiling inits profiling and returns a function to be called on exit to flush and close.
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func initProfiling() (func() error, error) {
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var (
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f *os.File
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err error
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)
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switch profileName {
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case "none":
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return nil, nil
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case "cpu":
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f, err = os.Create(profileOutput)
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if err != nil {
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return nil, err
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}
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err = pprof.StartCPUProfile(f)
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if err != nil {
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f.Close() //nolint:errcheck
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return nil, err
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}
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// Block and mutex profiles need a call to Set{Block,Mutex}ProfileRate to
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// output anything. We choose to sample all events.
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case "block":
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runtime.SetBlockProfileRate(1)
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case "mutex":
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runtime.SetMutexProfileFraction(1)
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case "trace":
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f, err = os.Create(profileOutput)
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if err != nil {
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return nil, err
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}
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// Enable the CPU profiler. Samples will be captured in the execution trace.
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// This is the same rate value as used in pprof.StartCPUProfile.
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runtime.SetCPUProfileRate(100)
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if err := trace.Start(f); err != nil {
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f.Close() //nolint:errcheck
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return nil, err
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}
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default:
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// Check the profile name is valid.
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if profile := pprof.Lookup(profileName); profile == nil {
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return nil, fmt.Errorf("unknown profile '%s'", profileName)
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}
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}
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// If the command is interrupted before the end (ctrl-c), flush the profiling files
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c := make(chan os.Signal, 1)
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signal.Notify(c, os.Interrupt)
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go func() {
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<-c
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flushProfiling(f) //nolint:errcheck
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os.Exit(0)
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}()
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return func() error {
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return flushProfiling(f)
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}, nil
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}
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func flushProfiling(output io.Closer) error {
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if output != nil {
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defer output.Close() //nolint:errcheck
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}
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switch profileName {
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case "none":
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return nil
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case "cpu":
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pprof.StopCPUProfile()
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case "trace":
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trace.Stop()
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runtime.SetCPUProfileRate(0)
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case "heap":
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runtime.GC()
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fallthrough
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default:
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profile := pprof.Lookup(profileName)
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if profile == nil {
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return nil
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}
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f, err := os.Create(profileOutput)
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if err != nil {
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return err
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}
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defer f.Close()
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profile.WriteTo(f, 0)
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}
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return nil
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}
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