prometheus/vendor/go.uber.org/goleak/options.go

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// Copyright (c) 2017 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package goleak
import (
"strings"
"time"
"go.uber.org/goleak/internal/stack"
)
// Option lets users specify custom verifications.
type Option interface {
apply(*opts)
}
// We retry up to 20 times if we can't find the goroutine that
// we are looking for. In between each attempt, we will sleep for
// a short while to let any running goroutines complete.
const _defaultRetries = 20
type opts struct {
filters []func(stack.Stack) bool
maxRetries int
maxSleep time.Duration
}
// optionFunc lets us easily write options without a custom type.
type optionFunc func(*opts)
func (f optionFunc) apply(opts *opts) { f(opts) }
// IgnoreTopFunction ignores any goroutines where the specified function
// is at the top of the stack. The function name should be fully qualified,
// e.g., go.uber.org/goleak.IgnoreTopFunction
func IgnoreTopFunction(f string) Option {
return addFilter(func(s stack.Stack) bool {
return s.FirstFunction() == f
})
}
func maxSleep(d time.Duration) Option {
return optionFunc(func(opts *opts) {
opts.maxSleep = d
})
}
func addFilter(f func(stack.Stack) bool) Option {
return optionFunc(func(opts *opts) {
opts.filters = append(opts.filters, f)
})
}
func buildOpts(options ...Option) *opts {
opts := &opts{
maxRetries: _defaultRetries,
maxSleep: 100 * time.Millisecond,
}
opts.filters = append(opts.filters,
isTestStack,
isSyscallStack,
isStdLibStack,
isTraceStack,
)
for _, option := range options {
option.apply(opts)
}
return opts
}
func (vo *opts) filter(s stack.Stack) bool {
for _, filter := range vo.filters {
if filter(s) {
return true
}
}
return false
}
func (vo *opts) retry(i int) bool {
if i >= vo.maxRetries {
return false
}
d := time.Duration(int(time.Microsecond) << uint(i))
if d > vo.maxSleep {
d = vo.maxSleep
}
time.Sleep(d)
return true
}
// isTestStack is a default filter installed to automatically skip goroutines
// that the testing package runs while the user's tests are running.
func isTestStack(s stack.Stack) bool {
// Until go1.7, the main goroutine ran RunTests, which started
// the test in a separate goroutine and waited for that test goroutine
// to end by waiting on a channel.
// Since go1.7, a separate goroutine is started to wait for signals.
// T.Parallel is for parallel tests, which are blocked until all serial
// tests have run with T.Parallel at the top of the stack.
switch s.FirstFunction() {
case "testing.RunTests", "testing.(*T).Run", "testing.(*T).Parallel":
// In pre1.7 and post-1.7, background goroutines started by the testing
// package are blocked waiting on a channel.
return strings.HasPrefix(s.State(), "chan receive")
}
return false
}
func isSyscallStack(s stack.Stack) bool {
// Typically runs in the background when code uses CGo:
// https://github.com/golang/go/issues/16714
return s.FirstFunction() == "runtime.goexit" && strings.HasPrefix(s.State(), "syscall")
}
func isStdLibStack(s stack.Stack) bool {
// Importing os/signal starts a background goroutine.
// The name of the function at the top has changed between versions.
if f := s.FirstFunction(); f == "os/signal.signal_recv" || f == "os/signal.loop" {
return true
}
// Using signal.Notify will start a runtime goroutine.
return strings.Contains(s.Full(), "runtime.ensureSigM")
}
func isTraceStack(s stack.Stack) bool {
if f := s.FirstFunction(); f != "runtime.goparkunlock" {
return false
}
return strings.Contains(s.Full(), "runtime.ReadTrace")
}