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// Copyright 2016 CoreOS, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package runtime
import (
"context"
"fmt"
"os"
"strings"
"sync"
)
var (
ErrNoExist = fmt.Errorf("failpoint: failpoint does not exist")
ErrDisabled = fmt.Errorf("failpoint: failpoint is disabled")
failpoints map[string]*Failpoint
failpointsMu sync.RWMutex
envTerms map[string]string
)
func init() {
failpoints = make(map[string]*Failpoint)
envTerms = make(map[string]string)
if s := os.Getenv("GOFAIL_FAILPOINTS"); len(s) > 0 {
// format is <FAILPOINT>=<TERMS>[;<FAILPOINT>=<TERMS>;...]
for _, fp := range strings.Split(s, ";") {
fpTerm := strings.Split(fp, "=")
if len(fpTerm) != 2 {
fmt.Printf("bad failpoint %q\n", fp)
os.Exit(1)
}
envTerms[fpTerm[0]] = fpTerm[1]
}
}
if s := os.Getenv("GOFAIL_HTTP"); len(s) > 0 {
if err := serve(s); err != nil {
fmt.Println(err)
os.Exit(1)
}
}
}
// Enable sets a failpoint to a given failpoint description.
func Enable(failpath, inTerms string) error {
unlock, err := enableAndLock(failpath, inTerms)
if unlock != nil {
unlock()
}
return err
}
// enableAndLock enables a failpoint and returns a function to unlock it
func enableAndLock(failpath, inTerms string) (func(), error) {
t, err := newTerms(failpath, inTerms)
if err != nil {
fmt.Printf("failed to enable \"%s=%s\" (%v)\n", failpath, inTerms, err)
return nil, err
}
failpointsMu.RLock()
fp := failpoints[failpath]
failpointsMu.RUnlock()
if fp == nil {
return nil, ErrNoExist
}
fp.mu.Lock()
fp.t = t
fp.released = false
return func() { fp.mu.Unlock() }, nil
}
// Disable stops a failpoint from firing.
func Disable(failpath string) error {
failpointsMu.RLock()
fp := failpoints[failpath]
failpointsMu.RUnlock()
if fp == nil {
return ErrNoExist
}
fp.cmu.RLock()
cancel := fp.cancel
donec := fp.donec
fp.cmu.RUnlock()
if cancel != nil && donec != nil {
cancel()
<-donec
fp.cmu.Lock()
fp.ctx, fp.cancel = context.WithCancel(context.Background())
fp.donec = make(chan struct{})
fp.released = true
fp.cmu.Unlock()
}
fp.mu.Lock()
defer fp.mu.Unlock()
if fp.t == nil {
return ErrDisabled
}
fp.t = nil
return nil
}
// Status gives the current setting for the failpoint
func Status(failpath string) (string, error) {
failpointsMu.RLock()
fp := failpoints[failpath]
failpointsMu.RUnlock()
if fp == nil {
return "", ErrNoExist
}
fp.mu.RLock()
t := fp.t
fp.mu.RUnlock()
if t == nil {
return "", ErrDisabled
}
return t.desc, nil
}
func List() []string {
failpointsMu.RLock()
ret := make([]string, 0, len(failpoints))
for fp := range failpoints {
ret = append(ret, fp)
}
failpointsMu.RUnlock()
return ret
}
func register(failpath string, fp *Failpoint) {
failpointsMu.Lock()
failpoints[failpath] = fp
failpointsMu.Unlock()
if t, ok := envTerms[failpath]; ok {
Enable(failpath, t)
}
}
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