75 lines
2.0 KiB
Go
75 lines
2.0 KiB
Go
/*
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* Copyright 2020 The Dragonfly Authors
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*
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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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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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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 pidfile provides structure and helper functions to create and remove
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// PID file. A PID file is usually a file used to store the process ID of a
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// running process.
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package pidfile // copy from "github.com/docker/docker/pkg/pidfile"
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import (
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"fmt"
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"io/ioutil"
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"os"
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"path/filepath"
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"strconv"
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"strings"
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"github.com/shirou/gopsutil/v3/process"
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)
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// PIDFile is a file used to store the process ID of a running process.
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type PIDFile struct {
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path string
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}
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func IsProcessExistsByPIDFile(path string) (bool, error) {
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pidByte, err := ioutil.ReadFile(path)
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if os.IsNotExist(err) {
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return false, nil
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}
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if err != nil {
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return false, err
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}
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pid, err := strconv.ParseInt(strings.TrimSpace(string(pidByte)), 10, 32)
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if err != nil {
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return false, err
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}
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return process.PidExists(int32(pid))
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}
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// New creates a PIDfile using the specified path.
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func New(path string) (*PIDFile, error) {
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if ok, err := IsProcessExistsByPIDFile(path); ok {
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return nil, fmt.Errorf("process already exists")
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} else if err != nil {
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return nil, err
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}
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// Note MkdirAll returns nil if a directory already exists
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if err := os.MkdirAll(filepath.Dir(path), os.FileMode(0755)); err != nil {
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return nil, err
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}
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if err := ioutil.WriteFile(path, []byte(fmt.Sprintf("%d", os.Getpid())), 0644); err != nil {
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return nil, err
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}
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return &PIDFile{path: path}, nil
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}
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// Remove removes the PIDFile.
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func (file PIDFile) Remove() error {
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return os.Remove(file.path)
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}
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