|
9 | 9 |
|
10 | 10 | ```Go
|
11 | 11 |
|
12 |
| - d := flag.Bool("d", false, "Whether or not to launch in the background(like a daemon)") |
13 |
| - if *d { |
14 |
| - cmd := exec.Command(os.Args[0], |
15 |
| - "-close-fds", |
16 |
| - "-addr", *addr, |
17 |
| - "-call", *call, |
18 |
| - ) |
19 |
| - serr, err := cmd.StderrPipe() |
20 |
| - if err != nil { |
21 |
| - log.Fatalln(err) |
22 |
| - } |
23 |
| - err = cmd.Start() |
24 |
| - if err != nil { |
25 |
| - log.Fatalln(err) |
26 |
| - } |
27 |
| - s, err := ioutil.ReadAll(serr) |
28 |
| - s = bytes.TrimSpace(s) |
29 |
| - if bytes.HasPrefix(s, []byte("addr: ")) { |
30 |
| - fmt.Println(string(s)) |
31 |
| - cmd.Process.Release() |
32 |
| - } else { |
33 |
| - log.Printf("unexpected response from MarGo: `%s` error: `%v`\n", s, err) |
34 |
| - cmd.Process.Kill() |
35 |
| - } |
| 12 | +d := flag.Bool("d", false, "Whether or not to launch in the background(like a daemon)") |
| 13 | +if *d { |
| 14 | + cmd := exec.Command(os.Args[0], |
| 15 | + "-close-fds", |
| 16 | + "-addr", *addr, |
| 17 | + "-call", *call, |
| 18 | + ) |
| 19 | + serr, err := cmd.StderrPipe() |
| 20 | + if err != nil { |
| 21 | + log.Fatalln(err) |
36 | 22 | }
|
| 23 | + err = cmd.Start() |
| 24 | + if err != nil { |
| 25 | + log.Fatalln(err) |
| 26 | + } |
| 27 | + s, err := ioutil.ReadAll(serr) |
| 28 | + s = bytes.TrimSpace(s) |
| 29 | + if bytes.HasPrefix(s, []byte("addr: ")) { |
| 30 | + fmt.Println(string(s)) |
| 31 | + cmd.Process.Release() |
| 32 | + } else { |
| 33 | + log.Printf("unexpected response from MarGo: `%s` error: `%v`\n", s, err) |
| 34 | + cmd.Process.Kill() |
| 35 | + } |
| 36 | +} |
37 | 37 | ```
|
38 | 38 |
|
39 | 39 | - 另一种是利用syscall的方案,但是这个方案并不完善:
|
40 | 40 | ```Go
|
41 | 41 |
|
42 |
| - package main |
43 |
| - |
44 |
| - import ( |
45 |
| - "log" |
46 |
| - "os" |
47 |
| - "syscall" |
48 |
| - ) |
49 |
| - |
50 |
| - func daemon(nochdir, noclose int) int { |
51 |
| - var ret, ret2 uintptr |
52 |
| - var err uintptr |
53 |
| - |
54 |
| - darwin := syscall.OS == "darwin" |
55 |
| - |
56 |
| - // already a daemon |
57 |
| - if syscall.Getppid() == 1 { |
58 |
| - return 0 |
59 |
| - } |
60 |
| - |
61 |
| - // fork off the parent process |
62 |
| - ret, ret2, err = syscall.RawSyscall(syscall.SYS_FORK, 0, 0, 0) |
63 |
| - if err != 0 { |
64 |
| - return -1 |
65 |
| - } |
66 |
| - |
67 |
| - // failure |
68 |
| - if ret2 < 0 { |
69 |
| - os.Exit(-1) |
70 |
| - } |
71 |
| - |
72 |
| - // handle exception for darwin |
73 |
| - if darwin && ret2 == 1 { |
74 |
| - ret = 0 |
75 |
| - } |
76 |
| - |
77 |
| - // if we got a good PID, then we call exit the parent process. |
78 |
| - if ret > 0 { |
79 |
| - os.Exit(0) |
80 |
| - } |
81 |
| - |
82 |
| - /* Change the file mode mask */ |
83 |
| - _ = syscall.Umask(0) |
84 |
| - |
85 |
| - // create a new SID for the child process |
86 |
| - s_ret, s_errno := syscall.Setsid() |
87 |
| - if s_errno != 0 { |
88 |
| - log.Printf("Error: syscall.Setsid errno: %d", s_errno) |
89 |
| - } |
90 |
| - if s_ret < 0 { |
91 |
| - return -1 |
92 |
| - } |
93 |
| - |
94 |
| - if nochdir == 0 { |
95 |
| - os.Chdir("/") |
96 |
| - } |
97 |
| - |
98 |
| - if noclose == 0 { |
99 |
| - f, e := os.OpenFile("/dev/null", os.O_RDWR, 0) |
100 |
| - if e == nil { |
101 |
| - fd := f.Fd() |
102 |
| - syscall.Dup2(fd, os.Stdin.Fd()) |
103 |
| - syscall.Dup2(fd, os.Stdout.Fd()) |
104 |
| - syscall.Dup2(fd, os.Stderr.Fd()) |
105 |
| - } |
106 |
| - } |
107 |
| - |
| 42 | +package main |
| 43 | + |
| 44 | +import ( |
| 45 | + "log" |
| 46 | + "os" |
| 47 | + "syscall" |
| 48 | +) |
| 49 | + |
| 50 | +func daemon(nochdir, noclose int) int { |
| 51 | + var ret, ret2 uintptr |
| 52 | + var err uintptr |
| 53 | + |
| 54 | + darwin := syscall.OS == "darwin" |
| 55 | + |
| 56 | + // already a daemon |
| 57 | + if syscall.Getppid() == 1 { |
108 | 58 | return 0
|
109 |
| - } |
| 59 | + } |
| 60 | + |
| 61 | + // fork off the parent process |
| 62 | + ret, ret2, err = syscall.RawSyscall(syscall.SYS_FORK, 0, 0, 0) |
| 63 | + if err != 0 { |
| 64 | + return -1 |
| 65 | + } |
| 66 | + |
| 67 | + // failure |
| 68 | + if ret2 < 0 { |
| 69 | + os.Exit(-1) |
| 70 | + } |
| 71 | + |
| 72 | + // handle exception for darwin |
| 73 | + if darwin && ret2 == 1 { |
| 74 | + ret = 0 |
| 75 | + } |
| 76 | + |
| 77 | + // if we got a good PID, then we call exit the parent process. |
| 78 | + if ret > 0 { |
| 79 | + os.Exit(0) |
| 80 | + } |
| 81 | + |
| 82 | + /* Change the file mode mask */ |
| 83 | + _ = syscall.Umask(0) |
| 84 | + |
| 85 | + // create a new SID for the child process |
| 86 | + s_ret, s_errno := syscall.Setsid() |
| 87 | + if s_errno != 0 { |
| 88 | + log.Printf("Error: syscall.Setsid errno: %d", s_errno) |
| 89 | + } |
| 90 | + if s_ret < 0 { |
| 91 | + return -1 |
| 92 | + } |
| 93 | + |
| 94 | + if nochdir == 0 { |
| 95 | + os.Chdir("/") |
| 96 | + } |
| 97 | + |
| 98 | + if noclose == 0 { |
| 99 | + f, e := os.OpenFile("/dev/null", os.O_RDWR, 0) |
| 100 | + if e == nil { |
| 101 | + fd := f.Fd() |
| 102 | + syscall.Dup2(fd, os.Stdin.Fd()) |
| 103 | + syscall.Dup2(fd, os.Stdout.Fd()) |
| 104 | + syscall.Dup2(fd, os.Stderr.Fd()) |
| 105 | + } |
| 106 | + } |
| 107 | + |
| 108 | + return 0 |
| 109 | +} |
110 | 110 | ```
|
111 | 111 |
|
112 | 112 | 上面提出了两种实现Go的daemon方案,但是我还是不推荐大家这样去实现,因为官方还没有正式的宣布支持daemon,当然第一种方案目前来看是比较可行的,而且目前开源库skynet也在采用这个方案做daemon。
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