Golang processes
From wikinotes
TODO:
- signal handling
- safely reading from stdin
- piping outputs to inputs
- what about exit codes?
Documentation
os
https://pkg.go.dev/os@go1.18.3
Current Process
import "os" import "os/user" os.Executable() os.Getpid() os.Getppid() os.Getuid() os.Getgid() os.Exit(1) // exit process with exitcode '1' // environment envvars := os.Environ() // ["FOO=bar", "BAR=baz", ...] pwd, err := os.Getwd() // get current pwd/cwd user.Current() // 'will'
Manage Processes
import "syscall" import "os" import "os/signal" proc := os.Process.FindProcess(1234) // find process with pid proc.Kill() // kill process (-9/SIGKILL) proc.Signal(os.Iterrupt) // send SIGINT to process (looks like you can use any syscall.SIG*) proc.Wait() // wait for process to end syscall.Kill(1234, syscall.SIGINT) // send SIGINT to pid 1234
Subprocess
high-level/friendly
// 1. create command, // 2. modify it's exec.Cmd struct (ex. stdin,stdout) // 3. run process // 4. cmd.ProcessState has info about process, including exitcode import "os" import "os/exec" cmd := exec.Command("netstat", "-an") stdout, err := cmd.Output() reader, err := cmd.StderrPipe() reader, err := cmd.StdoutPipe() writer, err := cmd.StdinPipe() err := cmd.Run() // run and wait err := cmd.Start() // run, don't wait err := cmd.Wait() // wait for proces to finishlow-level
// 1. create ProcAttr // 2. start process // 3. wait for process // 4. get info from it's ProcessState import "os" import "os/exec" psAttr := os.ProcAttr{ Dir: "/var/tmp", Env: []string{"FOO=BAR"}, } ps := os.StartProcess("netstat", []string{"-a", "-n"}, psAttr) pstate, err := ps.Wait() pstate.ExitCode()