/
cmd.go
177 lines (154 loc) · 3.63 KB
/
cmd.go
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// Copyright 2016 Google Inc. All rights reserved.
// Use of this source code is governed by the Apache 2.0
// license that can be found in the LICENSE file.
package main
import (
"bytes"
"errors"
"flag"
"io"
"io/ioutil"
"log"
"os"
"os/exec"
"os/signal"
"strings"
"syscall"
)
var verbose = flag.Bool("v", false, "Pipe stdout/stderr from emulators")
func main() {
flag.Parse()
if err := syscall.Setpgid(os.Getpid(), os.Getpid()); err != nil {
log.Fatalf("setpgid: %v", err)
}
forwardSignals()
datastore := &Emulator{
Command: []string{"gcloud", "-q", "beta", "emulators", "pubsub", "start"},
EnvCommand: []string{"gcloud", "-q", "beta", "emulators", "pubsub", "env-init"},
ReadySentinel: "Server started, listening",
}
if err := datastore.Start(); err != nil {
log.Fatalf("Could not start datastore: %v", err)
}
pubsub := &Emulator{
Command: []string{"gcloud", "-q", "beta", "emulators", "datastore", "start", "--no-legacy"},
EnvCommand: []string{"gcloud", "-q", "beta", "emulators", "datastore", "env-init"},
ReadySentinel: "is now running",
}
if err := pubsub.Start(); err != nil {
log.Fatalf("Could not start pubsub: %v", err)
}
datastore.WaitReady()
pubsub.WaitReady()
env := os.Environ()
env = append(env, datastore.Env()...)
env = append(env, pubsub.Env()...)
cmd := exec.Command(flag.Args()[0], flag.Args()[1:]...)
cmd.SysProcAttr = sysprocattr()
cmd.Env = env
cmd.Stdin, cmd.Stdout, cmd.Stderr = os.Stdin, os.Stdout, os.Stderr
cmdErr := cmd.Run()
if err := datastore.Stop(); err != nil {
log.Fatalf("Could not stop datastore: %v", err)
}
if err := pubsub.Stop(); err != nil {
log.Fatalf("Could not stop pubsub: %v", err)
}
if cmdErr != nil {
log.Fatal(cmdErr)
}
}
func sysprocattr() *syscall.SysProcAttr {
return &syscall.SysProcAttr{
Setpgid: true,
Pgid: os.Getpid(),
}
}
type Emulator struct {
cmd *exec.Cmd
ready chan struct{}
Command []string
EnvCommand []string
ReadySentinel string
}
func (e *Emulator) Start() error {
if e.ready != nil {
return errors.New("already started")
}
e.ready = make(chan struct{})
e.cmd = exec.Command(e.Command[0], e.Command[1:]...)
e.cmd.SysProcAttr = sysprocattr()
out := ioutil.Discard
if *verbose {
out = os.Stderr
}
e.cmd.Stderr = &watchFor{
base: out,
sentinel: e.ReadySentinel,
c: e.ready,
}
if *verbose {
e.cmd.Stdout = os.Stdout
}
return e.cmd.Start()
}
func (e *Emulator) WaitReady() {
<-e.ready
}
func (e *Emulator) Stop() error {
if err := syscall.Kill(-os.Getpid(), syscall.SIGTERM); err != nil {
return err
}
e.cmd.Wait()
return nil
}
func (e *Emulator) Env() []string {
cmd := exec.Command(e.EnvCommand[0], e.EnvCommand[1:]...)
out, err := cmd.CombinedOutput()
if err != nil {
log.Fatalf("could not get env: %v", err)
}
env := strings.Split(string(out), "\n")
for i, v := range env {
env[i] = strings.Replace(v, "export ", "", -1)
}
return env
}
type watchFor struct {
base io.Writer
buf bytes.Buffer
sentinel string
c chan struct{}
done bool
}
func (r *watchFor) Write(data []byte) (n int, err error) {
n, err = r.base.Write(data)
if r.done || err != nil {
return
}
n, err = r.buf.Write(data)
if strings.Contains(r.buf.String(), r.sentinel) {
close(r.c)
r.done = true
}
return
}
func forwardSignals() {
pgroup, err := os.FindProcess(-os.Getpid())
if err != nil {
log.Fatalf("Could not find proc 0: %v", err)
}
sigch := make(chan os.Signal, 1)
go func() {
select {
case sig := <-sigch:
// Forward the signal.
pgroup.Signal(sig)
}
}()
signal.Notify(sigch,
syscall.SIGINT,
syscall.SIGTERM,
syscall.SIGHUP,
)
}