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start.go
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start.go
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package main
import (
"errors"
"fmt"
"os"
"os/signal"
"path/filepath"
"strconv"
"strings"
"sync"
"syscall"
"time"
)
const defaultPort = 5000
const defaultShutdownGraceTime = 3
var flagPort int
var flagConcurrency string
var flagRestart bool
var flagNoColor bool
var flagShutdownGraceTime int
var envs envFiles
var cmdStart = &Command{
Run: runStart,
Usage: "start [process name] [-f procfile] [-e env] [-p port] [-c concurrency] [-r] [-t shutdown_grace_time] [-n]",
Short: "Start the application",
Long: `
Start the application specified by a Procfile. The directory containing the
Procfile is used as the working directory.
The following options are available:
-f procfile Set the Procfile. Defaults to './Procfile'.
-e env Add an environment file, containing variables in 'KEY=value', or
'export KEY=value', form. These variables will be set in the
environment of each process. If no environment files are
specified, a file called .env is used if it exists.
-p port Sets the base port number; each process will have a PORT variable
in its environment set to a unique value based on this. This may
also be set via a PORT variable in the environment, or in an
environment file, and otherwise defaults to 5000.
-c concurrency
Start a specific number of instances of each process. The
argument should be in the format 'foo=1,bar=2,baz=0'. Use the
name 'all' to set the default number of instances. By default,
one instance of each process is started.
-r Restart a process which exits. Without this, if a process exits,
forego will kill all other processes and exit.
-t shutdown_grace_time
Set the shutdown grace time that each process is given after
being asked to stop. Once this grace time expires, the process is
forcibly terminated. By default, it is 3 seconds.
-n Do not colorize output lines.
If there is a file named .forego in the current directory, it will be read in
the same way as an environment file, and the values of variables procfile, port,
concurrency, and shutdown_grace_time used to change the corresponding default
values.
Examples:
# start every process
forego start
# start only the web process
forego start web
# start every process specified in Procfile.test, with the environment specified in .env.test
forego start -f Procfile.test -e .env.test
# start every process, with a timeout of 30 seconds
forego start -t 30
`,
}
func init() {
cmdStart.Flag.StringVar(&flagProcfile, "f", "Procfile", "procfile")
cmdStart.Flag.Var(&envs, "e", "env")
cmdStart.Flag.IntVar(&flagPort, "p", defaultPort, "port")
cmdStart.Flag.StringVar(&flagConcurrency, "c", "", "concurrency")
cmdStart.Flag.BoolVar(&flagRestart, "r", false, "restart")
cmdStart.Flag.IntVar(&flagShutdownGraceTime, "t", defaultShutdownGraceTime, "shutdown grace time")
cmdStart.Flag.BoolVar(&flagNoColor, "n", false, "no colorizing")
err := readConfigFile(".forego", &flagProcfile, &flagPort, &flagConcurrency, &flagShutdownGraceTime)
handleError(err)
}
func readConfigFile(config_path string, flagProcfile *string, flagPort *int, flagConcurrency *string, flagShutdownGraceTime *int) error {
config, err := ReadConfig(config_path)
if config["procfile"] != "" {
*flagProcfile = config["procfile"]
} else {
*flagProcfile = "Procfile"
}
if config["port"] != "" {
*flagPort, err = strconv.Atoi(config["port"])
} else {
*flagPort = defaultPort
}
if config["shutdown_grace_time"] != "" {
*flagShutdownGraceTime, err = strconv.Atoi(config["shutdown_grace_time"])
} else {
*flagShutdownGraceTime = defaultShutdownGraceTime
}
*flagConcurrency = config["concurrency"]
return err
}
func parseConcurrency(value string) (map[string]int, error) {
concurrency := map[string]int{}
if strings.TrimSpace(value) == "" {
return concurrency, nil
}
parts := strings.Split(value, ",")
for _, part := range parts {
if !strings.Contains(part, "=") {
return concurrency, errors.New("Concurrency should be in the format: foo=1,bar=2")
}
nameValue := strings.Split(part, "=")
n, v := strings.TrimSpace(nameValue[0]), strings.TrimSpace(nameValue[1])
if n == "" || v == "" {
return concurrency, errors.New("Concurrency should be in the format: foo=1,bar=2")
}
numProcs, err := strconv.ParseInt(v, 10, 16)
if err != nil {
return concurrency, err
}
concurrency[n] = int(numProcs)
}
return concurrency, nil
}
type Forego struct {
outletFactory *OutletFactory
teardown, teardownNow Barrier // signal shutting down
wg sync.WaitGroup
}
func (f *Forego) monitorInterrupt() {
handler := make(chan os.Signal, 1)
signal.Notify(handler, syscall.SIGALRM, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM)
first := true
for sig := range handler {
switch sig {
case syscall.SIGINT:
fmt.Println(" | ctrl-c detected")
fallthrough
default:
f.teardown.Fall()
if !first {
f.teardownNow.Fall()
}
first = false
}
}
}
func basePort(env Env) (int, error) {
if flagPort != defaultPort {
return flagPort, nil
} else if env["PORT"] != "" {
return strconv.Atoi(env["PORT"])
} else if os.Getenv("PORT") != "" {
return strconv.Atoi(os.Getenv("PORT"))
}
return defaultPort, nil
}
func (f *Forego) startProcess(idx, procNum int, proc ProcfileEntry, env Env, of *OutletFactory) {
port, err := basePort(env)
if err != nil {
panic(err)
}
port = port + (idx * 100)
const interactive = false
workDir := filepath.Dir(flagProcfile)
ps := NewProcess(workDir, proc.Command, env, interactive)
procName := fmt.Sprint(proc.Name, ".", procNum+1)
ps.Env["PORT"] = strconv.Itoa(port)
ps.Stdin = nil
stdout, err := ps.StdoutPipe()
if err != nil {
panic(err)
}
stderr, err := ps.StderrPipe()
if err != nil {
panic(err)
}
pipeWait := new(sync.WaitGroup)
pipeWait.Add(2)
go of.LineReader(pipeWait, procName, idx, stdout, false)
go of.LineReader(pipeWait, procName, idx, stderr, true)
of.SystemOutput(fmt.Sprintf("starting %s on port %d", procName, port))
finished := make(chan struct{}) // closed on process exit
err = ps.Start()
if err != nil {
f.teardown.Fall()
of.SystemOutput(fmt.Sprint("Failed to start ", procName, ": ", err))
return
}
f.wg.Add(1)
go func() {
defer f.wg.Done()
defer close(finished)
pipeWait.Wait()
ps.Wait()
}()
f.wg.Add(1)
go func() {
defer f.wg.Done()
select {
case <-finished:
if flagRestart {
f.startProcess(idx, procNum, proc, env, of)
} else {
f.teardown.Fall()
}
case <-f.teardown.Barrier():
// Forego tearing down
if !osHaveSigTerm {
of.SystemOutput(fmt.Sprintf("Killing %s", procName))
ps.Process.Kill()
return
}
of.SystemOutput(fmt.Sprintf("sending SIGTERM to %s", procName))
ps.SendSigTerm()
// Give the process a chance to exit, otherwise kill it.
select {
case <-f.teardownNow.Barrier():
of.SystemOutput(fmt.Sprintf("Killing %s", procName))
ps.SendSigKill()
case <-finished:
}
}
}()
}
func runStart(cmd *Command, args []string) {
pf, err := ReadProcfile(flagProcfile)
handleError(err)
concurrency, err := parseConcurrency(flagConcurrency)
handleError(err)
env, err := loadEnvs(envs)
handleError(err)
of := NewOutletFactory()
of.Padding = pf.LongestProcessName(concurrency)
f := &Forego{
outletFactory: of,
}
go f.monitorInterrupt()
// When teardown fires, start the grace timer
f.teardown.FallHook = func() {
go func() {
time.Sleep(time.Duration(flagShutdownGraceTime) * time.Second)
of.SystemOutput("Grace time expired")
f.teardownNow.Fall()
}()
}
var singleton string = ""
if len(args) > 0 {
singleton = args[0]
if !pf.HasProcess(singleton) {
of.ErrorOutput(fmt.Sprintf("no such process: %s", singleton))
}
}
defaultConcurrency := 1
var all bool
for name, num := range concurrency {
if name == "all" {
defaultConcurrency = num
all = true
}
}
for idx, proc := range pf.Entries {
numProcs := defaultConcurrency
if len(concurrency) > 0 {
if value, ok := concurrency[proc.Name]; ok {
numProcs = value
} else if !all {
continue
}
}
for i := 0; i < numProcs; i++ {
if (singleton == "") || (singleton == proc.Name) {
f.startProcess(idx, i, proc, env, of)
}
}
}
<-f.teardown.Barrier()
f.wg.Wait()
}