Refactoring: rename modules -> pkg

Reasons to change:

1. Shorter than 'modules'
2. More generally used by other Go projects
3. Corresponds to the naming of '$GOPATH/pkg' directory

pkg/process/manager.go

@@ -0,0 +1,127 @@
+// Copyright 2014 The Gogs Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package process
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"os/exec"
+	"time"
+
+	log "gopkg.in/clog.v1"
+)
+
+var (
+	ErrExecTimeout = errors.New("Process execution timeout")
+)
+
+// Common timeout.
+var (
+	// NOTE: could be custom in config file for default.
+	DEFAULT = 60 * time.Second
+)
+
+// Process represents a working process inherit from Gogs.
+type Process struct {
+	Pid         int64 // Process ID, not system one.
+	Description string
+	Start       time.Time
+	Cmd         *exec.Cmd
+}
+
+// List of existing processes.
+var (
+	curPid    int64 = 1
+	Processes []*Process
+)
+
+// Add adds a existing process and returns its PID.
+func Add(desc string, cmd *exec.Cmd) int64 {
+	pid := curPid
+	Processes = append(Processes, &Process{
+		Pid:         pid,
+		Description: desc,
+		Start:       time.Now(),
+		Cmd:         cmd,
+	})
+	curPid++
+	return pid
+}
+
+// Exec starts executing a command in given path, it records its process and timeout.
+func ExecDir(timeout time.Duration, dir, desc, cmdName string, args ...string) (string, string, error) {
+	if timeout == -1 {
+		timeout = DEFAULT
+	}
+
+	bufOut := new(bytes.Buffer)
+	bufErr := new(bytes.Buffer)
+
+	cmd := exec.Command(cmdName, args...)
+	cmd.Dir = dir
+	cmd.Stdout = bufOut
+	cmd.Stderr = bufErr
+	if err := cmd.Start(); err != nil {
+		return "", err.Error(), err
+	}
+
+	pid := Add(desc, cmd)
+	done := make(chan error)
+	go func() {
+		done <- cmd.Wait()
+	}()
+
+	var err error
+	select {
+	case <-time.After(timeout):
+		if errKill := Kill(pid); errKill != nil {
+			log.Error(4, "Exec(%d:%s): %v", pid, desc, errKill)
+		}
+		<-done
+		return "", ErrExecTimeout.Error(), ErrExecTimeout
+	case err = <-done:
+	}
+
+	Remove(pid)
+	return bufOut.String(), bufErr.String(), err
+}
+
+// Exec starts executing a command, it records its process and timeout.
+func ExecTimeout(timeout time.Duration, desc, cmdName string, args ...string) (string, string, error) {
+	return ExecDir(timeout, "", desc, cmdName, args...)
+}
+
+// Exec starts executing a command, it records its process and has default timeout.
+func Exec(desc, cmdName string, args ...string) (string, string, error) {
+	return ExecDir(-1, "", desc, cmdName, args...)
+}
+
+// Remove removes a process from list.
+func Remove(pid int64) {
+	for i, proc := range Processes {
+		if proc.Pid == pid {
+			Processes = append(Processes[:i], Processes[i+1:]...)
+			return
+		}
+	}
+}
+
+// Kill kills and removes a process from list.
+func Kill(pid int64) error {
+	for i, proc := range Processes {
+		if proc.Pid == pid {
+			if proc.Cmd != nil && proc.Cmd.Process != nil &&
+				proc.Cmd.ProcessState != nil && !proc.Cmd.ProcessState.Exited() {
+				if err := proc.Cmd.Process.Kill(); err != nil {
+					return fmt.Errorf("fail to kill process(%d/%s): %v", proc.Pid, proc.Description, err)
+				}
+			}
+			Processes = append(Processes[:i], Processes[i+1:]...)
+			return nil
+		}
+	}
+	return nil
+}