initial commit

process.go

@@ -0,0 +1,75 @@
+package process
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"time"
+)
+
+type Process struct {
+	Label      string
+	ExecPath   string
+	Args       []string
+	Pid        int
+	StartTime  time.Time
+	EndTime    time.Time
+	Cmd        *exec.Cmd        `json:"-"`
+	ExitState  *os.ProcessState `json:"-"`
+	InputFile  io.Reader        `json:"-"`
+	OutputFile io.WriteCloser   `json:"-"`
+	WaitCh     chan struct{}    `json:"-"`
+}
+
+// execPath: command name
+// args: args to command. (should not include name)
+func StartProcess(label string, execPath string, args []string, inFile io.Reader, outFile io.WriteCloser) (*Process, error) {
+	cmd := exec.Command(execPath, args...)
+	cmd.Stdout = outFile
+	cmd.Stderr = outFile
+	cmd.Stdin = inFile
+	if err := cmd.Start(); err != nil {
+		return nil, err
+	}
+	proc := &Process{
+		Label:      label,
+		ExecPath:   execPath,
+		Args:       args,
+		Pid:        cmd.Process.Pid,
+		StartTime:  time.Now(),
+		Cmd:        cmd,
+		ExitState:  nil,
+		InputFile:  inFile,
+		OutputFile: outFile,
+		WaitCh:     make(chan struct{}),
+	}
+	go func() {
+		err := proc.Cmd.Wait()
+		if err != nil {
+			fmt.Printf("Process exit: %v\n", err)
+			if exitError, ok := err.(*exec.ExitError); ok {
+				proc.ExitState = exitError.ProcessState
+			}
+		}
+		proc.ExitState = proc.Cmd.ProcessState
+		proc.EndTime = time.Now() // TODO make this goroutine-safe
+		err = proc.OutputFile.Close()
+		if err != nil {
+			fmt.Printf("Error closing output file for %v: %v\n", proc.Label, err)
+		}
+		close(proc.WaitCh)
+	}()
+	return proc, nil
+}
+
+func (proc *Process) StopProcess() error {
+	defer proc.OutputFile.Close()
+	if kill {
+		fmt.Printf("Killing process %v\n", proc.Cmd.Process)
+		return proc.Cmd.Process.Kill()
+	} else {
+		fmt.Printf("Stopping process %v\n", proc.Cmd.Process)
+		return proc.Cmd.Process.Signal(os.Interrupt)
+	}
+}