Add mrun option to run multiple targets at once

iBazel currently only supports "run" for single target. Running multiple
targets requires separate Bazel command executions and busy waiting for
build processes.

Implement "mrun" command which takes in arbitrary number of targets, and
run all of them at once. We can pass in corresponding arguments with
prefix "--arg=".

bazel/bazel.go

@@ -207,7 +207,7 @@ func (b *bazel) Test(args ...string) (*bytes.Buffer, error) {
 func (b *bazel) Run(args ...string) (*exec.Cmd, *bytes.Buffer, error) {
 	b.WriteToStderr(true)
 	b.WriteToStdout(true)
-	stdoutBuffer, stderrBuffer := b.newCommand("run", args...)
+	stdoutBuffer, stderrBuffer := b.newCommand("run", append(b.args, args...)...)
 	b.cmd.Stdin = os.Stdin
 
 	_, _ = stdoutBuffer.Write(stderrBuffer.Bytes())

ibazel/command/command.go

@@ -31,15 +31,15 @@ var bazelNew = bazel.New
 // Command is an object that wraps the logic of running a task in Bazel and
 // manipulating it.
 type Command interface {
-	Start() (*bytes.Buffer, error)
+	Start(logFile *os.File) (*bytes.Buffer, error)
 	Terminate()
-	NotifyOfChanges() *bytes.Buffer
+	NotifyOfChanges(logFile *os.File) *bytes.Buffer
 	IsSubprocessRunning() bool
 }
 
 // start will be called by most implementations since this logic is extremely
 // common.
-func start(b bazel.Bazel, target string, args []string) (*bytes.Buffer, *exec.Cmd) {
+func start(b bazel.Bazel, target string, args []string, logFile *os.File) (*bytes.Buffer, *exec.Cmd) {
 	tmpfile, err := ioutil.TempFile("", "bazel_script_path")
 	if err != nil {
 		fmt.Print(err)
@@ -57,8 +57,13 @@ func start(b bazel.Bazel, target string, args []string) (*bytes.Buffer, *exec.Cm
 	// Now that we have built the target, construct a executable form of it for
 	// execution in a go routine.
 	cmd := execCommand(runScriptPath, args...)
-	cmd.Stdout = os.Stdout
-	cmd.Stderr = os.Stderr
+	if logFile != nil {
+		cmd.Stdout = logFile
+		cmd.Stderr = logFile
+	} else {
+		cmd.Stdout = os.Stdout
+		cmd.Stderr = os.Stderr
+	}
 
 	// Set a process group id (PGID) on the subprocess. This is
 	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}

ibazel/command/default_command.go

@@ -55,14 +55,14 @@ func (c *defaultCommand) Terminate() {
 	c.cmd = nil
 }
 
-func (c *defaultCommand) Start() (*bytes.Buffer, error) {
+func (c *defaultCommand) Start(logFile *os.File) (*bytes.Buffer, error) {
 	b := bazelNew()
 	b.SetArguments(c.bazelArgs)
 
 	b.WriteToStderr(true)
 	b.WriteToStdout(true)
 
-	outputBuffer, foo := start(b, c.target, c.args)
+	outputBuffer, foo := start(b, c.target, c.args, logFile)
 	c.cmd = foo
 
 	c.cmd.Env = os.Environ()
@@ -76,10 +76,10 @@ func (c *defaultCommand) Start() (*bytes.Buffer, error) {
 	return outputBuffer, nil
 }
 
-func (c *defaultCommand) NotifyOfChanges() *bytes.Buffer {
+func (c *defaultCommand) NotifyOfChanges(logFile *os.File) *bytes.Buffer {
 	c.Terminate()
-	c.Start()
-	return nil
+	outputBuffer, _ := c.Start(logFile)
+	return outputBuffer
 }
 
 func (c *defaultCommand) IsSubprocessRunning() bool {

ibazel/command/notify_command.go

@@ -57,14 +57,14 @@ func (c *notifyCommand) Terminate() {
 	c.cmd = nil
 }
 
-func (c *notifyCommand) Start() (*bytes.Buffer, error) {
+func (c *notifyCommand) Start(logFile *os.File) (*bytes.Buffer, error) {
 	b := bazelNew()
 	b.SetArguments(c.bazelArgs)
 
 	b.WriteToStderr(true)
 	b.WriteToStdout(true)
 
-	outputBuffer, foo := start(b, c.target, c.args)
+	outputBuffer, foo := start(b, c.target, c.args, logFile)
 	c.cmd = foo
 	// Keep the writer around.
 	var err error
@@ -84,7 +84,7 @@ func (c *notifyCommand) Start() (*bytes.Buffer, error) {
 	return outputBuffer, nil
 }
 
-func (c *notifyCommand) NotifyOfChanges() *bytes.Buffer {
+func (c *notifyCommand) NotifyOfChanges(logFile *os.File) *bytes.Buffer {
 	b := bazelNew()
 	b.SetArguments(c.bazelArgs)