Merge pull request #2 from edwarnicke/multiwriter

Enable WithStdout and WithStderr multiplexing

exechelper.go

@@ -25,12 +25,12 @@ import (
 	"github.com/google/shlex"
 )
 
-// Run - Creates a exec.Prepare using cmdStr.  Runs exec.Prepare.Run and returns the resulting error
+// Run - Creates a exec.Cmd using cmdStr.  Runs exec.Cmd.Run and returns the resulting error
 func Run(cmdStr string, options ...*Option) error {
 	return <-Start(cmdStr, options...)
 }
 
-// Start - Creates an exec.Prepare cmdStr.  Runs exec.Prepare.Start.
+// Start - Creates an exec.Cmd cmdStr.  Runs exec.Cmd.Start.
 func Start(cmdStr string, options ...*Option) <-chan error {
 	errCh := make(chan error, 1)
 
@@ -87,7 +87,7 @@ func Start(cmdStr string, options ...*Option) <-chan error {
 	return errCh
 }
 
-// Output - Creates a exec.Prepare using cmdStr.  Runs exec.Prepare.Output and returns the resulting output as []byte and error
+// Output - Creates a exec.Cmd using cmdStr.  Runs exec.Cmd.Output and returns the resulting output as []byte and error
 func Output(cmdStr string, options ...*Option) ([]byte, error) {
 	buffer := bytes.NewBuffer([]byte{})
 	options = append(options, WithStdout(buffer))
@@ -97,7 +97,7 @@ func Output(cmdStr string, options ...*Option) ([]byte, error) {
 	return buffer.Bytes(), nil
 }
 
-// CombinedOutput - Creates a exec.Prepare using cmdStr.  Runs exec.Prepare.CombinedOutput and returns the resulting output as []byte and error
+// CombinedOutput - Creates a exec.Cmd using cmdStr.  Runs exec.Cmd.CombinedOutput and returns the resulting output as []byte and error
 func CombinedOutput(cmdStr string, options ...*Option) ([]byte, error) {
 	buffer := bytes.NewBuffer([]byte{})
 	options = append(options, WithStdout(buffer), WithStderr(buffer))

exechelper_test.go

@@ -93,6 +93,25 @@ func TestWithStdin(t *testing.T) {
 	assert.Equal(t, testStr, strings.TrimSpace(string(b)))
 }
 
+func TestWithStdout(t *testing.T) {
+	buffer := bytes.NewBuffer([]byte{})
+	output, err := exechelper.Output("ls", exechelper.WithStdout(buffer))
+	assert.NoError(t, err)
+	assert.Equal(t, string(output), buffer.String())
+}
+
+func TestWithStderr(t *testing.T) {
+	buffer1 := bytes.NewBuffer([]byte{})
+	buffer2 := bytes.NewBuffer([]byte{})
+	err := exechelper.Run("ls fdhdhdhahdr",
+		exechelper.WithStderr(buffer1),
+		exechelper.WithStderr(buffer2),
+	)
+	assert.Error(t, err)
+	assert.True(t, buffer1.Len() > 0)
+	assert.Equal(t, buffer1.String(), buffer2.String())
+}
+
 func TestWithEnvMap(t *testing.T) {
 	// Try one
 	key1 := "key1"

options.go

@@ -57,7 +57,7 @@ func WithArgs(args ...string) *Option {
 	})
 }
 
-// WithDir - Option that will create the requested dir if it does not exist and set exec.Prepare.Dir = dir
+// WithDir - Option that will create the requested dir if it does not exist and set exec.Cmd.Dir = dir
 func WithDir(dir string) *Option {
 	return CmdOption(func(cmd *exec.Cmd) error {
 		if _, err := os.Stat(dir); os.IsNotExist(err) {
@@ -70,31 +70,43 @@ func WithDir(dir string) *Option {
 	})
 }
 
-// WithStdin - option to set exec.Prepare.Stdout
+// WithStdin - option to set exec.Cmd.Stdout
 func WithStdin(reader io.Reader) *Option {
 	return CmdOption(func(cmd *exec.Cmd) error {
 		cmd.Stdin = reader
 		return nil
 	})
 }
 
-// WithStdout - option to set exec.Prepare.Stdout
+// WithStdout - option to provide a writer to receive exec.Cmd.Stdout
+//              if multiple WithStdout options are received, they are combined
+//              with an io.Multiwriter
 func WithStdout(writer io.Writer) *Option {
 	return CmdOption(func(cmd *exec.Cmd) error {
-		cmd.Stdout = writer
+		if cmd.Stdout == nil {
+			cmd.Stdout = writer
+			return nil
+		}
+		cmd.Stdout = io.MultiWriter(cmd.Stdout, writer)
 		return nil
 	})
 }
 
-// WithStderr - option to set exec.Prepare.Stdout
+// WithStderr - option to provide a writer to receive exec.Cmd.Stderr
+//              if multiple WithStderr options are received, they are combined
+//              with an io.Multiwriter
 func WithStderr(writer io.Writer) *Option {
 	return CmdOption(func(cmd *exec.Cmd) error {
-		cmd.Stderr = writer
+		if cmd.Stderr == nil {
+			cmd.Stderr = writer
+			return nil
+		}
+		cmd.Stderr = io.MultiWriter(cmd.Stderr, writer)
 		return nil
 	})
 }
 
-// WithEnvirons - add entries to exec.Prepare.Env as a series of "key=value" strings
+// WithEnvirons - add entries to exec.Cmd.Env as a series of "key=value" strings
 // Example: WithEnvirons("key1=value1","key2=value2",...)
 func WithEnvirons(environs ...string) *Option {
 	var envs []string
@@ -110,7 +122,7 @@ func WithEnvirons(environs ...string) *Option {
 	return WithEnvKV(envs...)
 }
 
-// WithEnvKV - add entries to exec.Prepare as a series key,value pairs in a list of strings
+// WithEnvKV - add entries to exec.Cmd as a series key,value pairs in a list of strings
 // Existing instances of 'key' will be overwritten
 // Example: WithEnvKV(key1,value2,key2,value2...)
 func WithEnvKV(envs ...string) *Option {
@@ -133,7 +145,7 @@ func WithEnvKV(envs ...string) *Option {
 	})
 }
 
-// WithEnvMap - add entries to exec.Prepare from envMap
+// WithEnvMap - add entries to exec.Cmd from envMap
 // Existing instances of 'key' will be overwritten
 // Example: WithEnvKV(map[string]string{key1:value1,key2:value2})
 func WithEnvMap(envMap map[string]string) *Option {