Merge pull request #25 from tendermint/stderr

CLI Execute Error prints to stderr

.gitignore

@@ -1,2 +1,3 @@
+*.swp
 vendor
 .glide

CHANGELOG.md

@@ -2,6 +2,13 @@
 
 ## Develop-Branch changes (unreleased)
 
+BREAKING CHANGES:
+
+- [run] NewBaseService takes the new logger
+- [cli] RunCaptureWithArgs now captures stderr and stdout
+  - +func RunCaptureWithArgs(cmd Executable, args []string, env map[string]string) (stdout, stderr string, err error)
+  - -func RunCaptureWithArgs(cmd Executable, args []string, env map[string]string) (output string, err error) 
+
 FEATURES:
 
 - [common] Date range parsing from string (ex. "2015-12-31:2017-12-31") 

cli/helper.go

@@ -54,31 +54,40 @@ func RunWithArgs(cmd Executable, args []string, env map[string]string) error {
 	return cmd.Execute()
 }
 
-// RunCaptureWithArgs executes the given command with the specified command line args
-// and environmental variables set. It returns whatever was writen to
-// stdout along with any error returned from cmd.Execute()
-func RunCaptureWithArgs(cmd Executable, args []string, env map[string]string) (output string, err error) {
-	old := os.Stdout // keep backup of the real stdout
-	r, w, _ := os.Pipe()
-	os.Stdout = w
+// RunCaptureWithArgs executes the given command with the specified command
+// line args and environmental variables set. It returns string fields
+// representing output written to stdout and stderr, additionally any error
+// from cmd.Execute() is also returned
+func RunCaptureWithArgs(cmd Executable, args []string, env map[string]string) (stdout, stderr string, err error) {
+	oldout, olderr := os.Stdout, os.Stderr // keep backup of the real stdout
+	rOut, wOut, _ := os.Pipe()
+	rErr, wErr, _ := os.Pipe()
+	os.Stdout, os.Stderr = wOut, wErr
 	defer func() {
-		os.Stdout = old // restoring the real stdout
+		os.Stdout, os.Stderr = oldout, olderr // restoring the real stdout
 	}()
 
-	outC := make(chan string)
 	// copy the output in a separate goroutine so printing can't block indefinitely
-	go func() {
-		var buf bytes.Buffer
-		// io.Copy will end when we call w.Close() below
-		io.Copy(&buf, r)
-		outC <- buf.String()
-	}()
+	copyStd := func(reader *os.File) *(chan string) {
+		stdC := make(chan string)
+		go func() {
+			var buf bytes.Buffer
+			// io.Copy will end when we call reader.Close() below
+			io.Copy(&buf, reader)
+			stdC <- buf.String()
+		}()
+		return &stdC
+	}
+	outC := copyStd(rOut)
+	errC := copyStd(rErr)
 
 	// now run the command
 	err = RunWithArgs(cmd, args, env)
 
 	// and grab the stdout to return
-	w.Close()
-	output = <-outC
-	return output, err
+	wOut.Close()
+	wErr.Close()
+	stdout = <-*outC
+	stderr = <-*errC
+	return stdout, stderr, err
 }

cli/setup.go

@@ -97,9 +97,9 @@ func (e Executor) Execute() error {
 	err := e.Command.Execute()
 	if err != nil {
 		if viper.GetBool(TraceFlag) {
-			fmt.Printf("ERROR: %+v\n", err)
+			fmt.Fprintf(os.Stderr, "ERROR: %+v\n", err)
 		} else {
-			fmt.Println("ERROR:", err.Error())
+			fmt.Fprintf(os.Stderr, "ERROR: %v\n", err)
 		}
 
 		// return error code 1 by default, can override it with a special error type

cli/setup_test.go

@@ -223,9 +223,11 @@ func TestSetupTrace(t *testing.T) {
 
 		viper.Reset()
 		args := append([]string{cmd.Use}, tc.args...)
-		out, err := RunCaptureWithArgs(cmd, args, tc.env)
+		stdout, stderr, err := RunCaptureWithArgs(cmd, args, tc.env)
 		require.NotNil(err, i)
-		msg := strings.Split(out, "\n")
+		require.Equal("", stdout, i)
+		require.NotEqual("", stderr, i)
+		msg := strings.Split(stderr, "\n")
 		desired := fmt.Sprintf("ERROR: %s", tc.expected)
 		assert.Equal(desired, msg[0], i)
 		if tc.long && assert.True(len(msg) > 2, i) {