✨ [subprocess] Add Output to return process output (#329)

<!--
Copyright (C) 2020-2022 Arm Limited or its affiliates and Contributors.
All rights reserved.
SPDX-License-Identifier: Apache-2.0
-->
### Description
- process stdOutput and stdErr are merged and returned by `Output()`



### Test Coverage

<!--
Please put an `x` in the correct box e.g. `[x]` to indicate the testing
coverage of this change.
-->

- [x]  This change is covered by existing or additional automated tests.
- [ ] Manual testing has been performed (and evidence provided) as
automated testing was not feasible.
- [ ] Additional tests are not required for this change (e.g.
documentation update).

Author: acabarbaye

changes/20231010192716.feature

@@ -0,0 +1 @@
+:sparkles: `[logs]` Added a `PlainStringLogger` to store only logged messages without prefixes or flags

changes/20231010195032.feature

@@ -0,0 +1 @@
+:sparkles: `[logs]` Added a `CombinedLoggers` to log into multiple loggers

changes/20231010200309.feature

@@ -0,0 +1 @@
+:sparkles: `[subprocess]` Added `Output` to store the output of a process into a string

utils/logs/multiple_logger.go

@@ -99,6 +99,17 @@ func (c *MultipleLogger) AppendLogger(l ...logr.Logger) error {
 }
 
 func (c *MultipleLogger) Append(l ...Loggers) error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.loggers = append(c.loggers, l...)
+	return nil
+}
+
+type MultipleLoggerWithLoggerSource struct {
+	MultipleLogger
+}
+
+func (c *MultipleLoggerWithLoggerSource) Append(l ...Loggers) error {
 	c.mu.Lock()
 	defer c.mu.Unlock()
 	c.loggers = append(c.loggers, l...)
@@ -107,24 +118,35 @@ func (c *MultipleLogger) Append(l ...Loggers) error {
 
 // NewMultipleLoggers returns a logger which abstracts and internally manages a list of loggers.
 // if no default loggers are provided, the logger will be set to print to the standard output.
-func NewMultipleLoggers(loggerSource string, defaultLoggers ...Loggers) (l IMultipleLoggers, err error) {
+func NewMultipleLoggers(loggerSource string, loggersList ...Loggers) (l IMultipleLoggers, err error) {
 	if loggerSource == "" {
 		err = commonerrors.ErrNoLoggerSource
 		return
 	}
-	list := defaultLoggers
+	list := loggersList
 	if len(list) == 0 {
 		std, err := NewStdLogger(loggerSource)
 		if err != nil {
 			return nil, err
 		}
 		list = []Loggers{std}
 	}
-	l = &MultipleLogger{}
+	l = &MultipleLoggerWithLoggerSource{}
 	err = l.Append(list...)
 	if err != nil {
 		return
 	}
 	err = l.SetLoggerSource(loggerSource)
 	return
 }
+
+// NewCombinedLoggers returns a logger which logs to a list of logger. If list is empty, it will error.
+func NewCombinedLoggers(loggersList ...Loggers) (l IMultipleLoggers, err error) {
+	if len(loggersList) == 0 {
+		err = commonerrors.ErrNoLogger
+		return
+	}
+	l = &MultipleLogger{}
+	err = l.Append(loggersList...)
+	return
+}

utils/logs/multiple_logger_test.go

@@ -10,7 +10,10 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
+	"github.com/ARM-software/golang-utils/utils/commonerrors"
+	"github.com/ARM-software/golang-utils/utils/commonerrors/errortest"
 	"github.com/ARM-software/golang-utils/utils/filesystem"
+	"github.com/ARM-software/golang-utils/utils/logs/logstest"
 )
 
 func TestMultipleLogger(t *testing.T) {
@@ -19,6 +22,18 @@ func TestMultipleLogger(t *testing.T) {
 	testLog(t, loggers)
 }
 
+func TestCombinedLogger(t *testing.T) {
+	_, err := NewCombinedLoggers()
+	errortest.RequireError(t, err, commonerrors.ErrNoLogger)
+	testLogger, err := NewLogrLogger(logstest.NewTestLogger(t), "Test")
+	require.NoError(t, err)
+	nl, err := NewNoopLogger("Test2")
+	require.NoError(t, err)
+	loggers, err := NewCombinedLoggers(testLogger, nl)
+	require.NoError(t, err)
+	testLog(t, loggers)
+}
+
 func TestMultipleLoggers(t *testing.T) {
 	// With default logger
 	loggers, err := NewMultipleLoggers("Test Multiple")

utils/logs/string_logger.go

@@ -62,6 +62,7 @@ func (l *StringLoggers) Close() (err error) {
 }
 
 // NewStringLogger creates a logger to a string builder.
+// All messages (whether they are output or error) are merged together.
 func NewStringLogger(loggerSource string) (loggers *StringLoggers, err error) {
 	loggers = &StringLoggers{
 		LogWriter: StringWriter{},
@@ -73,6 +74,19 @@ func NewStringLogger(loggerSource string) (loggers *StringLoggers, err error) {
 	return
 }
 
+// NewPlainStringLogger creates a logger to a string builder with no extra flag, prefix or tag, just the logged text.
+// All messages (whether they are output or error) are merged together.
+func NewPlainStringLogger() (loggers *StringLoggers, err error) {
+	loggers = &StringLoggers{
+		LogWriter: StringWriter{},
+	}
+	loggers.GenericLoggers = GenericLoggers{
+		Output: log.New(&loggers.LogWriter, "", 0),
+		Error:  log.New(&loggers.LogWriter, "", 0),
+	}
+	return
+}
+
 // CreateStringLogger creates a logger to a string builder.
 //
 // Deprecated: Use NewStringLogger instead

utils/logs/string_logger_test.go

@@ -18,7 +18,19 @@ func TestStringLogger(t *testing.T) {
 	loggers.LogError("Test err")
 	loggers.Log("Test1")
 	contents := loggers.GetLogContent()
-	require.NotZero(t, contents)
+	require.NotEmpty(t, contents)
+	require.True(t, strings.Contains(contents, "Test err"))
+	require.True(t, strings.Contains(contents, "Test1"))
+}
+
+func TestPlainStringLogger(t *testing.T) {
+	loggers, err := NewPlainStringLogger()
+	require.NoError(t, err)
+	testLog(t, loggers)
+	loggers.LogError("Test err")
+	loggers.Log("Test1")
+	contents := loggers.GetLogContent()
+	require.NotEmpty(t, contents)
 	require.True(t, strings.Contains(contents, "Test err"))
 	require.True(t, strings.Contains(contents, "Test1"))
 }

utils/subprocess/command_wrapper_test.go

@@ -21,7 +21,7 @@ import (
 
 func TestCmdRun(t *testing.T) {
 	currentDir, err := os.Getwd()
-	require.Nil(t, err)
+	require.NoError(t, err)
 
 	tests := []struct {
 		name       string
@@ -52,7 +52,7 @@ func TestCmdRun(t *testing.T) {
 			defer goleak.VerifyNone(t)
 			var cmd *command
 			loggers, err := logs.NewLogrLogger(logstest.NewTestLogger(t), "test")
-			require.Nil(t, err)
+			require.NoError(t, err)
 			if platform.IsWindows() {
 				cmd = newCommand(loggers, test.cmdWindows, test.argWindows...)
 			} else {
@@ -62,20 +62,20 @@ func TestCmdRun(t *testing.T) {
 			defer cancel()
 			wrapper := cmd.GetCmd(ctx)
 			err = wrapper.Run()
-			require.Nil(t, err)
+			require.NoError(t, err)
 			err = wrapper.Run()
-			require.NotNil(t, err)
+			require.Error(t, err)
 			cmd.Reset()
 			wrapper = cmd.GetCmd(ctx)
 			err = wrapper.Run()
-			require.Nil(t, err)
+			require.NoError(t, err)
 		})
 	}
 }
 
 func TestCmdStartStop(t *testing.T) {
 	currentDir, err := os.Getwd()
-	require.Nil(t, err)
+	require.NoError(t, err)
 
 	tests := []struct {
 		name       string
@@ -106,7 +106,7 @@ func TestCmdStartStop(t *testing.T) {
 			defer goleak.VerifyNone(t)
 			var cmd *command
 			loggers, err := logs.NewLogrLogger(logstest.NewTestLogger(t), "test")
-			require.Nil(t, err)
+			require.NoError(t, err)
 
 			if platform.IsWindows() {
 				cmd = newCommand(loggers, test.cmdWindows, test.argWindows...)
@@ -117,14 +117,14 @@ func TestCmdStartStop(t *testing.T) {
 			defer cancel()
 			wrapper := cmd.GetCmd(ctx)
 			err = wrapper.Start()
-			require.Nil(t, err)
+			require.NoError(t, err)
 			pid, err := wrapper.Pid()
-			require.Nil(t, err)
+			require.NoError(t, err)
 			assert.NotZero(t, pid)
 			err = wrapper.Start()
-			require.NotNil(t, err)
+			require.Error(t, err)
 			err = wrapper.Stop()
-			require.Nil(t, err)
+			require.NoError(t, err)
 		})
 	}
 }

utils/subprocess/executor.go

@@ -2,7 +2,8 @@
  * Copyright (C) 2020-2022 Arm Limited or its affiliates and Contributors. All rights reserved.
  * SPDX-License-Identifier: Apache-2.0
  */
-// Package subprocess allows you to spawn new processes, retrieve their output/error pipes, and obtain their return codes.
+
+// Package subprocess allows you to spawn new processes, log their output/error and obtain their return codes.
 package subprocess
 
 import (
@@ -32,6 +33,12 @@ func New(ctx context.Context, loggers logs.Loggers, messageOnStart string, messa
 	return
 }
 
+func newPlainSubProcess(ctx context.Context, loggers logs.Loggers, cmd string, args ...string) (p *Subprocess, err error) {
+	p = new(Subprocess)
+	err = p.setup(ctx, loggers, false, "", "", "", cmd, args...)
+	return
+}
+
 // Execute executes a command (i.e. spawns a subprocess)
 func Execute(ctx context.Context, loggers logs.Loggers, messageOnStart string, messageOnSuccess, messageOnFailure string, cmd string, args ...string) (err error) {
 	p, err := New(ctx, loggers, messageOnStart, messageOnSuccess, messageOnFailure, cmd, args...)
@@ -41,8 +48,37 @@ func Execute(ctx context.Context, loggers logs.Loggers, messageOnStart string, m
 	return p.Execute()
 }
 
+// Output executes a command and returns its output (stdOutput and stdErr are merged) as string.
+func Output(ctx context.Context, loggers logs.Loggers, cmd string, args ...string) (output string, err error) {
+	if loggers == nil {
+		err = commonerrors.ErrNoLogger
+		return
+	}
+
+	stringLogger, err := logs.NewPlainStringLogger()
+	if err != nil {
+		return
+	}
+	mLoggers, err := logs.NewCombinedLoggers(loggers, stringLogger)
+	if err != nil {
+		return
+	}
+	p, err := newPlainSubProcess(ctx, mLoggers, cmd, args...)
+	if err != nil {
+		return
+	}
+	err = p.Execute()
+	output = stringLogger.GetLogContent()
+	return
+}
+
 // Setup sets up a sub-process i.e. defines the command cmd and the messages on start, success and failure.
 func (s *Subprocess) Setup(ctx context.Context, loggers logs.Loggers, messageOnStart string, messageOnSuccess, messageOnFailure string, cmd string, args ...string) (err error) {
+	return s.setup(ctx, loggers, true, messageOnStart, messageOnSuccess, messageOnFailure, cmd, args...)
+}
+
+// Setup sets up a sub-process i.e. defines the command cmd and the messages on start, success and failure.
+func (s *Subprocess) setup(ctx context.Context, loggers logs.Loggers, withAdditionalMessages bool, messageOnStart string, messageOnSuccess, messageOnFailure string, cmd string, args ...string) (err error) {
 	if s.IsOn() {
 		err = s.Stop()
 		if err != nil {
@@ -54,7 +90,7 @@ func (s *Subprocess) Setup(ctx context.Context, loggers logs.Loggers, messageOnS
 	s.isRunning.Store(false)
 	s.processMonitoring = newSubprocessMonitoring(ctx)
 	s.command = newCommand(loggers, cmd, args...)
-	s.messsaging = newSubprocessMessaging(loggers, messageOnSuccess, messageOnFailure, messageOnStart, s.command.GetPath())
+	s.messsaging = newSubprocessMessaging(loggers, withAdditionalMessages, messageOnSuccess, messageOnFailure, messageOnStart, s.command.GetPath())
 	s.reset()
 	return s.check()
 }