Added exec.NewCommandExecutor to execute commands with correct interpreter (#1075)

## Changes
Instead of handling command chaining ourselves, we execute passed
commands as-is by storing them, in temp file and passing to correct
interpreter (bash or cmd) based on OS.

Fixes #1065 

## Tests
Added unit tests

bundle/artifacts/whl/infer.go

@@ -33,7 +33,7 @@ func (m *infer) Apply(ctx context.Context, b *bundle.Bundle) error {
 	//   version=datetime.datetime.utcnow().strftime("%Y%m%d.%H%M%S"),
 	// ...
 	//)
-	artifact.BuildCommand = fmt.Sprintf("%s setup.py bdist_wheel", py)
+	artifact.BuildCommand = fmt.Sprintf(`"%s" setup.py bdist_wheel`, py)
 
 	return nil
 }

bundle/config/artifact.go

@@ -1,14 +1,12 @@
 package config
 
 import (
-	"bytes"
 	"context"
 	"fmt"
 	"path"
-	"strings"
 
 	"github.com/databricks/cli/bundle/config/paths"
-	"github.com/databricks/cli/libs/process"
+	"github.com/databricks/cli/libs/exec"
 	"github.com/databricks/databricks-sdk-go/service/compute"
 )
 
@@ -52,20 +50,11 @@ func (a *Artifact) Build(ctx context.Context) ([]byte, error) {
 		return nil, fmt.Errorf("no build property defined")
 	}
 
-	out := make([][]byte, 0)
+	e, err := exec.NewCommandExecutor(a.Path)
-	commands := strings.Split(a.BuildCommand, " && ")
+	if err != nil {
-	for _, command := range commands {
+		return nil, err
-		buildParts := strings.Split(command, " ")
-		var buf bytes.Buffer
-		_, err := process.Background(ctx, buildParts,
-			process.WithCombinedOutput(&buf),
-			process.WithDir(a.Path))
-		if err != nil {
-			return buf.Bytes(), err
-		}
-		out = append(out, buf.Bytes())
 	}
-	return bytes.Join(out, []byte{}), nil
+	return e.Exec(ctx, a.BuildCommand)
 }
 
 func (a *Artifact) NormalisePaths() {

bundle/config/artifacts_test.go

@@ -0,0 +1,18 @@
+package config
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestArtifactBuild(t *testing.T) {
+	artifact := Artifact{
+		BuildCommand: "echo 'Hello from build command'",
+	}
+	res, err := artifact.Build(context.Background())
+	assert.NoError(t, err)
+	assert.NotNil(t, res)
+	assert.Equal(t, "Hello from build command\n", string(res))
+}

bundle/scripts/scripts.go

@@ -5,12 +5,12 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"os/exec"
 	"strings"
 
 	"github.com/databricks/cli/bundle"
 	"github.com/databricks/cli/bundle/config"
 	"github.com/databricks/cli/libs/cmdio"
+	"github.com/databricks/cli/libs/exec"
 	"github.com/databricks/cli/libs/log"
 )
 
@@ -29,7 +29,12 @@ func (m *script) Name() string {
 }
 
 func (m *script) Apply(ctx context.Context, b *bundle.Bundle) error {
-	cmd, out, err := executeHook(ctx, b, m.scriptHook)
+	executor, err := exec.NewCommandExecutor(b.Config.Path)
+	if err != nil {
+		return err
+	}
+
+	cmd, out, err := executeHook(ctx, executor, b, m.scriptHook)
 	if err != nil {
 		return err
 	}
@@ -50,32 +55,18 @@ func (m *script) Apply(ctx context.Context, b *bundle.Bundle) error {
 	return cmd.Wait()
 }
 
-func executeHook(ctx context.Context, b *bundle.Bundle, hook config.ScriptHook) (*exec.Cmd, io.Reader, error) {
+func executeHook(ctx context.Context, executor *exec.Executor, b *bundle.Bundle, hook config.ScriptHook) (exec.Command, io.Reader, error) {
 	command := getCommmand(b, hook)
 	if command == "" {
 		return nil, nil, nil
 	}
 
-	interpreter, err := findInterpreter()
+	cmd, err := executor.StartCommand(ctx, string(command))
 	if err != nil {
 		return nil, nil, err
 	}
 
-	// TODO: switch to process.Background(...)
+	return cmd, io.MultiReader(cmd.Stdout(), cmd.Stderr()), nil
-	cmd := exec.CommandContext(ctx, interpreter, "-c", string(command))
-	cmd.Dir = b.Config.Path
-
-	outPipe, err := cmd.StdoutPipe()
-	if err != nil {
-		return nil, nil, err
-	}
-
-	errPipe, err := cmd.StderrPipe()
-	if err != nil {
-		return nil, nil, err
-	}
-
-	return cmd, io.MultiReader(outPipe, errPipe), cmd.Start()
 }
 
 func getCommmand(b *bundle.Bundle, hook config.ScriptHook) config.Command {
@@ -85,8 +76,3 @@ func getCommmand(b *bundle.Bundle, hook config.ScriptHook) config.Command {
 
 	return b.Config.Experimental.Scripts[hook]
 }
-
-func findInterpreter() (string, error) {
-	// At the moment we just return 'sh' on all platforms and use it to execute scripts
-	return "sh", nil
-}

bundle/scripts/scripts_test.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/databricks/cli/bundle"
 	"github.com/databricks/cli/bundle/config"
+	"github.com/databricks/cli/libs/exec"
 	"github.com/stretchr/testify/require"
 )
 
@@ -21,7 +22,10 @@ func TestExecutesHook(t *testing.T) {
 			},
 		},
 	}
-	_, out, err := executeHook(context.Background(), b, config.ScriptPreBuild)
+
+	executor, err := exec.NewCommandExecutor(b.Config.Path)
+	require.NoError(t, err)
+	_, out, err := executeHook(context.Background(), executor, b, config.ScriptPreBuild)
 	require.NoError(t, err)
 
 	reader := bufio.NewReader(out)

libs/exec/exec.go

@@ -0,0 +1,101 @@
+package exec
+
+import (
+	"context"
+	"io"
+	"os"
+	osexec "os/exec"
+)
+
+type Command interface {
+	// Wait for command to terminate. It must have been previously started.
+	Wait() error
+
+	// StdinPipe returns a pipe that will be connected to the command's standard input when the command starts.
+	Stdout() io.ReadCloser
+
+	// StderrPipe returns a pipe that will be connected to the command's standard error when the command starts.
+	Stderr() io.ReadCloser
+}
+
+type command struct {
+	cmd         *osexec.Cmd
+	execContext *execContext
+	stdout      io.ReadCloser
+	stderr      io.ReadCloser
+}
+
+func (c *command) Wait() error {
+	// After the command has finished (cmd.Wait call), remove the temporary script file
+	defer os.Remove(c.execContext.scriptFile)
+
+	err := c.cmd.Wait()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (c *command) Stdout() io.ReadCloser {
+	return c.stdout
+}
+
+func (c *command) Stderr() io.ReadCloser {
+	return c.stderr
+}
+
+type Executor struct {
+	interpreter interpreter
+	dir         string
+}
+
+func NewCommandExecutor(dir string) (*Executor, error) {
+	interpreter, err := findInterpreter()
+	if err != nil {
+		return nil, err
+	}
+	return &Executor{
+		interpreter: interpreter,
+		dir:         dir,
+	}, nil
+}
+
+func (e *Executor) StartCommand(ctx context.Context, command string) (Command, error) {
+	ec, err := e.interpreter.prepare(command)
+	if err != nil {
+		return nil, err
+	}
+	return e.start(ctx, ec)
+}
+
+func (e *Executor) start(ctx context.Context, ec *execContext) (Command, error) {
+	cmd := osexec.CommandContext(ctx, ec.executable, ec.args...)
+	cmd.Dir = e.dir
+
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		return nil, err
+	}
+
+	stderr, err := cmd.StderrPipe()
+	if err != nil {
+		return nil, err
+	}
+
+	return &command{cmd, ec, stdout, stderr}, cmd.Start()
+}
+
+func (e *Executor) Exec(ctx context.Context, command string) ([]byte, error) {
+	cmd, err := e.StartCommand(ctx, command)
+	if err != nil {
+		return nil, err
+	}
+
+	res, err := io.ReadAll(io.MultiReader(cmd.Stdout(), cmd.Stderr()))
+	if err != nil {
+		return nil, err
+	}
+
+	return res, cmd.Wait()
+}

libs/exec/exec_test.go

@@ -0,0 +1,136 @@
+package exec
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"runtime"
+	"sync"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestExecutorWithSimpleInput(t *testing.T) {
+	executor, err := NewCommandExecutor(".")
+	assert.NoError(t, err)
+	out, err := executor.Exec(context.Background(), "echo 'Hello'")
+	assert.NoError(t, err)
+	assert.NotNil(t, out)
+	assert.Equal(t, "Hello\n", string(out))
+}
+
+func TestExecutorWithComplexInput(t *testing.T) {
+	executor, err := NewCommandExecutor(".")
+	assert.NoError(t, err)
+	out, err := executor.Exec(context.Background(), "echo 'Hello' && echo 'World'")
+	assert.NoError(t, err)
+	assert.NotNil(t, out)
+	assert.Equal(t, "Hello\nWorld\n", string(out))
+}
+
+func TestExecutorWithInvalidCommand(t *testing.T) {
+	executor, err := NewCommandExecutor(".")
+	assert.NoError(t, err)
+	out, err := executor.Exec(context.Background(), "invalid-command")
+	assert.Error(t, err)
+	assert.Contains(t, string(out), "invalid-command: command not found")
+}
+
+func TestExecutorWithInvalidCommandWithWindowsLikePath(t *testing.T) {
+	if runtime.GOOS != "windows" {
+		t.SkipNow()
+	}
+
+	executor, err := NewCommandExecutor(".")
+	assert.NoError(t, err)
+	out, err := executor.Exec(context.Background(), `"C:\Program Files\invalid-command.exe"`)
+	assert.Error(t, err)
+	assert.Contains(t, string(out), "C:\\Program Files\\invalid-command.exe: No such file or directory")
+}
+
+func TestFindBashInterpreterNonWindows(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.SkipNow()
+	}
+
+	interpreter, err := findBashInterpreter()
+	assert.NoError(t, err)
+	assert.NotEmpty(t, interpreter)
+
+	e, err := NewCommandExecutor(".")
+	assert.NoError(t, err)
+	e.interpreter = interpreter
+
+	assert.NoError(t, err)
+	out, err := e.Exec(context.Background(), `echo "Hello from bash"`)
+	assert.NoError(t, err)
+
+	assert.Equal(t, "Hello from bash\n", string(out))
+}
+
+func TestFindCmdInterpreter(t *testing.T) {
+	if runtime.GOOS != "windows" {
+		t.SkipNow()
+	}
+
+	interpreter, err := findCmdInterpreter()
+	assert.NoError(t, err)
+	assert.NotEmpty(t, interpreter)
+
+	e, err := NewCommandExecutor(".")
+	assert.NoError(t, err)
+	e.interpreter = interpreter
+
+	assert.NoError(t, err)
+	out, err := e.Exec(context.Background(), `echo "Hello from cmd"`)
+	assert.NoError(t, err)
+
+	assert.Contains(t, string(out), "Hello from cmd")
+}
+
+func TestExecutorCleanupsTempFiles(t *testing.T) {
+	executor, err := NewCommandExecutor(".")
+	assert.NoError(t, err)
+
+	ec, err := executor.interpreter.prepare("echo 'Hello'")
+	assert.NoError(t, err)
+
+	cmd, err := executor.start(context.Background(), ec)
+	assert.NoError(t, err)
+
+	fileName := ec.args[1]
+	assert.FileExists(t, fileName)
+
+	err = cmd.Wait()
+	assert.NoError(t, err)
+	assert.NoFileExists(t, fileName)
+}
+
+func TestMultipleCommandsRunInParrallel(t *testing.T) {
+	executor, err := NewCommandExecutor(".")
+	assert.NoError(t, err)
+
+	const count = 5
+	var wg sync.WaitGroup
+
+	for i := 0; i < count; i++ {
+		wg.Add(1)
+		cmd, err := executor.StartCommand(context.Background(), fmt.Sprintf("echo 'Hello %d'", i))
+		go func(cmd Command, i int) {
+			defer wg.Done()
+
+			stdout := cmd.Stdout()
+			out, err := io.ReadAll(stdout)
+			assert.NoError(t, err)
+
+			err = cmd.Wait()
+			assert.NoError(t, err)
+
+			assert.Equal(t, fmt.Sprintf("Hello %d\n", i), string(out))
+		}(cmd, i)
+		assert.NoError(t, err)
+	}
+
+	wg.Wait()
+}

libs/exec/interpreter.go

@@ -0,0 +1,123 @@
+package exec
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	osexec "os/exec"
+)
+
+type interpreter interface {
+	prepare(string) (*execContext, error)
+}
+
+type execContext struct {
+	executable string
+	args       []string
+	scriptFile string
+}
+
+type bashInterpreter struct {
+	executable string
+}
+
+func (b *bashInterpreter) prepare(command string) (*execContext, error) {
+	filename, err := createTempScript(command, ".sh")
+	if err != nil {
+		return nil, err
+	}
+
+	return &execContext{
+		executable: b.executable,
+		args:       []string{"-e", filename},
+		scriptFile: filename,
+	}, nil
+}
+
+type cmdInterpreter struct {
+	executable string
+}
+
+func (c *cmdInterpreter) prepare(command string) (*execContext, error) {
+	filename, err := createTempScript(command, ".cmd")
+	if err != nil {
+		return nil, err
+	}
+
+	return &execContext{
+		executable: c.executable,
+		args:       []string{"/D", "/E:ON", "/V:OFF", "/S", "/C", fmt.Sprintf(`CALL %s`, filename)},
+		scriptFile: filename,
+	}, nil
+}
+
+func findInterpreter() (interpreter, error) {
+	interpreter, err := findBashInterpreter()
+	if err != nil {
+		return nil, err
+	}
+
+	if interpreter != nil {
+		return interpreter, nil
+	}
+
+	interpreter, err = findCmdInterpreter()
+	if err != nil {
+		return nil, err
+	}
+
+	if interpreter != nil {
+		return interpreter, nil
+	}
+
+	return nil, errors.New("no interpreter found")
+}
+
+func findBashInterpreter() (interpreter, error) {
+	// Lookup for bash executable first (Linux, MacOS, maybe Windows)
+	out, err := osexec.LookPath("bash")
+	if err != nil && !errors.Is(err, osexec.ErrNotFound) {
+		return nil, err
+	}
+
+	// Bash executable is not found, returning early
+	if out == "" {
+		return nil, nil
+	}
+
+	return &bashInterpreter{executable: out}, nil
+}
+
+func findCmdInterpreter() (interpreter, error) {
+	// Lookup for CMD executable (Windows)
+	out, err := osexec.LookPath("cmd")
+	if err != nil && !errors.Is(err, osexec.ErrNotFound) {
+		return nil, err
+	}
+
+	// CMD executable is not found, returning early
+	if out == "" {
+		return nil, nil
+	}
+
+	return &cmdInterpreter{executable: out}, nil
+}
+
+func createTempScript(command string, extension string) (string, error) {
+	file, err := os.CreateTemp(os.TempDir(), "cli-exec*"+extension)
+	if err != nil {
+		return "", err
+	}
+
+	defer file.Close()
+
+	_, err = io.WriteString(file, command)
+	if err != nil {
+		// Try to remove the file if we failed to write to it
+		os.Remove(file.Name())
+		return "", err
+	}
+
+	return file.Name(), nil
+}