feat: add a dry run flag for validating tasks

src/cmd/run.go

@@ -56,6 +56,9 @@ func (i *listFlag) Set(value string) error {
 	return nil
 }
 
+// dryRun is a flag to only load / validate tasks without running commands
+var dryRun bool
+
 // setRunnerVariables provides a map of set variables from the command line
 var setRunnerVariables map[string]string
 
@@ -140,7 +143,7 @@ var runCmd = &cobra.Command{
 		if len(args) > 0 {
 			taskName = args[0]
 		}
-		if err := runner.Run(tasksFile, taskName, setRunnerVariables); err != nil {
+		if err := runner.Run(tasksFile, taskName, setRunnerVariables, dryRun); err != nil {
 			message.Fatalf(err, "Failed to run action: %s", err.Error())
 		}
 	},
@@ -241,6 +244,7 @@ func init() {
 	rootCmd.AddCommand(runCmd)
 	runFlags := runCmd.Flags()
 	runFlags.StringVarP(&config.TaskFileLocation, "file", "f", config.TasksYAML, lang.CmdRunFlag)
+	runFlags.BoolVar(&dryRun, "dry-run", false, lang.CmdRunDryRun)
 
 	// Setup the --list flag
 	flag.Var(&listTasks, "list", lang.CmdRunList)

src/config/lang/english.go

@@ -51,6 +51,7 @@ const (
 	CmdRunWithVarFlag = "Set the inputs for a task from the command line (KEY=value)"
 	CmdRunList        = "List available tasks in a task file"
 	CmdRunListAll     = "List all available tasks in a task file, including tasks from included files"
+	CmdRunDryRun      = "Validate the task without actually running any commands"
 )
 
 // Common Errors

src/pkg/runner/actions.go

@@ -63,11 +63,10 @@ func (r *Runner) performAction(action types.Action, withs map[string]string, inp
 			return err
 		}
 	} else {
-		err := RunAction(action.BaseAction, r.envFilePath, r.variableConfig)
+		err := RunAction(action.BaseAction, r.envFilePath, r.variableConfig, r.dryRun)
 		if err != nil {
 			return err
 		}
-
 	}
 	return nil
 }
@@ -106,7 +105,7 @@ func getUniqueTaskActions(actions []types.Action) []types.Action {
 }
 
 // RunAction executes a specific action command, either wait or cmd. It handles variable loading environment variables and manages retries and timeouts
-func RunAction[T any](action *types.BaseAction[T], envFilePath string, variableConfig *variables.VariableConfig[T]) error {
+func RunAction[T any](action *types.BaseAction[T], envFilePath string, variableConfig *variables.VariableConfig[T], dryRun bool) error {
 	var (
 		ctx        context.Context
 		cancel     context.CancelFunc
@@ -145,6 +144,19 @@ func RunAction[T any](action *types.BaseAction[T], envFilePath string, variableC
 		action.SetVariables = []variables.Variable[T]{}
 	}
 
+	if action.Description != "" {
+		cmdEscaped = action.Description
+	} else {
+		cmdEscaped = helpers.Truncate(cmd, 60, false)
+	}
+
+	// if this is a dry run, print the command that would run and return
+	if dryRun {
+		message.SLog.Info(fmt.Sprintf("Dry-running %q", cmdEscaped))
+		fmt.Println(cmd)
+		return nil
+	}
+
 	// load the contents of the env file into the Action + the MARU_ARCH
 	if envFilePath != "" {
 		envFilePath := filepath.Join(filepath.Dir(config.TaskFileLocation), envFilePath)
@@ -155,19 +167,13 @@ func RunAction[T any](action *types.BaseAction[T], envFilePath string, variableC
 		action.Env = append(action.Env, strings.Split(string(envFileContents), "\n")...)
 	}
 
-	if action.Description != "" {
-		cmdEscaped = action.Description
-	} else {
-		cmdEscaped = helpers.Truncate(cmd, 60, false)
-	}
-
-	spinner := message.NewProgressSpinner("Running \"%s\"", cmdEscaped)
+	spinner := message.NewProgressSpinner("Running %q", cmdEscaped)
 
 	cfg := GetBaseActionCfg(types.ActionDefaults{}, *action, variableConfig.GetSetVariables())
 
 	if cmd = exec.MutateCommand(cmd, cfg.Shell); err != nil {
 		message.SLog.Debug(err.Error())
-		spinner.Failf("Error mutating command: %s", cmdEscaped)
+		spinner.Failf("Error mutating command: %q", cmdEscaped)
 	}
 
 	// Template dir string

src/pkg/runner/runner.go

@@ -27,10 +27,14 @@ type Runner struct {
 	TaskNameMap    map[string]bool
 	envFilePath    string
 	variableConfig *variables.VariableConfig[variables.ExtraVariableInfo]
+	dryRun         bool
 }
 
 // Run runs a task from tasks file
-func Run(tasksFile types.TasksFile, taskName string, setVariables map[string]string) error {
+func Run(tasksFile types.TasksFile, taskName string, setVariables map[string]string, dryRun bool) error {
+	if dryRun {
+		message.SLog.Info("Dry-run has been set - only printing the commands that would run:")
+	}
 
 	// Populate the variables loaded in the root task file
 	rootVariables := tasksFile.Variables
@@ -61,6 +65,7 @@ func Run(tasksFile types.TasksFile, taskName string, setVariables map[string]str
 		TasksFile:      tasksFile,
 		TaskNameMap:    map[string]bool{},
 		variableConfig: combinedVariableConfig,
+		dryRun:         dryRun,
 	}
 
 	task, err := runner.getTask(taskName)

src/test/e2e/runner_test.go

@@ -423,7 +423,7 @@ func TestTaskRunner(t *testing.T) {
 		t.Parallel()
 		stdOut, stdErr, err := e2e.Maru("run", "true-conditional-nested-nested-nested-task-comp-var-inputs", "--file", "src/test/tasks/conditionals/tasks.yaml")
 		require.NoError(t, err, stdOut, stdErr)
-		require.Contains(t, stdErr, "\"input val2 equals 5 and variable VAL1 equals 5\"")
+		require.Contains(t, stdErr, "Completed \"echo \\\"input val2 equals 5 and variable VAL1 equals 5\\\"\"")
 	})
 	t.Run("test calling a task with nested task calling a task with false conditional comparing variables and inputs", func(t *testing.T) {
 		t.Parallel()
@@ -436,14 +436,14 @@ func TestTaskRunner(t *testing.T) {
 		t.Parallel()
 		stdOut, stdErr, err := e2e.Maru("run", "true-condition-var-as-input-original-syntax-nested-nested-with-comp", "--file", "src/test/tasks/conditionals/tasks.yaml")
 		require.NoError(t, err, stdOut, stdErr)
-		require.Contains(t, stdErr, "\"input val2 equals 5 and variable VAL1 equals 5\"")
+		require.Contains(t, stdErr, "Completed \"echo \\\"input val2 equals 5 and variable VAL1 equals 5\\\"\"")
 	})
 
 	t.Run("test calling a task with nested task calling a task with new style var as input true conditional comparing variables and inputs", func(t *testing.T) {
 		t.Parallel()
 		stdOut, stdErr, err := e2e.Maru("run", "true-condition-var-as-input-new-syntax-nested-nested-with-comp", "--file", "src/test/tasks/conditionals/tasks.yaml")
 		require.NoError(t, err, stdOut, stdErr)
-		require.Contains(t, stdErr, "\"input val2 equals 5 and variable VAL1 equals 5\"")
+		require.Contains(t, stdErr, "Completed \"echo \\\"input val2 equals 5 and variable VAL1 equals 5\\\"\"")
 	})
 
 	t.Run("run successful pattern", func(t *testing.T) {
@@ -461,4 +461,13 @@ func TestTaskRunner(t *testing.T) {
 		require.Error(t, err, stdOut, stdErr)
 		require.Contains(t, stdErr, "\"HELLO\" does not match pattern \"^HELLO$\"")
 	})
+
+	t.Run("dry run", func(t *testing.T) {
+		t.Parallel()
+
+		stdOut, stdErr, err := e2e.Maru("run", "--dry-run", "--file", "src/test/tasks/tasks.yaml", "env-from-file")
+		require.NoError(t, err, stdOut, stdErr)
+		require.Contains(t, stdErr, "Dry-running \"echo $MARU_ARCH\"")
+		require.Contains(t, stdOut, "echo env var from calling task - $SECRET_KEY")
+	})
 }