Improve error handling

.runny.yaml

@@ -3,6 +3,7 @@ env:
   - FOO=fooster
   - BAR=barbara
 commands:
+  # Commands I use when developing runny
   clean:
     run: |
       go clean ./...
@@ -21,12 +22,33 @@ commands:
     run: go generate ./...
   test:
     run: go test ./...
-  test-env:
+
+  # Demo commands to showcase various features of runny
+  demo-env:
     env:
       - FOO=baz
     run: echo $FOO $BAR
-  test-args:
+  demo-args:
     argnames:
       - aa
       - bb
     run: echo $aa is not $bb and $bb is not $aa
+  demo-multiline-command:
+    # Unlike Makefiles, runny makes it simple to run commands that span over multiple lines. Just write them exactly as
+    # you would in a regular script.
+    run: |
+      for x in 1 2 3; do
+        echo $x
+      done
+  demo-broken:
+    run: foo bar
+
+  demo-broken-dependency:
+    needs:
+      - demo-broken
+    run: ls
+
+  demo-unknown-dependency:
+    needs:
+      - unknown
+    run: ls

runny/cmd.go

@@ -1,15 +1,26 @@
 package runny
 
 import (
+	"fmt"
 	"os"
+
+	"github.com/fatih/color"
 )
 
 func Run() {
+	exitWithError := func(err error) {
+		errStr := fmt.Sprintf("%v\n", err)
+		red := color.New(color.FgRed)
+		red.Fprint(os.Stderr, errStr)
+		os.Exit(1)
+	}
+
 	runny, err := readConfig(".runny.yaml")
 	if err != nil {
-		errorColor.Printf("Problem reading config: %v\n", err)
+		exitWithError(err)
 	}
 
+	// Parse command-line options
 	args := os.Args[1:]
 	for len(args) > 0 && args[0][0] == '-' {
 		option := args[0]
@@ -20,19 +31,17 @@ func Run() {
 		case "-v", "--verbose":
 			runny.verbose = true
 		default:
-			errorColor.Printf("Unknown option: %s\n", option)
-			os.Exit(1)
+			exitWithError(fmt.Errorf("unknown option: %s", option))
 		}
 		args = args[1:]
 	}
 
-	// read command line args
+	// Process runny command
 	if len(args) > 0 {
 		name := CommandName(args[0])
 		err := runny.Execute(name, args[1:]...)
 		if err != nil {
-			errorColor.Println(err)
-			os.Exit(1)
+			exitWithError(err)
 		}
 	} else {
 		runny.PrintCommands()

runny/constants.go

@@ -5,4 +5,3 @@ import "github.com/fatih/color"
 var defaultShell = "/bin/bash"
 var primaryColor *color.Color = color.New(color.Bold)
 var secondaryColor *color.Color = color.New(color.FgHiBlack)
-var errorColor *color.Color = color.New(color.FgRed)

runny/model.go

@@ -27,17 +27,16 @@ type Config struct {
 	verbose  bool
 }
 
-func (c *Config) GetShell() Shell {
+func (c *Config) GetShell() (Shell, error) {
 	shellString := c.Shell
 	if len(shellString) == 0 {
 		shellString = defaultShell
 	}
 	shell, err := NewShell(shellString)
 	if err != nil {
-		errorColor.Printf("Error: %v\n", err)
-		os.Exit(1)
+		return nil, err
 	}
-	return shell
+	return shell, nil
 }
 
 func (c *Config) PrintHelp() {
@@ -84,12 +83,14 @@ func (c *Config) PrintCommands() {
 }
 
 func (c *Config) Execute(name CommandName, args ...string) error {
-	shell := c.GetShell()
+	shell, err := c.GetShell()
+	if err != nil {
+		return err
+	}
+
 	command, ok := c.Commands[name]
 	if !ok {
-		errorMsg := fmt.Sprintf("unknown command: %s", name)
-		errorColor.Println(errorMsg)
-		return fmt.Errorf(errorMsg)
+		return fmt.Errorf("unknown command: %s", name)
 	}
 
 	env := append(c.Env, command.Env...)
@@ -111,7 +112,6 @@ func (c *Config) Execute(name CommandName, args ...string) error {
 	for _, name := range command.Needs {
 		err := c.Execute(name)
 		if err != nil {
-			errorColor.Print(err)
 			return err
 		}
 	}

runny/shell.go

@@ -36,9 +36,9 @@ func (b BashShell) Run(command string, extraArgs []string, echoStdout, verbose b
 
 	cmd := exec.Command(b.command, args...)
 	cmd.Env = env
+	cmd.Stderr = os.Stderr
 	if echoStdout {
 		cmd.Stdout = os.Stdout
-		cmd.Stderr = os.Stderr
 	}
 
 	return cmd.Run()