Add support for OS args in in

cmd/in/main.go

@@ -32,7 +32,7 @@ import (
 )
 
 func main() {
-	result, err := dtr.In(os.Stdin)
+	result, err := dtr.In(os.Stdin, os.Args[1:]...)
 	if err != nil {
 		fmt.Fprint(os.Stderr, neat.ContentBox(
 			"Failed to run in",

internal/dtr/common.go

@@ -86,8 +86,14 @@ func LoadConfig(in io.Reader) (*Config, error) {
 	return &config, nil
 }
 
-func command(ctx context.Context, envs map[string]string, run string, out io.Writer) *exec.Cmd {
-	cmd := exec.CommandContext(ctx, defaultCommand, "-c", run)
+func command(ctx context.Context, out io.Writer, envs map[string]string, run string, optArgs ...string) *exec.Cmd {
+	args := []string{"-c", run}
+	if len(optArgs) != 0 {
+		args = append(args, "--")
+		args = append(args, optArgs...)
+	}
+
+	cmd := exec.CommandContext(ctx, defaultCommand, args...)
 	cmd.Stdin = nil
 	cmd.Stdout = out
 	cmd.Stderr = os.Stderr
@@ -100,12 +106,12 @@ func command(ctx context.Context, envs map[string]string, run string, out io.Wri
 	return cmd
 }
 
-func execute(entry Custom) ([]string, error) {
+func execute(entry Custom, args ...string) ([]string, error) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
 	if entry.Before != "" {
-		before := command(ctx, entry.Env, entry.Before, os.Stderr)
+		before := command(ctx, os.Stderr, entry.Env, entry.Before)
 		if err := before.Run(); err != nil {
 			return nil, fmt.Errorf("failure while running before command: %w", err)
 		}
@@ -118,7 +124,7 @@ func execute(entry Custom) ([]string, error) {
 	// For this scenario we would still like to allow no-op In runs
 	// Therefore we can skip command execution if nothing is defined
 	if entry.Run != "" {
-		run := command(ctx, entry.Env, entry.Run, &outStream)
+		run := command(ctx, &outStream, entry.Env, entry.Run, args...)
 		if err := run.Run(); err != nil {
 			return nil, fmt.Errorf("failure while running run command: %w", err)
 		}
@@ -137,11 +143,12 @@ func execute(entry Custom) ([]string, error) {
 func metadata(list []string) []Metadata {
 	var metadata []Metadata
 	for _, entry := range list {
-		split := strings.SplitN(entry, " ", 2)
-		metadata = append(metadata, Metadata{
-			Name:  split[0],
-			Value: split[1]},
-		)
+		if split := strings.SplitN(entry, " ", 2); len(split) == 2 {
+			metadata = append(metadata, Metadata{
+				Name:  split[0],
+				Value: split[1]},
+			)
+		}
 	}
 
 	return metadata

internal/dtr/in.go

@@ -24,13 +24,13 @@ import (
 	"io"
 )
 
-func In(in io.Reader) (InOutResult, error) {
+func In(in io.Reader, args ...string) (InOutResult, error) {
 	config, err := LoadConfig(in)
 	if err != nil {
 		return InOutResult{}, err
 	}
 
-	output, err := execute(config.Source.In)
+	output, err := execute(config.Source.In, args...)
 	if err != nil {
 		return InOutResult{}, err
 	}

internal/dtr/in_test.go

@@ -58,6 +58,25 @@ var _ = Describe("In", func() {
 				{Name: "bar", Value: "foo"},
 			}))
 		})
+
+		It("should have access to the OS arguments", func() {
+			version := Version{"ref": "foobar"}
+			result, err := In(
+				feed(Config{
+					Source: Source{
+						In: Custom{Run: "echo foo $1"},
+					},
+					Version: version,
+				}),
+				"bar",
+			)
+
+			Expect(err).NotTo(HaveOccurred())
+			Expect(result.Version).To(Equal(version))
+			Expect(result.Metadata).To(Equal([]Metadata{
+				{Name: "foo", Value: "bar"},
+			}))
+		})
 	})
 
 	Context("empty/no-op configuration", func() {