Simplify sysl command line (#662)

* #619 another approach to fix this issue, its command line will looks like 'sysl codegen @config_file' and config_file has the all of command flags. Actually this approach can simply all commands.

* #619 update test data and test case.

cmd/sysl/sysl.go

@@ -18,6 +18,12 @@ const syslRootMarker = ".sysl"
 // main3 is the real main function. It takes its output streams and command-line
 // arguments as parameters to support testability.
 func main3(args []string, fs afero.Fs, logger *logrus.Logger) error {
+	flags, err := syslutil.PopulateCMDFlagsFromFile(args)
+	if err == nil && len(flags) > 0 {
+		// apply flags in file
+		args = flags
+	}
+
 	syslCmd := kingpin.New("sysl", "System Modelling Language Toolkit")
 	syslCmd.Version(Version)
 	syslCmd.UsageTemplate(kingpin.SeparateOptionalFlagsUsageTemplate)

cmd/sysl/sysl_test.go

@@ -908,3 +908,19 @@ func TestTemplating(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Equal(t, string(expected), string(actual))
 }
+
+func TestMain3(t *testing.T) {
+	logger, _ := test.NewNullLogger()
+	fs := afero.NewOsFs()
+
+	assert.Equal(t, nil, main3([]string{"sysl"}, fs, logger))
+
+	assert.Error(t, main3([]string{"sysl", "codegen"}, fs, logger))
+
+	assert.Error(t, main3([]string{"sysl", "codegen", "@tests/config.txt"}, fs, logger))
+
+	assert.Error(t, main3([]string{"sysl", "codegen", "@tests/config_new.txt"}, fs, logger))
+
+	assert.Error(t, main3([]string{"sysl", "codegen", "--grammar=go.gen.g", "--transform=go.gen.sysl", "model.sysl"},
+		fs, logger))
+}

pkg/syslutil/cmd_config.go

@@ -0,0 +1,40 @@
+package syslutil
+
+import (
+	"fmt"
+	"io/ioutil"
+	"strings"
+)
+
+func ReadCMDFlags(configPath string) ([]string, error) {
+	var flags []string
+	data, ferr := ioutil.ReadFile(configPath)
+	if ferr != nil {
+		return flags, ferr
+	}
+	str := string(data)
+	flags = strings.Fields(strings.TrimSpace(str))
+
+	return flags, nil
+}
+
+func PopulateCMDFlagsFromFile(cmdArgs []string) ([]string, error) {
+	if len(cmdArgs) < 3 {
+		return nil, fmt.Errorf("command arguments are not enough")
+	}
+
+	var fileFlag string
+	for _, flag := range cmdArgs[2:] {
+		if strings.HasPrefix(flag, "@") {
+			fileFlag = flag
+			break
+		}
+	}
+
+	flags, err := ReadCMDFlags(strings.Replace(fileFlag, "@", "", 1))
+	if err != nil {
+		return nil, err
+	}
+
+	return append(cmdArgs[0:2], flags...), err
+}

pkg/syslutil/cmd_config_test.go

@@ -0,0 +1,32 @@
+package syslutil
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestReadCMDFlags(t *testing.T) {
+	t.Parallel()
+	flags, err := ReadCMDFlags("tests/config.txt")
+	assert.Equal(t, nil, err)
+	assert.Equal(t, 4, len(flags))
+	assert.Equal(t, "--grammar=go.gen.g", flags[0])
+	assert.Equal(t, "--transform=go.gen.sysl", flags[1])
+	assert.Equal(t, "model.sysl", flags[2])
+	assert.Equal(t, "--app-name=Test", flags[3])
+}
+
+func TestPopulateCMDFlagsFromFile(t *testing.T) {
+	t.Parallel()
+	cmdArgs := []string{"sysl", "codegen", "@tests/config.txt"}
+	flags, err := PopulateCMDFlagsFromFile(cmdArgs)
+	assert.Equal(t, nil, err)
+	assert.Equal(t, 6, len(flags))
+	assert.Equal(t, "sysl", flags[0])
+	assert.Equal(t, "codegen", flags[1])
+	assert.Equal(t, "--grammar=go.gen.g", flags[2])
+	assert.Equal(t, "--transform=go.gen.sysl", flags[3])
+	assert.Equal(t, "model.sysl", flags[4])
+	assert.Equal(t, "--app-name=Test", flags[5])
+}

pkg/syslutil/tests/config.txt

@@ -0,0 +1 @@
+    --grammar=go.gen.g     --transform=go.gen.sysl          model.sysl          --app-name=Test