Feat/config/generate (#136)

Implement config command & generate verb to write default configuration to file or stdout.

cli/cmd/config.go

@@ -0,0 +1,18 @@
+package cmd
+
+import (
+	"github.com/spf13/cobra"
+)
+
+func newConfigCmd() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "config",
+		Short: "Work with Constellation configuration file",
+		Long:  "Generate & manipulate configuration file for Constellation.",
+		Args:  cobra.ExactArgs(0),
+	}
+
+	cmd.AddCommand(newConfigGenerateCmd())
+
+	return cmd
+}

cli/cmd/configgenerate.go

@@ -0,0 +1,55 @@
+package cmd
+
+import (
+	"github.com/edgelesssys/constellation/cli/file"
+	"github.com/edgelesssys/constellation/internal/config"
+	"github.com/edgelesssys/constellation/internal/constants"
+	"github.com/spf13/afero"
+	"github.com/spf13/cobra"
+	"gopkg.in/yaml.v3"
+)
+
+func newConfigGenerateCmd() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "generate",
+		Short: "Generate a default configuration file",
+		Long:  "Generate a default configuration file for your selected cloud provider.",
+		Args:  cobra.ExactArgs(0),
+		RunE:  runConfigGenerate,
+	}
+	cmd.Flags().StringP("file", "f", constants.ConfigFilename, "output file")
+
+	return cmd
+}
+
+type generateFlags struct {
+	file string
+}
+
+func runConfigGenerate(cmd *cobra.Command, args []string) error {
+	fileHandler := file.NewHandler(afero.NewOsFs())
+	return configGenerate(cmd, fileHandler)
+}
+
+func configGenerate(cmd *cobra.Command, fileHandler file.Handler) error {
+	flags, err := parseGenerateFlags(cmd)
+	if err != nil {
+		return err
+	}
+
+	if flags.file == "-" {
+		return yaml.NewEncoder(cmd.OutOrStdout()).Encode(config.Default())
+	}
+
+	return fileHandler.WriteYAML(flags.file, config.Default(), 0o644)
+}
+
+func parseGenerateFlags(cmd *cobra.Command) (generateFlags, error) {
+	file, err := cmd.Flags().GetString("file")
+	if err != nil {
+		return generateFlags{}, err
+	}
+	return generateFlags{
+		file: file,
+	}, nil
+}

cli/cmd/configgenerate_test.go

@@ -0,0 +1,70 @@
+package cmd
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/edgelesssys/constellation/cli/file"
+	"github.com/edgelesssys/constellation/internal/config"
+	"github.com/edgelesssys/constellation/internal/constants"
+	"github.com/spf13/afero"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"gopkg.in/yaml.v3"
+)
+
+func defaultConfigAsYAML(t *testing.T) string {
+	var readBuffer bytes.Buffer
+	require.NoError(t, yaml.NewEncoder(&readBuffer).Encode(config.Default()))
+	return readBuffer.String()
+}
+
+func TestConfigGenerateDefault(t *testing.T) {
+	assert := assert.New(t)
+	require := require.New(t)
+
+	fileHandler := file.NewHandler(afero.NewMemMapFs())
+	cmd := newConfigGenerateCmd()
+
+	require.NoError(configGenerate(cmd, fileHandler))
+
+	readYAML, err := fileHandler.Read(constants.ConfigFilename)
+	assert.NoError(err)
+	assert.Equal(defaultConfigAsYAML(t), string(readYAML))
+}
+
+func TestConfigGenerateDefaultExists(t *testing.T) {
+	require := require.New(t)
+
+	fileHandler := file.NewHandler(afero.NewMemMapFs())
+	require.NoError(fileHandler.Write(constants.ConfigFilename, []byte("foobar"), file.OptNone))
+	cmd := newConfigGenerateCmd()
+
+	require.Error(configGenerate(cmd, fileHandler))
+}
+
+func TestConfigGenerateFileFlagRemoved(t *testing.T) {
+	require := require.New(t)
+
+	fileHandler := file.NewHandler(afero.NewMemMapFs())
+	cmd := newConfigGenerateCmd()
+	cmd.ResetFlags()
+
+	require.Error(configGenerate(cmd, fileHandler))
+}
+
+func TestConfigGenerateStdOut(t *testing.T) {
+	assert := assert.New(t)
+	require := require.New(t)
+
+	fileHandler := file.NewHandler(afero.NewMemMapFs())
+
+	var outBuffer bytes.Buffer
+	cmd := newConfigGenerateCmd()
+	cmd.SetOut(&outBuffer)
+	require.NoError(cmd.Flags().Set("file", "-"))
+
+	require.NoError(configGenerate(cmd, fileHandler))
+
+	assert.Equal(defaultConfigAsYAML(t), outBuffer.String())
+}

cli/cmd/root.go

@@ -38,6 +38,7 @@ func NewRootCmd() *cobra.Command {
 	rootCmd.AddCommand(newRecoverCmd())
 	rootCmd.AddCommand(newTerminateCmd())
 	rootCmd.AddCommand(newVersionCmd())
+	rootCmd.AddCommand(newConfigCmd())
 
 	return rootCmd
 }

internal/constants/constants.go

@@ -26,6 +26,7 @@ const (
 	//
 
 	StateFilename         = "constellation-state.json"
+	ConfigFilename        = "constellation-conf.yaml"
 	AdminConfFilename     = "constellation-admin.conf"
 	MasterSecretFilename  = "constellation-mastersecret.base64"
 	WGQuickConfigFilename = "wg0.conf"