Add --overwrite option to config init cmd

Currently airshipctl will overwrite an existing config file
by default during config init execution. This patch adds an
appropriate flag to explicitly control whether the user wants
to overwrite an existing file or not.

Change-Id: I9f4756b98e9d1245145809aed203974e99feb662
Signed-off-by: Ruslan Aliev <raliev@mirantis.com>

cmd/config/init.go

@@ -22,34 +22,41 @@ import (
 
 const (
 	initLong = `
-Generate an airshipctl config file and its associated kubeConfig file.
-These files will be written to the $HOME/.airship directory, and will contain
-default configurations.
+Generate an airshipctl config file. This file by default will be written to the $HOME/.airship directory,
+and will contain default configuration. In case if flag --airshipconf provided - the file will be
+written to the specified location instead. If a configuration file already exists at the specified path,
+an error will be thrown; to overwrite it, specify the --overwrite flag.
+`
+	initExample = `
+# Create new airshipctl config file at the default location
+airshipctl config init
 
-NOTE: This will overwrite any existing config files in $HOME/.airship
+# Create new airshipctl config file at the custom location
+airshipctl config init --airshipconf path/to/config
+
+# Create new airshipctl config file at custom location and overwrite it
+airshipctl config init --overwrite --airshipconf path/to/config
 `
 )
 
-// NewInitCommand creates a command for generating default airshipctl config files.
+// NewInitCommand creates a command for generating default airshipctl config file.
 func NewInitCommand() *cobra.Command {
-	// TODO(howell): It'd be nice to have a flag to tell
-	// airshipctl where to store the new files.
-	// TODO(howell): Currently, this command overwrites whatever the user
-	// has in their airship directory. We should remove that functionality
-	// as default and provide and optional --overwrite flag.
+	var overwrite bool
 	cmd := &cobra.Command{
-		Use:   "init",
-		Short: "Generate initial configuration files for airshipctl",
-		Long:  initLong[1:],
+		Use:     "init",
+		Short:   "Generate initial configuration file for airshipctl",
+		Long:    initLong[1:],
+		Example: initExample,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			airshipConfigPath, err := cmd.Flags().GetString("airshipconf")
 			if err != nil {
 				airshipConfigPath = ""
 			}
 
-			return config.CreateConfig(airshipConfigPath)
+			return config.CreateConfig(airshipConfigPath, overwrite)
 		},
 	}
 
+	cmd.Flags().BoolVar(&overwrite, "overwrite", false, "overwrite config file")
 	return cmd
 }

cmd/config/set_management_configuration.go

@@ -92,7 +92,7 @@ func NewSetManagementConfigCommand(cfgFactory config.Factory) *cobra.Command {
 				return nil
 			}
 
-			return cfg.PersistConfig()
+			return cfg.PersistConfig(true)
 		},
 	}
 

cmd/config/testdata/TestConfigGoldenOutput/config-cmd-with-help.golden

@@ -9,7 +9,7 @@ Available Commands:
   get-management-config View a management config or all management configs defined in the airshipctl config
   get-manifest          Get a manifest information from the airshipctl config
   help                  Help about any command
-  init                  Generate initial configuration files for airshipctl
+  init                  Generate initial configuration file for airshipctl
   set-context           Manage contexts
   set-encryption-config Manage encryption configs in airship config
   set-management-config Modify an out-of-band management configuration

cmd/config/testdata/TestConfigInitGoldenOutput/config-init-help.golden

@@ -1,11 +1,23 @@
-Generate an airshipctl config file and its associated kubeConfig file.
-These files will be written to the $HOME/.airship directory, and will contain
-default configurations.
-
-NOTE: This will overwrite any existing config files in $HOME/.airship
+Generate an airshipctl config file. This file by default will be written to the $HOME/.airship directory,
+and will contain default configuration. In case if flag --airshipconf provided - the file will be
+written to the specified location instead. If a configuration file already exists at the specified path,
+an error will be thrown; to overwrite it, specify the --overwrite flag.
 
 Usage:
   init [flags]
 
+Examples:
+
+# Create new airshipctl config file at the default location
+airshipctl config init
+
+# Create new airshipctl config file at the custom location
+airshipctl config init --airshipconf path/to/config
+
+# Create new airshipctl config file at custom location and overwrite it
+airshipctl config init --overwrite --airshipconf path/to/config
+
+
 Flags:
-  -h, --help   help for init
+  -h, --help        help for init
+      --overwrite   overwrite config file

docs/source/cli/airshipctl_config.md

@@ -26,7 +26,7 @@ Manage the airshipctl config file
 * [airshipctl config get-encryption-config](airshipctl_config_get-encryption-config.md)	 - Get an encryption config information from the airshipctl config
 * [airshipctl config get-management-config](airshipctl_config_get-management-config.md)	 - View a management config or all management configs defined in the airshipctl config
 * [airshipctl config get-manifest](airshipctl_config_get-manifest.md)	 - Get a manifest information from the airshipctl config
-* [airshipctl config init](airshipctl_config_init.md)	 - Generate initial configuration files for airshipctl
+* [airshipctl config init](airshipctl_config_init.md)	 - Generate initial configuration file for airshipctl
 * [airshipctl config set-context](airshipctl_config_set-context.md)	 - Manage contexts
 * [airshipctl config set-encryption-config](airshipctl_config_set-encryption-config.md)	 - Manage encryption configs in airship config
 * [airshipctl config set-management-config](airshipctl_config_set-management-config.md)	 - Modify an out-of-band management configuration

docs/source/cli/airshipctl_config_init.md

@@ -1,24 +1,39 @@
 ## airshipctl config init
 
-Generate initial configuration files for airshipctl
+Generate initial configuration file for airshipctl
 
 ### Synopsis
 
-Generate an airshipctl config file and its associated kubeConfig file.
-These files will be written to the $HOME/.airship directory, and will contain
-default configurations.
-
-NOTE: This will overwrite any existing config files in $HOME/.airship
+Generate an airshipctl config file. This file by default will be written to the $HOME/.airship directory,
+and will contain default configuration. In case if flag --airshipconf provided - the file will be
+written to the specified location instead. If a configuration file already exists at the specified path,
+an error will be thrown; to overwrite it, specify the --overwrite flag.
 
 
 ```
 airshipctl config init [flags]
 ```
 
+### Examples
+
+```
+
+# Create new airshipctl config file at the default location
+airshipctl config init
+
+# Create new airshipctl config file at the custom location
+airshipctl config init --airshipconf path/to/config
+
+# Create new airshipctl config file at custom location and overwrite it
+airshipctl config init --overwrite --airshipconf path/to/config
+
+```
+
 ### Options
 
 ```
-  -h, --help   help for init
+  -h, --help        help for init
+      --overwrite   overwrite config file
 ```
 
 ### Options inherited from parent commands

pkg/config/config.go

@@ -94,11 +94,11 @@ func CreateFactory(airshipConfigPath *string) Factory {
 	}
 }
 
-// CreateConfig saves default config to specified paths
-func CreateConfig(airshipConfigPath string) error {
+// CreateConfig saves default config to the specified path
+func CreateConfig(airshipConfigPath string, overwrite bool) error {
 	cfg := NewConfig()
 	cfg.initConfigPath(airshipConfigPath)
-	return cfg.PersistConfig()
+	return cfg.PersistConfig(overwrite)
 }
 
 // initConfigPath - Initializes loadedConfigPath variable for Config object
@@ -177,8 +177,12 @@ func (c *Config) EnsureComplete() error {
 // PersistConfig updates the airshipctl config file to match
 // the current Config object.
 // If file did not previously exist, the file will be created.
-// Otherwise, the file will be overwritten
-func (c *Config) PersistConfig() error {
+// The file will be overwritten if overwrite argument set to true
+func (c *Config) PersistConfig(overwrite bool) error {
+	if _, err := os.Stat(c.loadedConfigPath); err == nil && !overwrite {
+		return ErrConfigFileExists{Path: c.loadedConfigPath}
+	}
+
 	airshipConfigYaml, err := c.ToYaml()
 	if err != nil {
 		return err

pkg/config/config_helper.go

@@ -60,7 +60,7 @@ func RunSetContext(o *ContextOptions, airconfig *Config, writeToStorage bool) (b
 	}
 	// Update configuration file just in time persistence approach
 	if writeToStorage {
-		if err := airconfig.PersistConfig(); err != nil {
+		if err := airconfig.PersistConfig(true); err != nil {
 			// Error that it didnt persist the changes
 			return modified, ErrConfigFailed{}
 		}
@@ -77,7 +77,7 @@ func RunUseContext(desiredContext string, airconfig *Config) error {
 
 	if airconfig.CurrentContext != desiredContext {
 		airconfig.CurrentContext = desiredContext
-		if err := airconfig.PersistConfig(); err != nil {
+		if err := airconfig.PersistConfig(true); err != nil {
 			return err
 		}
 	}
@@ -107,7 +107,7 @@ func RunSetManifest(o *ManifestOptions, airconfig *Config, writeToStorage bool)
 	}
 	// Update configuration file just in time persistence approach
 	if writeToStorage {
-		if err := airconfig.PersistConfig(); err != nil {
+		if err := airconfig.PersistConfig(true); err != nil {
 			// Error that it didnt persist the changes
 			return modified, ErrConfigFailed{}
 		}
@@ -138,7 +138,7 @@ func RunSetEncryptionConfig(o *EncryptionConfigOptions, airconfig *Config, write
 	}
 	// Update configuration file just in time persistence approach
 	if writeToStorage {
-		if err := airconfig.PersistConfig(); err != nil {
+		if err := airconfig.PersistConfig(true); err != nil {
 			// Error that it didnt persist the changes
 			return modified, ErrConfigFailed{}
 		}

pkg/config/config_test.go

@@ -101,11 +101,14 @@ func TestPersistConfig(t *testing.T) {
 
 	conf.SetLoadedConfigPath(conf.LoadedConfigPath() + ".new")
 
-	err := conf.PersistConfig()
+	err := conf.PersistConfig(true)
 	require.NoError(t, err)
 
 	// Check that the files were created
 	assert.FileExists(t, conf.LoadedConfigPath())
+
+	err = conf.PersistConfig(false)
+	require.Error(t, err, config.ErrConfigFileExists{Path: conf.LoadedConfigPath()})
 }
 
 func TestEnsureComplete(t *testing.T) {
@@ -206,7 +209,7 @@ func TestPurge(t *testing.T) {
 	defer cleanup(t)
 
 	// Store it
-	err := conf.PersistConfig()
+	err := conf.PersistConfig(true)
 	assert.NoErrorf(t, err, "Unable to persist configuration expected at %v", conf.LoadedConfigPath())
 
 	// Verify that the file is there

pkg/config/errors.go

@@ -305,3 +305,12 @@ type ErrCheckFile struct {
 func (e ErrCheckFile) Error() string {
 	return fmt.Sprintf("could not read %s data from '%s': %v", e.FlagName, e.Path, e.InternalErr)
 }
+
+// ErrConfigFileExists is returned when there is an existing file at specified location
+type ErrConfigFileExists struct {
+	Path string
+}
+
+func (e ErrConfigFileExists) Error() string {
+	return fmt.Sprintf("could not create default config at %s, file already exists", e.Path)
+}