(GH-15) Add utils.WriteConfig method

This commit adds the `utils.WriteConfig` method, which is called
after each `prm set <PARAM>` command is run. This calls
`viper.WriteConfig` to persist the config on disk.

Also some minor refactoring of `cmd/set`

cmd/set/backend.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 
 	"github.com/puppetlabs/prm/pkg/prm"
+	"github.com/puppetlabs/prm/pkg/utils"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 )
@@ -45,4 +46,5 @@ func (sc *SetCommand) setBackendPreRunE(cmd *cobra.Command, args []string) (err
 
 func (sc *SetCommand) setBackendType(cmd *cobra.Command, args []string) error {
 	return sc.Utils.SetAndWriteConfig(prm.BackendCfgKey, string(SelectedBackend))
+	utils.WriteConfig()
 }

cmd/set/puppet.go

@@ -5,12 +5,11 @@ import (
 
 	"github.com/Masterminds/semver"
 	"github.com/puppetlabs/prm/pkg/prm"
+	"github.com/puppetlabs/prm/pkg/utils"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 )
 
-var PuppetSemVer *semver.Version
-
 func createSetPuppetCommand() *cobra.Command {
 	tmp := &cobra.Command{
 		Use:   "puppet <VERSION>",
@@ -22,7 +21,7 @@ func createSetPuppetCommand() *cobra.Command {
 	return tmp
 }
 
-func setPuppetVersion(cmd *cobra.Command, args []string) (err error) {
+func setPuppetVersion(cmd *cobra.Command, args []string) error {
 	if len(args) > 1 {
 		return fmt.Errorf("only a single Puppet version can be set")
 	}
@@ -31,12 +30,13 @@ func setPuppetVersion(cmd *cobra.Command, args []string) (err error) {
 		return fmt.Errorf("please specify a Puppet version after 'set puppet'")
 	}
 
-	PuppetSemVer, err = semver.NewVersion(args[0])
+	puppetSemVer, err := semver.NewVersion(args[0])
 	if err != nil {
 		return fmt.Errorf("'%s' is not a semantic (x.y.z) Puppet version: %s", args[0], err)
 	}
 
-	viper.Set(prm.PuppetVerCfgKey, PuppetSemVer.String)
+	viper.Set(prm.PuppetVerCfgKey, puppetSemVer.String())
+	utils.WriteConfig()
 
 	return err
 }

cmd/set/set.go

@@ -9,13 +9,11 @@ import (
 
 func CreateSetCommand() *cobra.Command {
 	tmp := &cobra.Command{
-		// TODO: Add Backend as valid arg
-		Use:                   fmt.Sprintf("set %s", prm.PuppetCmdFlag),
+		Use:                   fmt.Sprintf("set <%s|%s> value", prm.BackendCmdFlag, prm.PuppetCmdFlag),
 		Short:                 "Sets the specified configuration to the specified value",
 		Long:                  "Sets the specified configuration to the specified value",
 		DisableFlagsInUseLine: true,
-		// TODO: Add Backend as valid arg		
-		ValidArgs:             []string{prm.PuppetCmdFlag},
+		ValidArgs:             []string{prm.BackendCmdFlag, prm.PuppetCmdFlag},
 		Run: func(cmd *cobra.Command, args []string) {
 			cmd.HelpFunc()(cmd, args)
 		},

pkg/utils/utils.go

@@ -0,0 +1,12 @@
+package utils
+
+import (
+	"github.com/rs/zerolog/log"
+	"github.com/spf13/viper"
+)
+
+func WriteConfig() {
+	if err := viper.WriteConfig(); err != nil {
+		log.Error().Msgf("could not write config to %s: %s", viper.ConfigFileUsed(), err)
+	}
+}