Add configuration subcommand.

app/cmd/config.go

@@ -0,0 +1,92 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/jlewi/foyle/app/pkg/config"
+	"github.com/pkg/errors"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+	"gopkg.in/yaml.v3"
+)
+
+// NewConfigCmd adds commands to deal with configuration
+func NewConfigCmd() *cobra.Command {
+	cmd := &cobra.Command{
+		Use: "config",
+	}
+
+	cmd.AddCommand(NewGetConfigCmd())
+	cmd.AddCommand(NewSetConfigCmd())
+	return cmd
+}
+
+// NewSetConfigCmd sets a key value pair in the configuration
+func NewSetConfigCmd() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:  "set <name>=<value>",
+		Args: cobra.ExactArgs(1),
+		Run: func(cmd *cobra.Command, args []string) {
+
+			err := func() error {
+				if err := config.InitViper(cmd); err != nil {
+					return err
+				}
+
+				pieces := strings.Split(args[0], "=")
+				if len(pieces) < 2 {
+					return errors.New("Invalid usage; set expects an argument in the form <NAME>=<VALUE>")
+				}
+				cfgName := pieces[0]
+				cfgValue := pieces[1]
+				viper.Set(cfgName, cfgValue)
+				fConfig := config.GetConfig()
+
+				file := viper.ConfigFileUsed()
+				if file == "" {
+					file = config.DefaultConfigFile()
+				}
+				// Persist the configuration
+				return fConfig.Write(file)
+			}()
+
+			if err != nil {
+				fmt.Printf("Failed to set configuration;\n %+v\n", err)
+				os.Exit(1)
+			}
+		},
+	}
+
+	return cmd
+}
+
+// NewGetConfigCmd  prints out the configuration
+func NewGetConfigCmd() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "get",
+		Short: "Dump Foyle configuration as YAML",
+		Run: func(cmd *cobra.Command, args []string) {
+			err := func() error {
+				if err := config.InitViper(cmd); err != nil {
+					return err
+				}
+				fConfig := config.GetConfig()
+
+				if err := yaml.NewEncoder(os.Stdout).Encode(fConfig); err != nil {
+					return err
+				}
+
+				return nil
+			}()
+
+			if err != nil {
+				fmt.Printf("Failed to get configuration;\n %+v\n", err)
+				os.Exit(1)
+			}
+		},
+	}
+
+	return cmd
+}

app/cmd/root.go

@@ -27,5 +27,6 @@ func NewRootCmd() *cobra.Command {
 	rootCmd.AddCommand(NewAssetsCmd())
 	rootCmd.AddCommand(NewVersionCmd(appName, os.Stdout))
 	rootCmd.AddCommand(NewServeCmd())
+	rootCmd.AddCommand(NewConfigCmd())
 	return rootCmd
 }