MM-15371: allow config show --json (#10918)

* MM-15371: allow config show --json

Mattermost Cloud will (temporarily?) rely on `mattermost config show` to dump the configuration for an active cluster installation. This adds support for a `--json` flag to dump the config in a format more suitable for programmatic consumption.

* indent config show --json

* ignore coverage lines too

cmd/mattermost/commands/config.go

@@ -82,6 +82,8 @@ func init() {
 	MigrateConfigCmd.Flags().String("to", "", "Config to which to migrate")
 	MigrateConfigCmd.MarkFlagRequired("to")
 
+	ConfigShowCmd.Flags().Bool("json", false, "Output the configuration as JSON.")
+
 	ConfigCmd.AddCommand(
 		ValidateConfigCmd,
 		ConfigSubpathCmd,
@@ -161,9 +163,9 @@ func configGetCmdF(command *cobra.Command, args []string) error {
 }
 
 func configShowCmdF(command *cobra.Command, args []string) error {
-	configStore, err := getConfigStore(command)
+	useJSON, err := command.Flags().GetBool("json")
 	if err != nil {
-		return err
+		return errors.Wrap(err, "failed reading json parameter")
 	}
 
 	err = cobra.NoArgs(command, args)
@@ -171,7 +173,24 @@ func configShowCmdF(command *cobra.Command, args []string) error {
 		return err
 	}
 
-	fmt.Printf("%s", prettyPrintStruct(*configStore.Get()))
+	configStore, err := getConfigStore(command)
+	if err != nil {
+		return err
+	}
+
+	config := *configStore.Get()
+
+	if useJSON {
+		configJSON, err := json.MarshalIndent(config, "", "    ")
+		if err != nil {
+			return errors.Wrap(err, "failed to marshal config as json")
+		}
+
+		fmt.Printf("%s\n", configJSON)
+	} else {
+		fmt.Printf("%s", prettyPrintStruct(config))
+	}
+
 	return nil
 }
 

cmd/mattermost/commands/config_test.go

@@ -4,8 +4,8 @@
 package commands
 
 import (
+	"encoding/json"
 	"fmt"
-	"github.com/mattermost/mattermost-server/config"
 	"io/ioutil"
 	"os"
 	"reflect"
@@ -13,6 +13,8 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/mattermost/mattermost-server/config"
+
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
@@ -335,6 +337,27 @@ func TestConfigShow(t *testing.T) {
 		assert.Contains(t, string(output), "MessageExportSettings")
 		assert.Contains(t, string(output), "AnnouncementSettings")
 	})
+
+	t.Run("successfully dumping config as json", func(t *testing.T) {
+		output, err := th.RunCommandWithOutput(t, "config", "show", "--json")
+		require.Nil(t, err)
+
+		// Filter out the test headers
+		var filteredOutput []string
+		for _, line := range strings.Split(output, "\n") {
+			if strings.HasPrefix(line, "---") || strings.HasPrefix(line, "===") || strings.HasPrefix(line, "PASS") || strings.HasPrefix(line, "coverage:") {
+				continue
+			}
+
+			filteredOutput = append(filteredOutput, line)
+		}
+
+		output = strings.Join(filteredOutput, "")
+
+		var config model.Config
+		err = json.Unmarshal([]byte(output), &config)
+		require.Nil(t, err)
+	})
 }
 
 func TestSetConfig(t *testing.T) {