add diff mode to init

changelog/unreleased/initdiffmode.md

@@ -0,0 +1,9 @@
+Enhancement: Add `--diff` to the `ocis init` command
+
+We have added a new flag `--diff` to the `ocis init` command to show the diff of the configuration files.
+This is useful to see what has changed in the configuration files when you run the `ocis init` command.
+The diff is stored to the ocispath in the config folder as ocis.config.patch and can be applied using the
+linux `patch` command.
+
+https://github.com/owncloud/ocis/pull/9693
+https://github.com/owncloud/ocis/issues/3645

ocis/pkg/command/init.go

@@ -26,6 +26,12 @@ func InitCommand(cfg *config.Config) *cli.Command {
 				Value:   "ask",
 				Usage:   "Allow insecure oCIS config",
 			},
+			&cli.BoolFlag{
+				Name:    "diff",
+				Aliases: []string{"d"},
+				Usage:   "Show the difference between the current config and the new one",
+				Value:   false,
+			},
 			&cli.BoolFlag{
 				Name:    "force-overwrite",
 				Aliases: []string{"f"},
@@ -57,7 +63,7 @@ func InitCommand(cfg *config.Config) *cli.Command {
 			} else if insecureFlag == strings.ToLower("true") || insecureFlag == strings.ToLower("yes") || insecureFlag == strings.ToLower("y") {
 				insecure = true
 			}
-			err := ocisinit.CreateConfig(insecure, c.Bool("force-overwrite"), c.String("config-path"), c.String("admin-password"))
+			err := ocisinit.CreateConfig(insecure, c.Bool("force-overwrite"), c.Bool("diff"), c.String("config-path"), c.String("admin-password"))
 			if err != nil {
 				log.Fatalf("Could not create config: %s", err)
 			}

ocis/pkg/init/functions.go

@@ -0,0 +1,104 @@
+package init
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"os/exec"
+	"path"
+	"time"
+)
+
+func checkConfigPath(configPath string) error {
+	targetPath := path.Join(configPath, configFilename)
+	if _, err := os.Stat(targetPath); err == nil {
+		return fmt.Errorf("config in %s already exists", targetPath)
+	}
+	return nil
+}
+
+func configExists(configPath string) bool {
+	targetPath := path.Join(configPath, configFilename)
+	if _, err := os.Stat(targetPath); err == nil {
+		return true
+	}
+	return false
+}
+
+func backupOcisConfigFile(configPath string) (string, error) {
+	sourceConfig := path.Join(configPath, configFilename)
+	targetBackupConfig := path.Join(configPath, configFilename+"."+time.Now().Format("2006-01-02-15-04-05")+".backup")
+	source, err := os.Open(sourceConfig)
+	if err != nil {
+		log.Fatalf("Could not read %s (%s)", sourceConfig, err)
+	}
+	defer source.Close()
+	target, err := os.Create(targetBackupConfig)
+	if err != nil {
+		log.Fatalf("Could not generate backup %s (%s)", targetBackupConfig, err)
+	}
+	defer target.Close()
+	_, err = io.Copy(target, source)
+	if err != nil {
+		log.Fatalf("Could not write backup %s (%s)", targetBackupConfig, err)
+	}
+	return targetBackupConfig, nil
+}
+
+// printBanner prints the generated OCIS config banner.
+func printBanner(targetPath, ocisAdminServicePassword, targetBackupConfig string) {
+	fmt.Printf(
+		"\n=========================================\n"+
+			" generated OCIS Config\n"+
+			"=========================================\n"+
+			" configpath : %s\n"+
+			" user       : admin\n"+
+			" password   : %s\n\n",
+		targetPath, ocisAdminServicePassword)
+	if targetBackupConfig != "" {
+		fmt.Printf("\n=========================================\n"+
+			"An older config file has been backuped to\n %s\n\n",
+			targetBackupConfig)
+	}
+}
+
+// writeConfig writes the config to the target path and prints a banner
+func writeConfig(configPath, ocisAdminServicePassword, targetBackupConfig string, yamlOutput []byte) error {
+	targetPath := path.Join(configPath, configFilename)
+	err := os.WriteFile(targetPath, yamlOutput, 0600)
+	if err != nil {
+		return err
+	}
+	printBanner(targetPath, ocisAdminServicePassword, targetBackupConfig)
+	return nil
+}
+
+// writePatch writes the diff to a file
+func writePatch(configPath string, yamlOutput []byte) error {
+	fmt.Println("running in diff mode")
+	tmpFile := path.Join(configPath, "ocis.yaml.tmp")
+	err := os.WriteFile(tmpFile, yamlOutput, 0600)
+	if err != nil {
+		return err
+	}
+	fmt.Println("diff -u " + path.Join(configPath, configFilename) + " " + tmpFile)
+	cmd := exec.Command("diff", "-u", path.Join(configPath, configFilename), tmpFile)
+	stdout, err := cmd.Output()
+	if err == nil {
+		fmt.Println("no changes, your config is up to date")
+		return nil
+	}
+	fmt.Println(string(stdout))
+	err = os.Remove(tmpFile)
+	if err != nil {
+		return err
+	}
+	patchPath := path.Join(configPath, "ocis.config.patch")
+	err = os.WriteFile(patchPath, stdout, 0600)
+	if err != nil {
+		return err
+	}
+	fmt.Printf("diff written to %s\n", patchPath)
+	return nil
+}