Improve install code to avoid low-level mistakes. (#17779)

* Improve install code to avoid low-level mistakes.

If a user tries to do a re-install in a Gitea database, they gets a warning and double check.
When Gitea runs, it never create empty app.ini automatically.

Also some small (related) refactoring:

* Refactor db.InitEngine related logic make it more clean (especially for the install code)
* Move some i18n strings out from setting.go to make the setting.go can be easily maintained.
* Show errors in CLI code if an incorrect app.ini is used.
* APP_DATA_PATH is created when installing, and checked when starting (no empty directory is created any more).

Author: wxiaoguang

cmd/cmd.go

@@ -16,6 +16,7 @@ import (
 	"syscall"
 
 	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/util"
 
@@ -57,15 +58,17 @@ func confirm() (bool, error) {
 }
 
 func initDB(ctx context.Context) error {
-	return initDBDisableConsole(ctx, false)
-}
-
-func initDBDisableConsole(ctx context.Context, disableConsole bool) error {
-	setting.NewContext()
+	setting.LoadFromExisting()
 	setting.InitDBConfig()
-	setting.NewXORMLogService(disableConsole)
+	setting.NewXORMLogService(false)
+
+	if setting.Database.Type == "" {
+		log.Fatal(`Database settings are missing from the configuration file: %q.
+Ensure you are running in the correct environment or set the correct configuration file with -c.
+If this is the intended configuration file complete the [database] section.`, setting.CustomConf)
+	}
 	if err := db.InitEngine(ctx); err != nil {
-		return fmt.Errorf("models.SetEngine: %v", err)
+		return fmt.Errorf("unable to initialise the database using the configuration in %q. Error: %v", setting.CustomConf, err)
 	}
 	return nil
 }

cmd/convert.go

@@ -35,7 +35,6 @@ func runConvert(ctx *cli.Context) error {
 	log.Info("Custom path: %s", setting.CustomPath)
 	log.Info("Log path: %s", setting.LogRootPath)
 	log.Info("Configuration file: %s", setting.CustomConf)
-	setting.InitDBConfig()
 
 	if !setting.Database.UseMySQL {
 		fmt.Println("This command can only be used with a MySQL database")

cmd/doctor.go

@@ -87,7 +87,7 @@ func runRecreateTable(ctx *cli.Context) error {
 	golog.SetPrefix("")
 	golog.SetOutput(log.NewLoggerAsWriter("INFO", log.GetLogger(log.DEFAULT)))
 
-	setting.NewContext()
+	setting.LoadFromExisting()
 	setting.InitDBConfig()
 
 	setting.EnableXORMLog = ctx.Bool("debug")

cmd/dump.go

@@ -159,7 +159,8 @@ func runDump(ctx *cli.Context) error {
 			fatal("Deleting default logger failed. Can not write to stdout: %v", err)
 		}
 	}
-	setting.NewContext()
+	setting.LoadFromExisting()
+
 	// make sure we are logging to the console no matter what the configuration tells us do to
 	if _, err := setting.Cfg.Section("log").NewKey("MODE", "console"); err != nil {
 		fatal("Setting logging mode to console failed: %v", err)

cmd/dump_repo.go

@@ -88,7 +88,6 @@ func runDumpRepository(ctx *cli.Context) error {
 	log.Info("Custom path: %s", setting.CustomPath)
 	log.Info("Log path: %s", setting.LogRootPath)
 	log.Info("Configuration file: %s", setting.CustomConf)
-	setting.InitDBConfig()
 
 	var (
 		serviceType structs.GitServiceType

cmd/embedded.go

@@ -115,7 +115,7 @@ func initEmbeddedExtractor(c *cli.Context) error {
 	log.DelNamedLogger(log.DEFAULT)
 
 	// Read configuration file
-	setting.NewContext()
+	setting.LoadAllowEmpty()
 
 	pats, err := getPatterns(c.Args())
 	if err != nil {

cmd/mailer.go

@@ -18,7 +18,7 @@ func runSendMail(c *cli.Context) error {
 	ctx, cancel := installSignals()
 	defer cancel()
 
-	setting.NewContext()
+	setting.LoadFromExisting()
 
 	if err := argsSet(c, "title"); err != nil {
 		return err

cmd/migrate.go

@@ -36,7 +36,6 @@ func runMigrate(ctx *cli.Context) error {
 	log.Info("Custom path: %s", setting.CustomPath)
 	log.Info("Log path: %s", setting.LogRootPath)
 	log.Info("Configuration file: %s", setting.CustomConf)
-	setting.InitDBConfig()
 
 	if err := db.InitEngineWithMigration(context.Background(), migrations.Migrate); err != nil {
 		log.Fatal("Failed to initialize ORM engine: %v", err)

cmd/migrate_storage.go

@@ -121,7 +121,6 @@ func runMigrateStorage(ctx *cli.Context) error {
 	log.Info("Custom path: %s", setting.CustomPath)
 	log.Info("Log path: %s", setting.LogRootPath)
 	log.Info("Configuration file: %s", setting.CustomConf)
-	setting.InitDBConfig()
 
 	if err := db.InitEngineWithMigration(context.Background(), migrations.Migrate); err != nil {
 		log.Fatal("Failed to initialize ORM engine: %v", err)

cmd/restore_repo.go

@@ -50,7 +50,7 @@ func runRestoreRepository(c *cli.Context) error {
 	ctx, cancel := installSignals()
 	defer cancel()
 
-	setting.NewContext()
+	setting.LoadFromExisting()
 
 	statusCode, errStr := private.RestoreRepo(
 		ctx,