Added option to disable migrations (#13114)

* Added option to disable migrations

This patch introduces DISABLE_MIGRATIONS parameter in [repository]
section of app.ini (by default set to false). If set to true
it blocks access to repository migration feature.

This mod hides also local repo import option in user editor if
local repo importing or migrations is disabled.

* Alter Example config

DISABLE_MIGRATIONS set to false in example config to
match its default value.

* HTTP error 403 instead of 500 on denied access to migration

* Parameter DISABLE_MIGRATIONS exposed via API

Fixes: 04b04cf854bcb3ed7659442bcf79822bdebe29e9
Author-Change-Id: IB#1105130

modules/context/context.go

@@ -343,6 +343,7 @@ func Contexter() macaron.Handler {
 
 		ctx.Data["EnableSwagger"] = setting.API.EnableSwagger
 		ctx.Data["EnableOpenIDSignIn"] = setting.Service.EnableOpenIDSignIn
+		ctx.Data["DisableMigrations"] = setting.Repository.DisableMigrations
 
 		c.Map(ctx)
 	}

modules/cron/tasks_basic.go

@@ -11,6 +11,7 @@ import (
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/migrations"
 	repository_service "code.gitea.io/gitea/modules/repository"
+	"code.gitea.io/gitea/modules/setting"
 	mirror_service "code.gitea.io/gitea/services/mirror"
 )
 
@@ -115,5 +116,7 @@ func initBasicTasks() {
 	registerArchiveCleanup()
 	registerSyncExternalUsers()
 	registerDeletedBranchesCleanup()
-	registerUpdateMigrationPosterID()
+	if !setting.Repository.DisableMigrations {
+		registerUpdateMigrationPosterID()
+	}
 }

modules/setting/repository.go

@@ -42,6 +42,7 @@ var (
 		DefaultRepoUnits                        []string
 		PrefixArchiveFiles                      bool
 		DisableMirrors                          bool
+		DisableMigrations                       bool
 		DefaultBranch                           string
 		AllowAdoptionOfUnadoptedRepositories    bool
 		AllowDeleteOfUnadoptedRepositories      bool
@@ -152,6 +153,7 @@ var (
 		DefaultRepoUnits:                        []string{},
 		PrefixArchiveFiles:                      true,
 		DisableMirrors:                          false,
+		DisableMigrations:                       false,
 		DefaultBranch:                           "master",
 
 		// Repository editor settings

modules/structs/settings.go

@@ -6,8 +6,9 @@ package structs
 
 // GeneralRepoSettings contains global repository settings exposed by API
 type GeneralRepoSettings struct {
-	MirrorsDisabled bool `json:"mirrors_disabled"`
-	HTTPGitDisabled bool `json:"http_git_disabled"`
+	MirrorsDisabled    bool `json:"mirrors_disabled"`
+	HTTPGitDisabled    bool `json:"http_git_disabled"`
+	MigrationsDisabled bool `json:"migrations_disabled"`
 }
 
 // GeneralUISettings contains global ui settings exposed by API