XYZ-37: Advanced Permissions Phase 1 Backend. (#8159)

* XYZ-13: Update Permission and Role structs to new design.

* XYZ-10: Role store.

* XYZ-9/XYZ-44: Roles API endpoints and WebSocket message.

* XYZ-8: Switch server permissions checks to store backed roles.

* XYZ-58: Proper validation of roles where required.

* XYZ-11/XYZ-55: Migration to store backed roles from policy config.

* XYZ-37: Update unit tests to work with database roles.

* XYZ-56: Remove the "guest" role.

* Changes to SetDefaultRolesFromConfig.

* Short-circuit the store if nothing has changed.

* Address first round of review comments.

* Address second round of review comments.

app/app.go

@@ -7,6 +7,7 @@ import (
 	"html/template"
 	"net"
 	"net/http"
+	"reflect"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -25,6 +26,8 @@ import (
 	"github.com/mattermost/mattermost-server/utils"
 )
 
+const ADVANCED_PERMISSIONS_MIGRATION_KEY = "AdvancedPermissionsMigrationComplete"
+
 type App struct {
 	goroutineCount      int32
 	goroutineExitSignal chan struct{}
@@ -62,7 +65,6 @@ type App struct {
 
 	htmlTemplateWatcher *utils.HTMLTemplateWatcher
 	sessionCache        *utils.Cache
-	roles               map[string]*model.Role
 	configListenerId    string
 	licenseListenerId   string
 	disableConfigWatch  bool
@@ -120,7 +122,6 @@ func New(options ...Option) (*App, error) {
 	})
 	app.licenseListenerId = utils.AddLicenseListener(app.configOrLicenseListener)
 	app.regenerateClientConfig()
-	app.SetDefaultRolesBasedOnConfig()
 
 	l4g.Info(utils.T("api.server.new_server.init.info"))
 
@@ -157,7 +158,6 @@ func New(options ...Option) (*App, error) {
 
 func (a *App) configOrLicenseListener() {
 	a.regenerateClientConfig()
-	a.SetDefaultRolesBasedOnConfig()
 }
 
 func (a *App) Shutdown() {
@@ -450,3 +450,57 @@ func (a *App) Handle404(w http.ResponseWriter, r *http.Request) {
 
 	utils.RenderWebError(err, w, r)
 }
+
+// This function migrates the default built in roles from code/config to the database.
+func (a *App) DoAdvancedPermissionsMigration() {
+	// If the migration is already marked as completed, don't do it again.
+	if result := <-a.Srv.Store.System().GetByName(ADVANCED_PERMISSIONS_MIGRATION_KEY); result.Err == nil {
+		return
+	}
+
+	l4g.Info("Migrating roles to database.")
+	roles := model.MakeDefaultRoles()
+	roles = utils.SetRolePermissionsFromConfig(roles, a.Config())
+
+	allSucceeded := true
+
+	for _, role := range roles {
+		if result := <-a.Srv.Store.Role().Save(role); result.Err != nil {
+			// If this failed for reasons other than the role already existing, don't mark the migration as done.
+			if result2 := <-a.Srv.Store.Role().GetByName(role.Name); result2.Err != nil {
+				l4g.Critical("Failed to migrate role to database.")
+				l4g.Critical(result.Err)
+				allSucceeded = false
+			} else {
+				// If the role already existed, check it is the same and update if not.
+				fetchedRole := result.Data.(*model.Role)
+				if !reflect.DeepEqual(fetchedRole.Permissions, role.Permissions) ||
+					fetchedRole.DisplayName != role.DisplayName ||
+					fetchedRole.Description != role.Description ||
+					fetchedRole.SchemeManaged != role.SchemeManaged {
+					role.Id = fetchedRole.Id
+					if result := <-a.Srv.Store.Role().Save(role); result.Err != nil {
+						// Role is not the same, but failed to update.
+						l4g.Critical("Failed to migrate role to database.")
+						l4g.Critical(result.Err)
+						allSucceeded = false
+					}
+				}
+			}
+		}
+	}
+
+	if !allSucceeded {
+		return
+	}
+
+	system := model.System{
+		Name:  ADVANCED_PERMISSIONS_MIGRATION_KEY,
+		Value: "true",
+	}
+
+	if result := <-a.Srv.Store.System().Save(&system); result.Err != nil {
+		l4g.Critical("Failed to mark advanced permissions migration as completed.")
+		l4g.Critical(result.Err)
+	}
+}