backup: Introduce a vanity repository to calculate paths

When we generate a server-side backup, we want to be able to use any
arbitrary replica to then stream the backup directly to object storage.
The problem is that replicas through praefect have rewritten storages
and relative paths. So in order to generate a backup with praefect
paths, we need to have both: the repository used to access on the
filesystem, and the repository used to generate backup paths.

2 files changed, 23 insertions, 9 deletions

diff --git a/internal/backup/backup.go b/internal/backup/backup.go
index 85e9a5055..25495da48 100644
--- a/internal/backup/backup.go
+++ b/internal/backup/backup.go
@@ -198,13 +198,22 @@ func (mgr *Manager) RemoveAllRepositories(ctx context.Context, req *RemoveAllRep
 
 // CreateRequest is the request to create a backup
 type CreateRequest struct {
-	Server      storage.ServerInfo
-	Repository  *gitalypb.Repository
+	// Server contains gitaly server connection information required to call
+	// RPCs in the non-local backup.Manager configuration.
+	Server storage.ServerInfo
+	// Repository is the repository to be backed up.
+	Repository *gitalypb.Repository
+	// VanityRepository is used to determine the backup path.
+	VanityRepository *gitalypb.Repository
+	// Incremental when true will create an increment on the specified full backup.
 	Incremental bool
 }
 
 // Create creates a repository backup.
 func (mgr *Manager) Create(ctx context.Context, req *CreateRequest) error {
+	if req.VanityRepository == nil {
+		req.VanityRepository = req.Repository
+	}
 	repo, err := mgr.repositoryFactory(ctx, req.Repository, req.Server)
 	if err != nil {
 		return fmt.Errorf("manager: %w", err)
@@ -219,12 +228,12 @@ func (mgr *Manager) Create(ctx context.Context, req *CreateRequest) error {
 	var step *Step
 	if req.Incremental {
 		var err error
-		step, err = mgr.locator.BeginIncremental(ctx, req.Repository, mgr.backupID)
+		step, err = mgr.locator.BeginIncremental(ctx, req.VanityRepository, mgr.backupID)
 		if err != nil {
 			return fmt.Errorf("manager: %w", err)
 		}
 	} else {
-		step = mgr.locator.BeginFull(ctx, req.Repository, mgr.backupID)
+		step = mgr.locator.BeginFull(ctx, req.VanityRepository, mgr.backupID)
 	}
 
 	refs, err := repo.ListRefs(ctx)
diff --git a/internal/backup/backup_test.go b/internal/backup/backup_test.go
index 2472da0a5..55631e3ec 100644
--- a/internal/backup/backup_test.go
+++ b/internal/backup/backup_test.go
@@ -159,10 +159,14 @@ func TestManager_Create(t *testing.T) {
 			t.Run(tc.desc, func(t *testing.T) {
 				repo, repoPath := tc.setup(t)
 				backupRoot := testhelper.TempDir(t)
+				vanityRepo := &gitalypb.Repository{
+					RelativePath: "some/path.git",
+					StorageName:  "some_storage",
+				}
 
-				refsPath := joinBackupPath(t, backupRoot, repo, backupID, "001.refs")
-				bundlePath := joinBackupPath(t, backupRoot, repo, backupID, "001.bundle")
-				customHooksPath := joinBackupPath(t, backupRoot, repo, backupID, "001.custom_hooks.tar")
+				refsPath := joinBackupPath(t, backupRoot, vanityRepo, backupID, "001.refs")
+				bundlePath := joinBackupPath(t, backupRoot, vanityRepo, backupID, "001.bundle")
+				customHooksPath := joinBackupPath(t, backupRoot, vanityRepo, backupID, "001.custom_hooks.tar")
 
 				sink := backup.NewFilesystemSink(backupRoot)
 				locator, err := backup.ResolveLocator("pointer", sink)
@@ -170,8 +174,9 @@ func TestManager_Create(t *testing.T) {
 
 				fsBackup := managerTC.setup(t, sink, locator)
 				err = fsBackup.Create(ctx, &backup.CreateRequest{
-					Server:     storage.ServerInfo{Address: cfg.SocketPath, Token: cfg.Auth.Token},
-					Repository: repo,
+					Server:           storage.ServerInfo{Address: cfg.SocketPath, Token: cfg.Auth.Token},
+					Repository:       repo,
+					VanityRepository: vanityRepo,
 				})
 				if tc.err == nil {
 					require.NoError(t, err)