transaction: Unify logic to extract optional transaction metadata

The logic to optionally extract transaction metadata from the context is
duplicated across the `internal/gitaly/service/operations` and
`internal/git` packages. Let's deduplicate it and move it into a central
place next to the other metadata-related functions.

3 files changed, 21 insertions, 36 deletions

diff --git a/internal/git/hooks_options.go b/internal/git/hooks_options.go
index 23fe094e7..a091351d1 100644
--- a/internal/git/hooks_options.go
+++ b/internal/git/hooks_options.go
@@ -37,7 +37,7 @@ func (cc *cmdCfg) configureHooks(ctx context.Context, repo *gitalypb.Repository,
 		return errors.New("hooks already configured")
 	}
 
-	transaction, praefect, err := transactionFromContext(ctx)
+	transaction, praefect, err := metadata.TransactionMetadataFromContext(ctx)
 	if err != nil {
 		return err
 	}
@@ -99,20 +99,3 @@ func receivePackHookEnv(ctx context.Context, cc *cmdCfg, cfg config.Cfg, req Rec
 
 	return env, nil
 }
-
-func transactionFromContext(ctx context.Context) (*metadata.Transaction, *metadata.PraefectServer, error) {
-	transaction, err := metadata.TransactionFromContext(ctx)
-	if err != nil {
-		if errors.Is(err, metadata.ErrTransactionNotFound) {
-			return nil, nil, nil
-		}
-		return nil, nil, err
-	}
-
-	praefect, err := metadata.PraefectFromContext(ctx)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	return &transaction, praefect, nil
-}
diff --git a/internal/gitaly/service/operations/update_with_hooks.go b/internal/gitaly/service/operations/update_with_hooks.go
index a723dbb26..7a7537a6a 100644
--- a/internal/gitaly/service/operations/update_with_hooks.go
+++ b/internal/gitaly/service/operations/update_with_hooks.go
@@ -37,7 +37,7 @@ func (s *Server) updateReferenceWithHooks(ctx context.Context, repo *gitalypb.Re
 		return err
 	}
 
-	transaction, praefect, err := transactionFromContext(ctx)
+	transaction, praefect, err := metadata.TransactionMetadataFromContext(ctx)
 	if err != nil {
 		return err
 	}
@@ -102,20 +102,3 @@ func (s *Server) updateReferenceWithHooks(ctx context.Context, repo *gitalypb.Re
 
 	return nil
 }
-
-func transactionFromContext(ctx context.Context) (*metadata.Transaction, *metadata.PraefectServer, error) {
-	transaction, err := metadata.TransactionFromContext(ctx)
-	if err != nil {
-		if err != metadata.ErrTransactionNotFound {
-			return nil, nil, err
-		}
-		return nil, nil, nil
-	}
-
-	praefect, err := metadata.PraefectFromContext(ctx)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	return &transaction, praefect, nil
-}
diff --git a/internal/praefect/metadata/transaction.go b/internal/praefect/metadata/transaction.go
index ca41d1d4b..3663b1183 100644
--- a/internal/praefect/metadata/transaction.go
+++ b/internal/praefect/metadata/transaction.go
@@ -129,3 +129,22 @@ func TransactionFromEnv(envvars []string) (Transaction, error) {
 
 	return transactionFromSerialized(transactionEnv)
 }
+
+// TransactionMetadataFromContext extracts transaction-related metadata from
+// the given context. No error is returned in case no transaction was found.
+func TransactionMetadataFromContext(ctx context.Context) (*Transaction, *PraefectServer, error) {
+	transaction, err := TransactionFromContext(ctx)
+	if err != nil {
+		if err != ErrTransactionNotFound {
+			return nil, nil, err
+		}
+		return nil, nil, nil
+	}
+
+	praefect, err := PraefectFromContext(ctx)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return &transaction, praefect, nil
+}