wrap follow and unfollow queries with transactions

outbox/follow.go

@@ -51,7 +51,13 @@ func Follow(ctx context.Context, follower *ap.Actor, followed string, db *sql.DB
 
 	isLocal := strings.HasPrefix(followed, fmt.Sprintf("https://%s/", cfg.Domain))
 
-	if _, err := db.ExecContext(
+	tx, err := db.BeginTx(ctx, nil)
+	if err != nil {
+		return fmt.Errorf("Failed to begin transaction: %w", err)
+	}
+	defer tx.Rollback()
+
+	if _, err := tx.ExecContext(
 		ctx,
 		`INSERT INTO follows (id, follower, followed, accepted) VALUES(?,?,?,?)`,
 		followID,
@@ -62,13 +68,17 @@ func Follow(ctx context.Context, follower *ap.Actor, followed string, db *sql.DB
 		return fmt.Errorf("Failed to insert follow: %w", err)
 	}
 
-	if _, err := db.ExecContext(
+	if _, err := tx.ExecContext(
 		ctx,
 		`INSERT INTO outbox (activity) VALUES(?)`,
 		string(body),
 	); err != nil {
 		return fmt.Errorf("Failed to insert follow activity: %w", err)
 	}
 
+	if err := tx.Commit(); err != nil {
+		return fmt.Errorf("%s failed to follow %s: %w", follower.ID, followed, err)
+	}
+
 	return nil
 }

outbox/unfollow.go

@@ -55,17 +55,27 @@ func Unfollow(ctx context.Context, log *slog.Logger, db *sql.DB, follower *ap.Ac
 		return fmt.Errorf("%s cannot unfollow %s: %w", follower.ID, followed, err)
 	}
 
-	if _, err := db.ExecContext(
+	tx, err := db.BeginTx(ctx, nil)
+	if err != nil {
+		return fmt.Errorf("Failed to begin transaction: %w", err)
+	}
+	defer tx.Rollback()
+
+	if _, err := tx.ExecContext(
 		ctx,
 		`INSERT INTO outbox (activity) VALUES(?)`,
 		string(body),
 	); err != nil {
 		return fmt.Errorf("Failed to insert undo for %s: %w", followID, err)
 	}
 
-	if _, err := db.ExecContext(ctx, `delete from follows where id = ?`, followID); err != nil && !errors.Is(err, sql.ErrNoRows) {
+	if _, err := tx.ExecContext(ctx, `delete from follows where id = ?`, followID); err != nil && !errors.Is(err, sql.ErrNoRows) {
 		return fmt.Errorf("Failed to unfollow %s: %w", followID, err)
 	}
 
+	if err := tx.Commit(); err != nil {
+		return fmt.Errorf("%s failed to unfollow %s: %w", follower.ID, followed, err)
+	}
+
 	return nil
 }