feat: canonical flow directory with sync engine (files are source of truth)

backend/app/flows/api.py

@@ -4,6 +4,7 @@ from __future__ import annotations
 
 import json
 from collections.abc import AsyncIterator, Iterator
+from pathlib import Path
 from uuid import UUID
 
 import httpx
@@ -16,6 +17,7 @@ from app.settings import settings
 
 from . import runner, store
 from .deploy import import_from_langflow
+from .sync import lfx_id_for, sync_from_directory
 from .langflow_client import (
     LangflowClient,
     LangflowError,
@@ -44,6 +46,7 @@ from .schemas import (
     FlowVersionRead,
     RunRead,
     RunRequest,
+    SyncReport,
 )
 
 flows_router = APIRouter(prefix="/api/flows", tags=["flows"])
@@ -70,6 +73,7 @@ def _read_definition(d) -> FlowDefinitionRead:
         name=d.name,
         description=d.description,
         status=d.status,
+        source_path=d.source_path,
         continuation_flow_id=d.continuation_flow_id,
         created_at=d.created_at,
     )
@@ -134,6 +138,18 @@ def list_flows(session: Session = Depends(get_db)):
     return [_read_definition(d) for d in store.list_definitions(session)]
 
 
+@flows_router.post("/sync", response_model=SyncReport)
+async def sync_flows(
+    session: Session = Depends(get_db),
+    lfx: LfxClient = Depends(get_lfx),
+):
+    """Reconcile backend/flows/*.json into the DB + LFX (add/update/delete)."""
+    try:
+        return await sync_from_directory(session, lfx, Path(settings.flows_dir))
+    except FileNotFoundError as exc:
+        raise HTTPException(status_code=500, detail=str(exc)) from exc
+
+
 @flows_router.get("/{flow_id}", response_model=FlowDefinitionRead)
 def get_flow(flow_id: UUID, session: Session = Depends(get_db)):
     try:
@@ -178,8 +194,12 @@ async def deploy_version(
     except store.NotFoundError as exc:
         raise HTTPException(status_code=404, detail=str(exc)) from exc
     try:
+        # Deterministic LFX id: same (definition, version) always maps to the
+        # same registration, no matter which path deployed it.
         uploaded = await lfx.upload_flow(
-            version.langflow_json, flow_id=str(version.id), replace=True
+            version.langflow_json,
+            flow_id=lfx_id_for(flow_id, version_no),
+            replace=True,
         )
     except LfxInvalidFlow as exc:
         raise HTTPException(status_code=422, detail=str(exc)) from exc