dry run migration

backend/src/api/routes/migration.py

@@ -14,6 +14,7 @@ from ...core.database import get_db
 from ...models.dashboard import DashboardMetadata, DashboardSelection
 from ...core.superset_client import SupersetClient
 from ...core.logger import belief_scope
+from ...core.migration.dry_run_orchestrator import MigrationDryRunService
 from ...core.mapping_service import IdMappingService
 from ...models.mapping import ResourceMapping
 
@@ -83,6 +84,44 @@ async def execute_migration(
         raise HTTPException(status_code=500, detail=f"Failed to create migration task: {str(e)}")
 # [/DEF:execute_migration:Function]
 
+
+# [DEF:dry_run_migration:Function]
+# @PURPOSE: Build pre-flight diff and risk summary without applying migration.
+# @PRE: Selection and environments are valid.
+# @POST: Returns deterministic JSON diff and risk scoring.
+@router.post("/migration/dry-run", response_model=Dict[str, Any])
+async def dry_run_migration(
+    selection: DashboardSelection,
+    config_manager=Depends(get_config_manager),
+    db: Session = Depends(get_db),
+    _ = Depends(has_permission("plugin:migration", "EXECUTE"))
+):
+    with belief_scope("dry_run_migration"):
+        environments = config_manager.get_environments()
+    env_map = {env.id: env for env in environments}
+    source_env = env_map.get(selection.source_env_id)
+    target_env = env_map.get(selection.target_env_id)
+    if not source_env or not target_env:
+        raise HTTPException(status_code=400, detail="Invalid source or target environment")
+    if selection.source_env_id == selection.target_env_id:
+        raise HTTPException(status_code=400, detail="Source and target environments must be different")
+    if not selection.selected_ids:
+        raise HTTPException(status_code=400, detail="No dashboards selected for dry run")
+
+    service = MigrationDryRunService()
+    source_client = SupersetClient(source_env)
+    target_client = SupersetClient(target_env)
+    try:
+        return service.run(
+            selection=selection,
+            source_client=source_client,
+            target_client=target_client,
+            db=db,
+        )
+    except ValueError as exc:
+        raise HTTPException(status_code=500, detail=str(exc)) from exc
+# [/DEF:dry_run_migration:Function]
+
 # [DEF:get_migration_settings:Function]
 # @PURPOSE: Get current migration Cron string explicitly.
 @router.get("/migration/settings", response_model=Dict[str, str])
@@ -221,4 +260,4 @@ async def trigger_sync_now(
         }
 # [/DEF:trigger_sync_now:Function]
 
-# [/DEF:backend.src.api.routes.migration:Module]
+# [/DEF:backend.src.api.routes.migration:Module]