fix(backend): fix uploads for mounted sandbox providers (#2199)

* fix uploads for mounted sandbox providers

* Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

backend/app/gateway/routers/uploads.py

@@ -8,7 +8,7 @@ from fastapi import APIRouter, File, HTTPException, UploadFile
 from pydantic import BaseModel
 
 from deerflow.config.paths import get_paths
-from deerflow.sandbox.sandbox_provider import get_sandbox_provider
+from deerflow.sandbox.sandbox_provider import SandboxProvider, get_sandbox_provider
 from deerflow.uploads.manager import (
     PathTraversalError,
     delete_file_safe,
@@ -53,6 +53,10 @@ def _make_file_sandbox_writable(file_path: os.PathLike[str] | str) -> None:
     os.chmod(file_path, writable_mode, **chmod_kwargs)
 
 
+def _uses_thread_data_mounts(sandbox_provider: SandboxProvider) -> bool:
+    return bool(getattr(sandbox_provider, "uses_thread_data_mounts", False))
+
+
 @router.post("", response_model=UploadResponse)
 async def upload_files(
     thread_id: str,
@@ -70,8 +74,11 @@ async def upload_files(
     uploaded_files = []
 
     sandbox_provider = get_sandbox_provider()
-    sandbox_id = sandbox_provider.acquire(thread_id)
+    sync_to_sandbox = not _uses_thread_data_mounts(sandbox_provider)
-    sandbox = sandbox_provider.get(sandbox_id)
+    sandbox = None
+    if sync_to_sandbox:
+        sandbox_id = sandbox_provider.acquire(thread_id)
+        sandbox = sandbox_provider.get(sandbox_id)
 
     for file in files:
         if not file.filename:
@@ -90,7 +97,7 @@ async def upload_files(
 
             virtual_path = upload_virtual_path(safe_filename)
 
-            if sandbox_id != "local":
+            if sync_to_sandbox and sandbox is not None:
                 _make_file_sandbox_writable(file_path)
                 sandbox.update_file(virtual_path, content)
 
@@ -110,7 +117,7 @@ async def upload_files(
                 if md_path:
                     md_virtual_path = upload_virtual_path(md_path.name)
 
-                    if sandbox_id != "local":
+                    if sync_to_sandbox and sandbox is not None:
                         _make_file_sandbox_writable(md_path)
                         sandbox.update_file(md_virtual_path, md_path.read_bytes())
 

backend/packages/harness/deerflow/community/aio_sandbox/aio_sandbox_provider.py

@@ -119,6 +119,16 @@ class AioSandboxProvider(SandboxProvider):
         if self._config.get("idle_timeout", DEFAULT_IDLE_TIMEOUT) > 0:
             self._start_idle_checker()
 
+    @property
+    def uses_thread_data_mounts(self) -> bool:
+        """Whether thread workspace/uploads/outputs are visible via mounts.
+
+        Local container backends bind-mount the thread data directories, so files
+        written by the gateway are already visible when the sandbox starts.
+        Remote backends may require explicit file sync.
+        """
+        return isinstance(self._backend, LocalContainerBackend)
+
     # ── Factory methods ──────────────────────────────────────────────────
 
     def _create_backend(self) -> SandboxBackend:

backend/packages/harness/deerflow/sandbox/local/local_sandbox_provider.py

@@ -11,6 +11,8 @@ _singleton: LocalSandbox | None = None
 
 
 class LocalSandboxProvider(SandboxProvider):
+    uses_thread_data_mounts = True
+
     def __init__(self):
         """Initialize the local sandbox provider with path mappings."""
         self._path_mappings = self._setup_path_mappings()

backend/packages/harness/deerflow/sandbox/sandbox_provider.py

@@ -8,6 +8,8 @@ from deerflow.sandbox.sandbox import Sandbox
 class SandboxProvider(ABC):
     """Abstract base class for sandbox providers"""
 
+    uses_thread_data_mounts: bool = False
+
     @abstractmethod
     def acquire(self, thread_id: str | None = None) -> str:
         """Acquire a sandbox environment and return its ID.

backend/tests/test_uploads_router.py

@@ -14,6 +14,7 @@ def test_upload_files_writes_thread_storage_and_skips_local_sandbox_sync(tmp_pat
     thread_uploads_dir.mkdir(parents=True)
 
     provider = MagicMock()
+    provider.uses_thread_data_mounts = True
     provider.acquire.return_value = "local"
     sandbox = MagicMock()
     provider.get.return_value = sandbox
@@ -34,11 +35,33 @@ def test_upload_files_writes_thread_storage_and_skips_local_sandbox_sync(tmp_pat
     sandbox.update_file.assert_not_called()
 
 
+def test_upload_files_skips_acquire_when_thread_data_is_mounted(tmp_path):
+    thread_uploads_dir = tmp_path / "uploads"
+    thread_uploads_dir.mkdir(parents=True)
+
+    provider = MagicMock()
+    provider.uses_thread_data_mounts = True
+
+    with (
+        patch.object(uploads, "get_uploads_dir", return_value=thread_uploads_dir),
+        patch.object(uploads, "ensure_uploads_dir", return_value=thread_uploads_dir),
+        patch.object(uploads, "get_sandbox_provider", return_value=provider),
+    ):
+        file = UploadFile(filename="notes.txt", file=BytesIO(b"hello uploads"))
+        result = asyncio.run(uploads.upload_files("thread-mounted", files=[file]))
+
+    assert result.success is True
+    assert (thread_uploads_dir / "notes.txt").read_bytes() == b"hello uploads"
+    provider.acquire.assert_not_called()
+    provider.get.assert_not_called()
+
+
 def test_upload_files_syncs_non_local_sandbox_and_marks_markdown_file(tmp_path):
     thread_uploads_dir = tmp_path / "uploads"
     thread_uploads_dir.mkdir(parents=True)
 
     provider = MagicMock()
+    provider.uses_thread_data_mounts = False
     provider.acquire.return_value = "aio-1"
     sandbox = MagicMock()
     provider.get.return_value = sandbox
@@ -75,6 +98,7 @@ def test_upload_files_makes_non_local_files_sandbox_writable(tmp_path):
     thread_uploads_dir.mkdir(parents=True)
 
     provider = MagicMock()
+    provider.uses_thread_data_mounts = False
     provider.acquire.return_value = "aio-1"
     sandbox = MagicMock()
     provider.get.return_value = sandbox
@@ -104,6 +128,7 @@ def test_upload_files_does_not_adjust_permissions_for_local_sandbox(tmp_path):
     thread_uploads_dir.mkdir(parents=True)
 
     provider = MagicMock()
+    provider.uses_thread_data_mounts = True
     provider.acquire.return_value = "local"
     sandbox = MagicMock()
     provider.get.return_value = sandbox