refactor(sandbox): async init and draft downloads

Reduce startup latency by deferring sandbox setup and downloading draft assets directly with cached presigned URLs.

api/core/sandbox/initializer/__init__.py

@@ -1,9 +1,11 @@
 from .app_assets_initializer import AppAssetsInitializer
+from .draft_app_assets_initializer import DraftAppAssetsInitializer
 from .base import SandboxInitializer
 from .dify_cli_initializer import DifyCliInitializer
 
 __all__ = [
     "AppAssetsInitializer",
+    "DraftAppAssetsInitializer",
     "DifyCliInitializer",
     "SandboxInitializer",
 ]

api/core/sandbox/initializer/app_assets_initializer.py

@@ -22,18 +22,21 @@ class AppAssetsInitializer(SandboxInitializer):
         self._app_id = app_id
         self._assets_id = assets_id
 
-    def initialize(self, sandbox: Sandbox) -> None:
-        vm = sandbox.vm
-        # load app assets
+    def initialize(self, env: Sandbox) -> None:
+        vm = env.vm
+        # Load published app assets and unzip the artifact bundle.
         app_assets = AppAssetService.get_tenant_app_assets(self._tenant_id, self._assets_id)
-        sandbox.attrs.set(AppAssetsAttrs.FILE_TREE, app_assets.asset_tree)
+        env.attrs.set(AppAssetsAttrs.FILE_TREE, app_assets.asset_tree)
 
         zip_key = AssetPaths.build_zip(self._tenant_id, self._app_id, self._assets_id)
         download_url = FilePresignStorage(storage.storage_runner).get_download_url(zip_key)
 
         (
             pipeline(vm)
-            .add(["wget", "-q", download_url, "-O", AppAssets.ZIP_PATH], error_message="Failed to download assets zip")
+            .add(
+                ["wget", "-q", download_url, "-O", AppAssets.ZIP_PATH],
+                error_message="Failed to download assets zip",
+            )
             # unzip with silent error and return 1 if the zip is empty
             # FIXME(Mairuis): should use a more robust way to check if the zip is empty
             .add(

api/core/sandbox/initializer/draft_app_assets_initializer.py

@@ -0,0 +1,44 @@
+import logging
+
+from core.app_assets.constants import AppAssetsAttrs
+from core.sandbox.entities import AppAssets
+from core.sandbox.sandbox import Sandbox
+from core.sandbox.services import AssetDownloadService
+from core.sandbox.services.asset_download_service import AssetDownloadItem
+from core.virtual_environment.__base.helpers import pipeline
+from services.app_asset_service import AppAssetService
+
+from .base import SandboxInitializer
+
+logger = logging.getLogger(__name__)
+
+DRAFT_ASSETS_DOWNLOAD_TIMEOUT = 60 * 10
+
+
+class DraftAppAssetsInitializer(SandboxInitializer):
+    def __init__(self, tenant_id: str, app_id: str, assets_id: str) -> None:
+        self._tenant_id = tenant_id
+        self._app_id = app_id
+        self._assets_id = assets_id
+
+    def initialize(self, env: Sandbox) -> None:
+        vm = env.vm
+        # Draft assets download via presigned URLs to avoid zip build overhead.
+        app_assets = AppAssetService.get_tenant_app_assets(self._tenant_id, self._assets_id)
+        env.attrs.set(AppAssetsAttrs.FILE_TREE, app_assets.asset_tree)
+
+        items = [
+            AssetDownloadItem(path=path, url=url)
+            for path, url in AppAssetService.get_cached_draft_download_urls(app_assets)
+        ]
+        script = AssetDownloadService.build_download_script(items, AppAssets.PATH)
+        pipeline(vm).add(
+            ["sh", "-lc", script],
+            error_message="Failed to download draft assets",
+        ).execute(timeout=DRAFT_ASSETS_DOWNLOAD_TIMEOUT, raise_on_error=True)
+
+        logger.info(
+            "Draft app assets initialized for app_id=%s, assets_id=%s",
+            self._app_id,
+            self._assets_id,
+        )