feat: openai files provider (#3946)

# What does this PR do?
- Adds OpenAI files provider 
- Note that file content retrieval is pretty limited by `purpose`
https://community.openai.com/t/file-uploads-error-why-can-t-i-download-files-with-purpose-user-data/1357013?utm_source=chatgpt.com

## Test Plan
Modify run yaml to use openai files provider:
```
  files:
  - provider_id: openai
    provider_type: remote::openai
    config:
      api_key: ${env.OPENAI_API_KEY:=}
      metadata_store:
        backend: sql_default
        table_name: openai_files_metadata

# Then run files tests
❯ uv run --no-sync ./scripts/integration-tests.sh --stack-config server:ci-tests --inference-mode replay --setup ollama --suite base --pattern test_files
```

src/llama_stack/providers/registry/files.py

@@ -28,4 +28,13 @@ def available_providers() -> list[ProviderSpec]:
             config_class="llama_stack.providers.remote.files.s3.config.S3FilesImplConfig",
             description="AWS S3-based file storage provider for scalable cloud file management with metadata persistence.",
         ),
+        RemoteProviderSpec(
+            api=Api.files,
+            provider_type="remote::openai",
+            adapter_type="openai",
+            pip_packages=["openai"] + sql_store_pip_packages,
+            module="llama_stack.providers.remote.files.openai",
+            config_class="llama_stack.providers.remote.files.openai.config.OpenAIFilesImplConfig",
+            description="OpenAI Files API provider for managing files through OpenAI's native file storage service.",
+        ),
     ]

src/llama_stack/providers/remote/files/openai/__init__.py

@@ -0,0 +1,19 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
+from typing import Any
+
+from llama_stack.core.datatypes import AccessRule, Api
+
+from .config import OpenAIFilesImplConfig
+
+
+async def get_adapter_impl(config: OpenAIFilesImplConfig, deps: dict[Api, Any], policy: list[AccessRule] | None = None):
+    from .files import OpenAIFilesImpl
+
+    impl = OpenAIFilesImpl(config, policy or [])
+    await impl.initialize()
+    return impl

src/llama_stack/providers/remote/files/openai/config.py

@@ -0,0 +1,28 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
+from typing import Any
+
+from pydantic import BaseModel, Field
+
+from llama_stack.core.storage.datatypes import SqlStoreReference
+
+
+class OpenAIFilesImplConfig(BaseModel):
+    """Configuration for OpenAI Files API provider."""
+
+    api_key: str = Field(description="OpenAI API key for authentication")
+    metadata_store: SqlStoreReference = Field(description="SQL store configuration for file metadata")
+
+    @classmethod
+    def sample_run_config(cls, __distro_dir__: str) -> dict[str, Any]:
+        return {
+            "api_key": "${env.OPENAI_API_KEY}",
+            "metadata_store": SqlStoreReference(
+                backend="sql_default",
+                table_name="openai_files_metadata",
+            ).model_dump(exclude_none=True),
+        }

src/llama_stack/providers/remote/files/openai/files.py

@@ -0,0 +1,239 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
+from datetime import UTC, datetime
+from typing import Annotated, Any
+
+from fastapi import Depends, File, Form, Response, UploadFile
+
+from llama_stack.apis.common.errors import ResourceNotFoundError
+from llama_stack.apis.common.responses import Order
+from llama_stack.apis.files import (
+    ExpiresAfter,
+    Files,
+    ListOpenAIFileResponse,
+    OpenAIFileDeleteResponse,
+    OpenAIFileObject,
+    OpenAIFilePurpose,
+)
+from llama_stack.core.datatypes import AccessRule
+from llama_stack.providers.utils.files.form_data import parse_expires_after
+from llama_stack.providers.utils.sqlstore.api import ColumnDefinition, ColumnType
+from llama_stack.providers.utils.sqlstore.authorized_sqlstore import AuthorizedSqlStore
+from llama_stack.providers.utils.sqlstore.sqlstore import sqlstore_impl
+from openai import OpenAI
+
+from .config import OpenAIFilesImplConfig
+
+
+def _make_file_object(
+    *,
+    id: str,
+    filename: str,
+    purpose: str,
+    bytes: int,
+    created_at: int,
+    expires_at: int,
+    **kwargs: Any,
+) -> OpenAIFileObject:
+    """
+    Construct an OpenAIFileObject and normalize expires_at.
+
+    If expires_at is greater than the max we treat it as no-expiration and
+    return None for expires_at.
+    """
+    obj = OpenAIFileObject(
+        id=id,
+        filename=filename,
+        purpose=OpenAIFilePurpose(purpose),
+        bytes=bytes,
+        created_at=created_at,
+        expires_at=expires_at,
+    )
+
+    if obj.expires_at is not None and obj.expires_at > (obj.created_at + ExpiresAfter.MAX):
+        obj.expires_at = None  # type: ignore
+
+    return obj
+
+
+class OpenAIFilesImpl(Files):
+    """OpenAI Files API implementation."""
+
+    def __init__(self, config: OpenAIFilesImplConfig, policy: list[AccessRule]) -> None:
+        self._config = config
+        self.policy = policy
+        self._client: OpenAI | None = None
+        self._sql_store: AuthorizedSqlStore | None = None
+
+    def _now(self) -> int:
+        """Return current UTC timestamp as int seconds."""
+        return int(datetime.now(UTC).timestamp())
+
+    async def _get_file(self, file_id: str, return_expired: bool = False) -> dict[str, Any]:
+        where: dict[str, str | dict] = {"id": file_id}
+        if not return_expired:
+            where["expires_at"] = {">": self._now()}
+        if not (row := await self.sql_store.fetch_one("openai_files", where=where)):
+            raise ResourceNotFoundError(file_id, "File", "files.list()")
+        return row
+
+    async def _delete_file(self, file_id: str) -> None:
+        """Delete a file from OpenAI and the database."""
+        try:
+            self.client.files.delete(file_id)
+        except Exception as e:
+            # If file doesn't exist on OpenAI side, just remove from metadata store
+            if "not found" not in str(e).lower():
+                raise RuntimeError(f"Failed to delete file from OpenAI: {e}") from e
+
+        await self.sql_store.delete("openai_files", where={"id": file_id})
+
+    async def _delete_if_expired(self, file_id: str) -> None:
+        """If the file exists and is expired, delete it."""
+        if row := await self._get_file(file_id, return_expired=True):
+            if (expires_at := row.get("expires_at")) and expires_at <= self._now():
+                await self._delete_file(file_id)
+
+    async def initialize(self) -> None:
+        self._client = OpenAI(api_key=self._config.api_key)
+
+        self._sql_store = AuthorizedSqlStore(sqlstore_impl(self._config.metadata_store), self.policy)
+        await self._sql_store.create_table(
+            "openai_files",
+            {
+                "id": ColumnDefinition(type=ColumnType.STRING, primary_key=True),
+                "filename": ColumnType.STRING,
+                "purpose": ColumnType.STRING,
+                "bytes": ColumnType.INTEGER,
+                "created_at": ColumnType.INTEGER,
+                "expires_at": ColumnType.INTEGER,
+            },
+        )
+
+    async def shutdown(self) -> None:
+        pass
+
+    @property
+    def client(self) -> OpenAI:
+        assert self._client is not None, "Provider not initialized"
+        return self._client
+
+    @property
+    def sql_store(self) -> AuthorizedSqlStore:
+        assert self._sql_store is not None, "Provider not initialized"
+        return self._sql_store
+
+    async def openai_upload_file(
+        self,
+        file: Annotated[UploadFile, File()],
+        purpose: Annotated[OpenAIFilePurpose, Form()],
+        expires_after: Annotated[ExpiresAfter | None, Depends(parse_expires_after)] = None,
+    ) -> OpenAIFileObject:
+        filename = getattr(file, "filename", None) or "uploaded_file"
+        content = await file.read()
+        file_size = len(content)
+
+        created_at = self._now()
+
+        expires_at = created_at + ExpiresAfter.MAX * 42
+        if purpose == OpenAIFilePurpose.BATCH:
+            expires_at = created_at + ExpiresAfter.MAX
+
+        if expires_after is not None:
+            expires_at = created_at + expires_after.seconds
+
+        try:
+            from io import BytesIO
+
+            file_obj = BytesIO(content)
+            file_obj.name = filename
+
+            response = self.client.files.create(
+                file=file_obj,
+                purpose=purpose.value,
+            )
+
+            file_id = response.id
+
+            entry: dict[str, Any] = {
+                "id": file_id,
+                "filename": filename,
+                "purpose": purpose.value,
+                "bytes": file_size,
+                "created_at": created_at,
+                "expires_at": expires_at,
+            }
+
+            await self.sql_store.insert("openai_files", entry)
+
+            return _make_file_object(**entry)
+
+        except Exception as e:
+            raise RuntimeError(f"Failed to upload file to OpenAI: {e}") from e
+
+    async def openai_list_files(
+        self,
+        after: str | None = None,
+        limit: int | None = 10000,
+        order: Order | None = Order.desc,
+        purpose: OpenAIFilePurpose | None = None,
+    ) -> ListOpenAIFileResponse:
+        if not order:
+            order = Order.desc
+
+        where_conditions: dict[str, Any] = {"expires_at": {">": self._now()}}
+        if purpose:
+            where_conditions["purpose"] = purpose.value
+
+        paginated_result = await self.sql_store.fetch_all(
+            table="openai_files",
+            where=where_conditions,
+            order_by=[("created_at", order.value)],
+            cursor=("id", after) if after else None,
+            limit=limit,
+        )
+
+        files = [_make_file_object(**row) for row in paginated_result.data]
+
+        return ListOpenAIFileResponse(
+            data=files,
+            has_more=paginated_result.has_more,
+            first_id=files[0].id if files else "",
+            last_id=files[-1].id if files else "",
+        )
+
+    async def openai_retrieve_file(self, file_id: str) -> OpenAIFileObject:
+        await self._delete_if_expired(file_id)
+        row = await self._get_file(file_id)
+        return _make_file_object(**row)
+
+    async def openai_delete_file(self, file_id: str) -> OpenAIFileDeleteResponse:
+        await self._delete_if_expired(file_id)
+        _ = await self._get_file(file_id)
+        await self._delete_file(file_id)
+        return OpenAIFileDeleteResponse(id=file_id, deleted=True)
+
+    async def openai_retrieve_file_content(self, file_id: str) -> Response:
+        await self._delete_if_expired(file_id)
+
+        row = await self._get_file(file_id)
+
+        try:
+            response = self.client.files.content(file_id)
+            file_content = response.content
+
+        except Exception as e:
+            if "not found" in str(e).lower():
+                await self._delete_file(file_id)
+                raise ResourceNotFoundError(file_id, "File", "files.list()") from e
+            raise RuntimeError(f"Failed to download file from OpenAI: {e}") from e
+
+        return Response(
+            content=file_content,
+            media_type="application/octet-stream",
+            headers={"Content-Disposition": f'attachment; filename="{row["filename"]}"'},
+        )