feat: Add OpenAI Conversations API (#3429)

# What does this PR do?

Initial implementation for `Conversations` and `ConversationItems` using
`AuthorizedSqlStore` with endpoints to:
- CREATE
- UPDATE
- GET/RETRIEVE/LIST
- DELETE

Set `level=LLAMA_STACK_API_V1`.

NOTE: This does not currently incorporate changes for Responses, that'll
be done in a subsequent PR.

Closes https://github.com/llamastack/llama-stack/issues/3235

## Test Plan
- Unit tests
- Integration tests

Also comparison of [OpenAPI spec for OpenAI
API](https://github.com/openai/openai-openapi/tree/manual_spec)
```bash
oasdiff breaking --fail-on ERR docs/static/llama-stack-spec.yaml https://raw.githubusercontent.com/openai/openai-openapi/refs/heads/manual_spec/openapi.yaml --strip-prefix-base "/v1/openai/v1" \
--match-path '(^/v1/openai/v1/conversations.*|^/conversations.*)'
```

Note I still have some uncertainty about this, I borrowed this info from
@cdoern on https://github.com/llamastack/llama-stack/pull/3514 but need
to spend more time to confirm it's working, at the moment it suggests it
does.

UPDATE on `oasdiff`, I investigated the OpenAI spec further and it looks
like currently the spec does not list Conversations, so that analysis is
useless. Noting for future reference.

---------

Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

llama_stack/apis/conversations/__init__.py

@@ -0,0 +1,31 @@
+# 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 .conversations import (
+    Conversation,
+    ConversationCreateRequest,
+    ConversationDeletedResource,
+    ConversationItem,
+    ConversationItemCreateRequest,
+    ConversationItemDeletedResource,
+    ConversationItemList,
+    Conversations,
+    ConversationUpdateRequest,
+    Metadata,
+)
+
+__all__ = [
+    "Conversation",
+    "ConversationCreateRequest",
+    "ConversationDeletedResource",
+    "ConversationItem",
+    "ConversationItemCreateRequest",
+    "ConversationItemDeletedResource",
+    "ConversationItemList",
+    "Conversations",
+    "ConversationUpdateRequest",
+    "Metadata",
+]

llama_stack/apis/conversations/conversations.py

@@ -0,0 +1,260 @@
+# 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 Annotated, Literal, Protocol, runtime_checkable
+
+from openai import NOT_GIVEN
+from openai._types import NotGiven
+from openai.types.responses.response_includable import ResponseIncludable
+from pydantic import BaseModel, Field
+
+from llama_stack.apis.agents.openai_responses import (
+    OpenAIResponseMessage,
+    OpenAIResponseOutputMessageFileSearchToolCall,
+    OpenAIResponseOutputMessageFunctionToolCall,
+    OpenAIResponseOutputMessageMCPCall,
+    OpenAIResponseOutputMessageMCPListTools,
+    OpenAIResponseOutputMessageWebSearchToolCall,
+)
+from llama_stack.apis.version import LLAMA_STACK_API_V1
+from llama_stack.providers.utils.telemetry.trace_protocol import trace_protocol
+from llama_stack.schema_utils import json_schema_type, register_schema, webmethod
+
+Metadata = dict[str, str]
+
+
+@json_schema_type
+class Conversation(BaseModel):
+    """OpenAI-compatible conversation object."""
+
+    id: str = Field(..., description="The unique ID of the conversation.")
+    object: Literal["conversation"] = Field(
+        default="conversation", description="The object type, which is always conversation."
+    )
+    created_at: int = Field(
+        ..., description="The time at which the conversation was created, measured in seconds since the Unix epoch."
+    )
+    metadata: Metadata | None = Field(
+        default=None,
+        description="Set of 16 key-value pairs that can be attached to an object. This can be useful for storing additional information about the object in a structured format, and querying for objects via API or the dashboard.",
+    )
+    items: list[dict] | None = Field(
+        default=None,
+        description="Initial items to include in the conversation context. You may add up to 20 items at a time.",
+    )
+
+
+@json_schema_type
+class ConversationMessage(BaseModel):
+    """OpenAI-compatible message item for conversations."""
+
+    id: str = Field(..., description="unique identifier for this message")
+    content: list[dict] = Field(..., description="message content")
+    role: str = Field(..., description="message role")
+    status: str = Field(..., description="message status")
+    type: Literal["message"] = "message"
+    object: Literal["message"] = "message"
+
+
+ConversationItem = Annotated[
+    OpenAIResponseMessage
+    | OpenAIResponseOutputMessageFunctionToolCall
+    | OpenAIResponseOutputMessageFileSearchToolCall
+    | OpenAIResponseOutputMessageWebSearchToolCall
+    | OpenAIResponseOutputMessageMCPCall
+    | OpenAIResponseOutputMessageMCPListTools,
+    Field(discriminator="type"),
+]
+register_schema(ConversationItem, name="ConversationItem")
+
+# Using OpenAI types directly caused issues but some notes for reference:
+# Note that ConversationItem is a Annotated Union of the types below:
+# from openai.types.responses import *
+# from openai.types.responses.response_item import *
+# from openai.types.conversations import ConversationItem
+# f = [
+#     ResponseFunctionToolCallItem,
+#     ResponseFunctionToolCallOutputItem,
+#     ResponseFileSearchToolCall,
+#     ResponseFunctionWebSearch,
+#     ImageGenerationCall,
+#     ResponseComputerToolCall,
+#     ResponseComputerToolCallOutputItem,
+#     ResponseReasoningItem,
+#     ResponseCodeInterpreterToolCall,
+#     LocalShellCall,
+#     LocalShellCallOutput,
+#     McpListTools,
+#     McpApprovalRequest,
+#     McpApprovalResponse,
+#     McpCall,
+#     ResponseCustomToolCall,
+#     ResponseCustomToolCallOutput
+# ]
+
+
+@json_schema_type
+class ConversationCreateRequest(BaseModel):
+    """Request body for creating a conversation."""
+
+    items: list[ConversationItem] | None = Field(
+        default=[],
+        description="Initial items to include in the conversation context. You may add up to 20 items at a time.",
+        max_length=20,
+    )
+    metadata: Metadata | None = Field(
+        default={},
+        description="Set of 16 key-value pairs that can be attached to an object. Useful for storing additional information",
+        max_length=16,
+    )
+
+
+@json_schema_type
+class ConversationUpdateRequest(BaseModel):
+    """Request body for updating a conversation."""
+
+    metadata: Metadata = Field(
+        ...,
+        description="Set of 16 key-value pairs that can be attached to an object. This can be useful for storing additional information about the object in a structured format, and querying for objects via API or the dashboard. Keys are strings with a maximum length of 64 characters. Values are strings with a maximum length of 512 characters.",
+    )
+
+
+@json_schema_type
+class ConversationDeletedResource(BaseModel):
+    """Response for deleted conversation."""
+
+    id: str = Field(..., description="The deleted conversation identifier")
+    object: str = Field(default="conversation.deleted", description="Object type")
+    deleted: bool = Field(default=True, description="Whether the object was deleted")
+
+
+@json_schema_type
+class ConversationItemCreateRequest(BaseModel):
+    """Request body for creating conversation items."""
+
+    items: list[ConversationItem] = Field(
+        ...,
+        description="Items to include in the conversation context. You may add up to 20 items at a time.",
+        max_length=20,
+    )
+
+
+@json_schema_type
+class ConversationItemList(BaseModel):
+    """List of conversation items with pagination."""
+
+    object: str = Field(default="list", description="Object type")
+    data: list[ConversationItem] = Field(..., description="List of conversation items")
+    first_id: str | None = Field(default=None, description="The ID of the first item in the list")
+    last_id: str | None = Field(default=None, description="The ID of the last item in the list")
+    has_more: bool = Field(default=False, description="Whether there are more items available")
+
+
+@json_schema_type
+class ConversationItemDeletedResource(BaseModel):
+    """Response for deleted conversation item."""
+
+    id: str = Field(..., description="The deleted item identifier")
+    object: str = Field(default="conversation.item.deleted", description="Object type")
+    deleted: bool = Field(default=True, description="Whether the object was deleted")
+
+
+@runtime_checkable
+@trace_protocol
+class Conversations(Protocol):
+    """Protocol for conversation management operations."""
+
+    @webmethod(route="/conversations", method="POST", level=LLAMA_STACK_API_V1)
+    async def create_conversation(
+        self, items: list[ConversationItem] | None = None, metadata: Metadata | None = None
+    ) -> Conversation:
+        """Create a conversation.
+
+        :param items: Initial items to include in the conversation context.
+        :param metadata: Set of key-value pairs that can be attached to an object.
+        :returns: The created conversation object.
+        """
+        ...
+
+    @webmethod(route="/conversations/{conversation_id}", method="GET", level=LLAMA_STACK_API_V1)
+    async def get_conversation(self, conversation_id: str) -> Conversation:
+        """Get a conversation with the given ID.
+
+        :param conversation_id: The conversation identifier.
+        :returns: The conversation object.
+        """
+        ...
+
+    @webmethod(route="/conversations/{conversation_id}", method="POST", level=LLAMA_STACK_API_V1)
+    async def update_conversation(self, conversation_id: str, metadata: Metadata) -> Conversation:
+        """Update a conversation's metadata with the given ID.
+
+        :param conversation_id: The conversation identifier.
+        :param metadata: Set of key-value pairs that can be attached to an object.
+        :returns: The updated conversation object.
+        """
+        ...
+
+    @webmethod(route="/conversations/{conversation_id}", method="DELETE", level=LLAMA_STACK_API_V1)
+    async def openai_delete_conversation(self, conversation_id: str) -> ConversationDeletedResource:
+        """Delete a conversation with the given ID.
+
+        :param conversation_id: The conversation identifier.
+        :returns: The deleted conversation resource.
+        """
+        ...
+
+    @webmethod(route="/conversations/{conversation_id}/items", method="POST", level=LLAMA_STACK_API_V1)
+    async def add_items(self, conversation_id: str, items: list[ConversationItem]) -> ConversationItemList:
+        """Create items in the conversation.
+
+        :param conversation_id: The conversation identifier.
+        :param items: Items to include in the conversation context.
+        :returns: List of created items.
+        """
+        ...
+
+    @webmethod(route="/conversations/{conversation_id}/items/{item_id}", method="GET", level=LLAMA_STACK_API_V1)
+    async def retrieve(self, conversation_id: str, item_id: str) -> ConversationItem:
+        """Retrieve a conversation item.
+
+        :param conversation_id: The conversation identifier.
+        :param item_id: The item identifier.
+        :returns: The conversation item.
+        """
+        ...
+
+    @webmethod(route="/conversations/{conversation_id}/items", method="GET", level=LLAMA_STACK_API_V1)
+    async def list(
+        self,
+        conversation_id: str,
+        after: str | NotGiven = NOT_GIVEN,
+        include: list[ResponseIncludable] | NotGiven = NOT_GIVEN,
+        limit: int | NotGiven = NOT_GIVEN,
+        order: Literal["asc", "desc"] | NotGiven = NOT_GIVEN,
+    ) -> ConversationItemList:
+        """List items in the conversation.
+
+        :param conversation_id: The conversation identifier.
+        :param after: An item ID to list items after, used in pagination.
+        :param include: Specify additional output data to include in the response.
+        :param limit: A limit on the number of objects to be returned (1-100, default 20).
+        :param order: The order to return items in (asc or desc, default desc).
+        :returns: List of conversation items.
+        """
+        ...
+
+    @webmethod(route="/conversations/{conversation_id}/items/{item_id}", method="DELETE", level=LLAMA_STACK_API_V1)
+    async def openai_delete_conversation_item(
+        self, conversation_id: str, item_id: str
+    ) -> ConversationItemDeletedResource:
+        """Delete a conversation item.
+
+        :param conversation_id: The conversation identifier.
+        :param item_id: The item identifier.
+        :returns: The deleted item resource.
+        """
+        ...

llama_stack/apis/datatypes.py

@@ -129,6 +129,7 @@ class Api(Enum, metaclass=DynamicApiMeta):
     tool_groups = "tool_groups"
     files = "files"
     prompts = "prompts"
+    conversations = "conversations"
 
     # built-in API
     inspect = "inspect"