refactor: Refactor client code to support multi-transport interactions and simplify client interfaces #342

pstephengoogle · 2025-07-24T04:34:55Z

Description

Refactor the client codebase to support automated, configurable, client factory to generate a client based on the agent card details. Adds support for generation of clients based on JSONRPC, gRPC and RESTful interfaces.

gemini-code-assist

Summary of Changes

Hello @pstephengoogle, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly refactors the client and server architecture to support multiple communication protocols (JSONRPC, gRPC, RESTful) seamlessly. It introduces a unified Client interface, a ClientFactory for dynamic client creation based on agent capabilities, and a ClientTaskManager for improved task lifecycle management. Additionally, it adds comprehensive server-side support for RESTful API interactions, ensuring consistency with the gRPC definitions.

Highlights

Multi-Transport Client Architecture: Introduced a new abstract Client interface and implemented concrete clients for JSONRPC, gRPC, and RESTful transports, enabling flexible communication with agents.
Client Factory: Added a ClientFactory to automatically generate appropriate client instances based on agent card details and configurable transport preferences.
Client-Side Task Management: Implemented ClientTaskManager to streamline the handling and tracking of task lifecycle events received from agents.
Server-Side REST API: Introduced new server-side components (RESTApplication, A2ARESTFastAPIApplication, RESTHandler) to support RESTful interactions, mirroring gRPC functionality via protobuf definitions.
Simplified Client Interfaces: Refactored existing client methods to align with the new abstract Client interface, simplifying the overall client-side API.

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gemini-code-assist

Code Review

This pull request introduces a major and well-architected refactoring of the client-side code to support multiple transport protocols (JSON-RPC, gRPC, REST) via a factory pattern. This is a great improvement for modularity and extensibility.

However, the current state of the PR includes several critical issues that must be addressed. There are unresolved git conflict markers in the new REST-related server files, which will prevent the code from running. Additionally, I've found numerous bugs, including NameErrors, AttributeErrors, and TypeErrors in the new client implementations, mostly due to typos, incorrect variable/function names, and misuse of classes.

I've provided detailed comments and suggestions to fix these critical and high-severity issues. Once these are resolved, this will be a solid contribution to the codebase.

src/a2a/client/rest_client.py

src/a2a/client/jsonrpc_client.py

src/a2a/server/request_handlers/rest_handler.py

src/a2a/client/client_task_manager.py

src/a2a/server/apps/rest/rest_app.py

src/a2a/server/request_handlers/rest_handler.py

src/a2a/client/client.py

src/a2a/client/client_task_manager.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

holtskinner · 2025-07-24T15:42:59Z

/gemini review

gemini-code-assist

Code Review

This pull request introduces a major and well-architected refactoring of the client-side code to support multiple transport protocols (JSON-RPC, gRPC, REST) through a factory pattern. The introduction of a common Client abstract base class and a ClientConfig dataclass greatly improves the architecture, making it more modular and extensible. However, the implementation has several areas that need attention, including critical bugs that could lead to runtime errors, missing features, and incomplete work. Addressing these points will help ensure the new client architecture is robust, complete, and ready for use.

src/a2a/client/grpc_client.py

src/a2a/server/request_handlers/rest_handler.py

src/a2a/client/rest_client.py

src/a2a/client/grpc_client.py

src/a2a/client/jsonrpc_client.py

gemini-code-assist · 2025-07-24T15:45:00Z

src/a2a/client/client_factory.py

+from collections.abc import AsyncGenerator
+from typing import Any, TYPE_CHECKING, Callable
+
+import httpx
+
+from httpx_sse import SSEError, aconnect_sse
+from pydantic import ValidationError


This file contains a number of unused imports. To improve code cleanliness and maintainability, it's best to remove them.

Suggested change

from collections.abc import AsyncGenerator

from typing import Any, TYPE_CHECKING, Callable

import httpx

from httpx_sse import SSEError, aconnect_sse

from pydantic import ValidationError

from __future__ import annotations

import logging

from typing import Callable

from a2a.utils import Transports

from a2a.client.client import Client, ClientConfig, Consumer

from a2a.client.jsonrpc_client import NewJsonRpcClient

from a2a.client.grpc_client import NewGrpcClient

from a2a.client.rest_client import NewRestfulClient

from a2a.client.middleware import ClientCallInterceptor

from a2a.types import (

AgentCapabilities,

AgentCard,

)

src/a2a/client/jsonrpc_client.py

src/a2a/client/errors.py

gemini-code-assist · 2025-07-24T15:45:01Z

src/a2a/server/request_handlers/__init__.py

    'JSONRPCHandler',
    'RESTHandler',
    'RequestHandler',
+    'RESTHandler',


RESTHandler is listed twice in the __all__ list. The duplicate should be removed.

src/a2a/client/client_task_manager.py

src/a2a/utils/transports.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

…s and simplify client interfaces (#342) # Description Refactor the client codebase to support automated, configurable, client factory to generate a client based on the agent card details. Adds support for generation of clients based on JSONRPC, gRPC and RESTful interfaces. --------- Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com> Co-authored-by: Holt Skinner <[email protected]> Co-authored-by: Holt Skinner <[email protected]>

pstephengoogle added 4 commits July 18, 2025 04:47

feat: [WIP] Add dedicated RESTful handler

59e3f5f

Address gemini comments

065dd38

add to allowlist

88dccab

Initial client refactor changes

7e7eba1

pstephengoogle requested a review from a team as a code owner July 24, 2025 04:34

gemini-code-assist bot reviewed Jul 24, 2025

View reviewed changes

pstephengoogle and others added 8 commits July 24, 2025 04:41

Fixes to initial client pr

89c319f

Fix typos, add comments, address gemini feedback.

2648238

More updates from gemini review.

069fff6

Update src/a2a/client/jsonrpc_client.py

38b516a

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Update src/a2a/client/client.py

8b91b34

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Fix merge conflict

0d220a3

Apply suggestions from code review

eae6e21

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

More fixes from Gemini

e19feb9

holtskinner changed the title ~~feat: Refactor client code to support multi-transport interactions and simplify client interfaces~~ refactor: Refactor client code to support multi-transport interactions and simplify client interfaces Jul 24, 2025

Merge branch 'restful' into rest_client

cf39000

gemini-code-assist bot reviewed Jul 24, 2025

View reviewed changes

holtskinner added 2 commits July 24, 2025 16:46

Spelling

fcd9828

Formatting

1ae30ee

holtskinner requested changes Jul 24, 2025

View reviewed changes

src/a2a/utils/transports.py Show resolved Hide resolved

pstephengoogle and others added 3 commits July 24, 2025 10:46

Update src/a2a/client/errors.py

4ed965f

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Updates for bugs

a1a782c

Fix more issues found by Gemini

f11246a

pstephengoogle merged commit 2a7343e into restful Jul 24, 2025
2 checks passed

pstephengoogle deleted the rest_client branch July 24, 2025 18:52

fjuma mentioned this pull request Aug 14, 2025

feat: Make the client transport agnostic a2aproject/a2a-java#231

Merged

3 tasks

-from collections.abc import AsyncGenerator
-from typing import Any, TYPE_CHECKING, Callable
-import httpx
-from httpx_sse import SSEError, aconnect_sse
-from pydantic import ValidationError
+from __future__ import annotations
+import logging
+from typing import Callable
+from a2a.utils import Transports
+from a2a.client.client import Client, ClientConfig, Consumer
+from a2a.client.jsonrpc_client import NewJsonRpcClient
+from a2a.client.grpc_client import NewGrpcClient
+from a2a.client.rest_client import NewRestfulClient
+from a2a.client.middleware import ClientCallInterceptor
+from a2a.types import (
+    AgentCapabilities,
+    AgentCard,
+)

refactor: Refactor client code to support multi-transport interactions and simplify client interfaces #342

refactor: Refactor client code to support multi-transport interactions and simplify client interfaces #342

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pstephengoogle commented Jul 24, 2025

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holtskinner commented Jul 24, 2025

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