fix(channels): centralize shared channel retry helpers (#3583)

backend/app/channels/base.py

@@ -2,14 +2,19 @@
 
 from __future__ import annotations
 
+import asyncio
 import logging
 from abc import ABC, abstractmethod
-from typing import Any
+from collections.abc import Awaitable, Callable
+from concurrent.futures import CancelledError as FutureCancelledError
+from typing import Any, TypeVar
 
 from app.channels.message_bus import InboundMessage, InboundMessageType, MessageBus, OutboundMessage, ResolvedAttachment
 
 logger = logging.getLogger(__name__)
 
+T = TypeVar("T")
+
 
 class Channel(ABC):
     """Base class for all IM channel implementations.
@@ -65,6 +70,53 @@ class Channel(ABC):
 
     # -- helpers -----------------------------------------------------------
 
+    async def _send_with_retry(
+        self,
+        operation: Callable[[], Awaitable[T]],
+        *,
+        max_retries: int,
+        log_prefix: str | None = None,
+        operation_name: str = "send",
+    ) -> T:
+        """Run an outbound send operation with the shared channel retry policy."""
+        prefix = log_prefix or f"[{self.name}]"
+        last_exc: Exception | None = None
+        for attempt in range(max_retries):
+            try:
+                return await operation()
+            except Exception as exc:
+                last_exc = exc
+                if attempt < max_retries - 1:
+                    delay = 2**attempt
+                    logger.warning(
+                        "%s %s failed (attempt %d/%d), retrying in %ds: %s",
+                        prefix,
+                        operation_name,
+                        attempt + 1,
+                        max_retries,
+                        delay,
+                        exc,
+                    )
+                    await asyncio.sleep(delay)
+
+        logger.error("%s %s failed after %d attempts: %s", prefix, operation_name, max_retries, last_exc)
+        if last_exc is None:
+            raise RuntimeError(f"{self.name} {operation_name} failed without an exception from any attempt")
+        raise last_exc
+
+    def _log_future_error(self, fut: Any, name: str, msg_id: Any) -> None:
+        """Callback for concurrent futures scheduled from channel worker threads."""
+        try:
+            exc = fut.exception()
+        except (asyncio.CancelledError, FutureCancelledError, asyncio.InvalidStateError):
+            return
+        except Exception:
+            logger.exception("[%s] failed to inspect future for %s (msg_id=%s)", self.name, name, msg_id)
+            return
+
+        if exc:
+            logger.error("[%s] %s failed for msg_id=%s: %s", self.name, name, msg_id, exc)
+
     def _make_inbound(
         self,
         chat_id: str,

backend/app/channels/dingtalk.py

@@ -247,32 +247,19 @@ class DingTalkChannel(Channel):
                 self._card_repliers.pop(out_track_id, None)
             return
 
-        # Non-card mode: send sampleMarkdown with retry
+        async def send_markdown() -> None:
-        last_exc: Exception | None = None
-        for attempt in range(_max_retries):
-            try:
             if conversation_type == _CONVERSATION_TYPE_GROUP:
                 await self._send_group_message(robot_code, conversation_id, msg.text, at_user_ids=[sender_staff_id] if sender_staff_id else None)
             else:
                 await self._send_p2p_message(robot_code, sender_staff_id, msg.text)
-                return
-            except Exception as exc:
-                last_exc = exc
-                if attempt < _max_retries - 1:
-                    delay = 2**attempt
-                    logger.warning(
-                        "[DingTalk] send failed (attempt %d/%d), retrying in %ds: %s",
-                        attempt + 1,
-                        _max_retries,
-                        delay,
-                        exc,
-                    )
-                    await asyncio.sleep(delay)
 
-        logger.error("[DingTalk] send failed after %d attempts: %s", _max_retries, last_exc)
+        # Non-card mode: send sampleMarkdown with retry
-        if last_exc is None:
+        await self._send_with_retry(
-            raise RuntimeError("DingTalk send failed without an exception from any attempt")
+            send_markdown,
-        raise last_exc
+            max_retries=_max_retries,
+            log_prefix="[DingTalk]",
+        )
+        return
 
     async def _send_markdown_fallback(
         self,
@@ -802,15 +789,6 @@ class DingTalkChannel(Channel):
             logger.exception("[DingTalk] failed to upload media: %s", file_path)
             return None
 
-    @staticmethod
-    def _log_future_error(fut: Any, name: str, msg_id: str) -> None:
-        try:
-            exc = fut.exception()
-            if exc:
-                logger.error("[DingTalk] %s failed for msg_id=%s: %s", name, msg_id, exc)
-        except (asyncio.CancelledError, asyncio.InvalidStateError):
-            pass
-
 
 class _DingTalkMessageHandler:
     """Callback handler registered with dingtalk-stream."""

backend/app/channels/feishu.py

@@ -241,28 +241,11 @@ class FeishuChannel(Channel):
             len(msg.text),
         )
 
-        last_exc: Exception | None = None
+        await self._send_with_retry(
-        for attempt in range(_max_retries):
+            lambda: self._send_card_message(msg),
-            try:
+            max_retries=_max_retries,
-                await self._send_card_message(msg)
+            log_prefix="[Feishu]",
-                return  # success
-            except Exception as exc:
-                last_exc = exc
-                if attempt < _max_retries - 1:
-                    delay = 2**attempt  # 1s, 2s
-                    logger.warning(
-                        "[Feishu] send failed (attempt %d/%d), retrying in %ds: %s",
-                        attempt + 1,
-                        _max_retries,
-                        delay,
-                        exc,
         )
-                    await asyncio.sleep(delay)
-
-        logger.error("[Feishu] send failed after %d attempts: %s", _max_retries, last_exc)
-        if last_exc is None:
-            raise RuntimeError("Feishu send failed without an exception from any attempt")
-        raise last_exc
 
     async def send_file(self, msg: OutboundMessage, attachment: ResolvedAttachment) -> bool:
         if not self._api_client:
@@ -725,16 +708,6 @@ class FeishuChannel(Channel):
 
         return root_id or msg_id, False
 
-    @staticmethod
-    def _log_future_error(fut, name: str, msg_id: str) -> None:
-        """Callback for run_coroutine_threadsafe futures to surface errors."""
-        try:
-            exc = fut.exception()
-            if exc:
-                logger.error("[Feishu] %s failed for msg_id=%s: %s", name, msg_id, exc)
-        except Exception:
-            pass
-
     @staticmethod
     def _log_task_error(task: asyncio.Task, name: str, msg_id: str) -> None:
         """Callback for background asyncio tasks to surface errors."""

backend/app/channels/slack.py

@@ -141,9 +141,7 @@ class SlackChannel(Channel):
         if msg.thread_ts:
             kwargs["thread_ts"] = msg.thread_ts
 
-        last_exc: Exception | None = None
+        async def post_message() -> None:
-        for attempt in range(_max_retries):
-            try:
             await asyncio.to_thread(web_client.chat_postMessage, **kwargs)
             # Add a completion reaction to the thread root
             if msg.thread_ts:
@@ -154,21 +152,14 @@ class SlackChannel(Channel):
                     msg.thread_ts,
                     "white_check_mark",
                 )
-                return
-            except Exception as exc:
-                last_exc = exc
-                if attempt < _max_retries - 1:
-                    delay = 2**attempt  # 1s, 2s
-                    logger.warning(
-                        "[Slack] send failed (attempt %d/%d), retrying in %ds: %s",
-                        attempt + 1,
-                        _max_retries,
-                        delay,
-                        exc,
-                    )
-                    await asyncio.sleep(delay)
 
-        logger.error("[Slack] send failed after %d attempts: %s", _max_retries, last_exc)
+        try:
+            await self._send_with_retry(
+                post_message,
+                max_retries=_max_retries,
+                log_prefix="[Slack]",
+            )
+        except Exception:
             # Add failure reaction on error
             if msg.thread_ts:
                 try:
@@ -181,9 +172,7 @@ class SlackChannel(Channel):
                     )
                 except Exception:
                     pass
-        if last_exc is None:
+            raise
-            raise RuntimeError("Slack send failed without an exception from any attempt")
-        raise last_exc
 
     async def send_file(self, msg: OutboundMessage, attachment: ResolvedAttachment) -> bool:
         web_client = await self._get_web_client_for_message(msg)

backend/app/channels/telegram.py

@@ -239,29 +239,17 @@ class TelegramChannel(Channel):
             kwargs["reply_to_message_id"] = reply_to
 
         bot = self._application.bot
-        last_exc: Exception | None = None
+
-        for attempt in range(_max_retries):
+        async def send_message() -> int:
-            try:
             sent = await bot.send_message(**kwargs)
             self._last_bot_message[chat_key] = sent.message_id
             return sent.message_id
-            except Exception as exc:
-                last_exc = exc
-                if attempt < _max_retries - 1:
-                    delay = 2**attempt  # 1s, 2s
-                    logger.warning(
-                        "[Telegram] send failed (attempt %d/%d), retrying in %ds: %s",
-                        attempt + 1,
-                        _max_retries,
-                        delay,
-                        exc,
-                    )
-                    await asyncio.sleep(delay)
 
-        logger.error("[Telegram] send failed after %d attempts: %s", _max_retries, last_exc)
+        return await self._send_with_retry(
-        if last_exc is None:
+            send_message,
-            raise RuntimeError("Telegram send failed without an exception from any attempt")
+            max_retries=_max_retries,
-        raise last_exc
+            log_prefix="[Telegram]",
+        )
 
     async def send_file(self, msg: OutboundMessage, attachment: ResolvedAttachment) -> bool:
         if not self._application:
@@ -368,16 +356,6 @@ class TelegramChannel(Channel):
         except Exception:
             logger.exception("[Telegram] failed to send running reply in chat=%s", chat_id)
 
-    # -- internal ----------------------------------------------------------
-    @staticmethod
-    def _log_future_error(fut, name: str, msg_id: str):
-        try:
-            exc = fut.exception()
-            if exc:
-                logger.error("[Telegram] %s failed for msg_id=%s: %s", name, msg_id, exc)
-        except Exception:
-            logger.exception("[Telegram] Failed to inspect future for %s (msg_id=%s)", name, msg_id)
-
     def _run_polling(self) -> None:
         """Run telegram polling in a dedicated thread."""
         self._tg_loop = asyncio.new_event_loop()

backend/app/channels/wechat.py

@@ -342,27 +342,15 @@ class WechatChannel(Channel):
             "base_info": self._base_info(),
         }
 
-        last_exc: Exception | None = None
+        async def send_message() -> None:
-        for attempt in range(max_retries):
-            try:
             data = await self._request_json("/ilink/bot/sendmessage", payload)
             self._ensure_success(data, "sendmessage")
-                return
-            except Exception as exc:
-                last_exc = exc
-                if attempt < max_retries - 1:
-                    delay = 2**attempt
-                    logger.warning(
-                        "[WeChat] send failed (attempt %d/%d), retrying in %ds: %s",
-                        attempt + 1,
-                        max_retries,
-                        delay,
-                        exc,
-                    )
-                    await asyncio.sleep(delay)
 
-        logger.error("[WeChat] send failed after %d attempts: %s", max_retries, last_exc)
+        await self._send_with_retry(
-        raise last_exc  # type: ignore[misc]
+            send_message,
+            max_retries=max_retries,
+            log_prefix="[WeChat]",
+        )
 
     async def send_file(self, msg: OutboundMessage, attachment: ResolvedAttachment) -> bool:
         if attachment.is_image:

backend/app/channels/wecom.py

@@ -389,30 +389,20 @@ class WeComChannel(Channel):
             if not stream_id:
                 return
 
-            last_exc: Exception | None = None
+            await self._send_with_retry(
-            for attempt in range(_max_retries):
+                lambda: self._ws_client.reply_stream(frame, stream_id, msg.text, bool(msg.is_final)),
-                try:
+                max_retries=_max_retries,
-                    await self._ws_client.reply_stream(frame, stream_id, msg.text, bool(msg.is_final))
+                log_prefix="[WeCom]",
+                operation_name="stream send",
+            )
             return
-                except Exception as exc:
-                    last_exc = exc
-                    if attempt < _max_retries - 1:
-                        await asyncio.sleep(2**attempt)
-            if last_exc:
-                raise last_exc
 
         body = {"msgtype": "markdown", "markdown": {"content": msg.text}}
-        last_exc = None
+        await self._send_with_retry(
-        for attempt in range(_max_retries):
+            lambda: self._ws_client.send_message(msg.chat_id, body),
-            try:
+            max_retries=_max_retries,
-                await self._ws_client.send_message(msg.chat_id, body)
+            log_prefix="[WeCom]",
-                return
+        )
-            except Exception as exc:
-                last_exc = exc
-                if attempt < _max_retries - 1:
-                    await asyncio.sleep(2**attempt)
-        if last_exc:
-            raise last_exc
 
     async def _upload_media_ws(
         self,

backend/tests/test_channels.py

@@ -4,7 +4,9 @@ from __future__ import annotations
 
 import asyncio
 import json
+import logging
 import tempfile
+from concurrent.futures import Future
 from pathlib import Path
 from types import SimpleNamespace
 from unittest.mock import AsyncMock, MagicMock, patch
@@ -333,6 +335,71 @@ class TestChannelBase:
 
         _run(go())
 
+    def test_send_with_retry_retries_until_success(self, monkeypatch):
+        bus = MessageBus()
+        ch = DummyChannel(bus)
+        attempts = 0
+        sleep = AsyncMock()
+        monkeypatch.setattr("app.channels.base.asyncio.sleep", sleep)
+
+        async def flaky_send():
+            nonlocal attempts
+            attempts += 1
+            if attempts < 3:
+                raise RuntimeError(f"failure {attempts}")
+            return "sent"
+
+        result = _run(ch._send_with_retry(flaky_send, max_retries=3, log_prefix="[Dummy]"))
+
+        assert result == "sent"
+        assert attempts == 3
+        assert [call.args[0] for call in sleep.await_args_list] == [1, 2]
+
+    def test_log_future_error_handles_cancelled_future(self, caplog):
+        bus = MessageBus()
+        ch = DummyChannel(bus)
+        fut = Future()
+        fut.cancel()
+
+        with caplog.at_level(logging.ERROR):
+            ch._log_future_error(fut, "prepare_inbound", "m1")
+
+        assert "prepare_inbound" not in caplog.text
+
+    def test_log_future_error_surfaces_future_exception(self, caplog):
+        bus = MessageBus()
+        ch = DummyChannel(bus)
+        fut = Future()
+        fut.set_exception(RuntimeError("boom"))
+
+        with caplog.at_level(logging.ERROR):
+            ch._log_future_error(fut, "prepare_inbound", "m1")
+
+        assert "prepare_inbound failed for msg_id=m1: boom" in caplog.text
+
+    def test_channel_capabilities_match_channel_defaults(self):
+        from app.channels.dingtalk import DingTalkChannel
+        from app.channels.discord import DiscordChannel
+        from app.channels.feishu import FeishuChannel
+        from app.channels.manager import CHANNEL_CAPABILITIES
+        from app.channels.slack import SlackChannel
+        from app.channels.telegram import TelegramChannel
+        from app.channels.wechat import WechatChannel
+        from app.channels.wecom import WeComChannel
+
+        bus = MessageBus()
+        defaults = {
+            "dingtalk": DingTalkChannel(bus=bus, config={}).supports_streaming,
+            "discord": DiscordChannel(bus=bus, config={}).supports_streaming,
+            "feishu": FeishuChannel(bus=bus, config={}).supports_streaming,
+            "slack": SlackChannel(bus=bus, config={}).supports_streaming,
+            "telegram": TelegramChannel(bus=bus, config={}).supports_streaming,
+            "wechat": WechatChannel(bus=bus, config={}).supports_streaming,
+            "wecom": WeComChannel(bus=bus, config={}).supports_streaming,
+        }
+
+        assert {name: caps["supports_streaming"] for name, caps in CHANNEL_CAPABILITIES.items()} == defaults
+
 
 # ---------------------------------------------------------------------------
 # _extract_response_text tests