fix: skip deduplication for non-JSON-serializable kwargs instead of raising TypeError (#12)

src/taskiq_deduplication/middleware.py

@@ -56,7 +56,7 @@ class RedisDeduplicationMiddleware(TaskiqMiddleware):
         if self._redis is not None:
             await self._redis.aclose()
 
-    def _build_deduplication_key(self, message: TaskiqMessage) -> str:
+    def _build_deduplication_key(self, message: TaskiqMessage) -> str | None:
         explicit_key: str | None = message.labels.get(DEDUP_EXPLICIT_KEY_LABEL)
         if explicit_key is not None:
             return f"{self.key_prefix}:{explicit_key}"
@@ -67,10 +67,13 @@ class RedisDeduplicationMiddleware(TaskiqMiddleware):
             if key_fields is not None
             else message.kwargs
         )
-        payload = json.dumps(
+        try:
-            {"task": message.task_name, "kwargs": kwargs},
+            payload = json.dumps(
-            sort_keys=True,
+                {"task": message.task_name, "kwargs": kwargs},
-        )
+                sort_keys=True,
+            )
+        except TypeError:
+            return None
         fingerprint = hashlib.sha256(payload.encode()).hexdigest()[:16]
         return f"{self.key_prefix}:{fingerprint}"
 
@@ -94,6 +97,13 @@ class RedisDeduplicationMiddleware(TaskiqMiddleware):
 
         assert self._redis is not None
         key = self._build_deduplication_key(message)
+        if key is None:
+            logger.warning(
+                "Task %s has non-JSON-serializable kwargs; deduplication skipped."
+                " Use the deduplication_key label to deduplicate this task.",
+                message.task_name,
+            )
+            return message
         ttl = self._get_ttl(message.labels)
 
         logger.debug("Acquiring lock %s for task %s", key, message.task_name)
@@ -118,9 +128,10 @@ class RedisDeduplicationMiddleware(TaskiqMiddleware):
     ) -> None:
         if not self._is_enabled(message.labels):
             return
-        await self._release_if_owned(
+        key = self._build_deduplication_key(message)
-            self._build_deduplication_key(message), message.task_id
+        if key is None:
-        )
+            return
+        await self._release_if_owned(key, message.task_id)
 
     async def on_error(
         self,
@@ -130,6 +141,7 @@ class RedisDeduplicationMiddleware(TaskiqMiddleware):
     ) -> None:
         if not self._is_enabled(message.labels):
             return
-        await self._release_if_owned(
+        key = self._build_deduplication_key(message)
-            self._build_deduplication_key(message), message.task_id
+        if key is None:
-        )
+            return
+        await self._release_if_owned(key, message.task_id)

tests/test_middleware.py

@@ -92,7 +92,7 @@ class TestDefaultBuildDeduplicationKey:
         mw._redis = None
         m = make_message()
         key = mw._build_deduplication_key(m)
-        assert key.startswith("myapp:locks:")
+        assert key is not None and key.startswith("myapp:locks:")
 
     def test_empty_kwargs_produces_consistent_key(self, middleware, make_message):
         m1 = make_message(kwargs={})
@@ -128,6 +128,10 @@ class TestDefaultBuildDeduplicationKey:
         )
         assert middleware._build_deduplication_key(m) == "taskiq:deduplication:my-lock"
 
+    def test_non_serializable_kwargs_returns_none(self, middleware, make_message):
+        m = make_message(kwargs={"dt": object()})
+        assert middleware._build_deduplication_key(m) is None
+
 
 class TestPreSend:
     @pytest.mark.anyio
@@ -174,6 +178,15 @@ class TestPreSend:
         await middleware.pre_send(make_message(kwargs={"x": 1}))
         await middleware.pre_send(make_message(kwargs={"x": 2}))
 
+    @pytest.mark.anyio
+    async def test_non_serializable_kwargs_skips_deduplication(
+        self, middleware, make_message
+    ):
+        msg1 = make_message(kwargs={"dt": object()})
+        msg2 = make_message(kwargs={"dt": object()})
+        await middleware.pre_send(msg1)
+        await middleware.pre_send(msg2)  # should not raise
+
     @pytest.mark.anyio
     async def test_default_ttl_applied(self, fake_redis, make_message):
         mw = RedisDeduplicationMiddleware(redis_url="redis://localhost", default_ttl=77)