diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index a8403d4..f2fcdb9 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -48,16 +48,16 @@ jobs:
         id: poetry-cache
         with:
           path: ~/.local
-          key: key-0
+          key: ${{ matrix.python-version }}-1
       - uses: snok/install-poetry@v1
         with:
           virtualenvs-create: false
-          version: 1.1.11
+          version: 1.1.12
       - uses: actions/cache@v2
         id: cache-venv
         with:
           path: .venv
-          key: ${{ hashFiles('**/poetry.lock') }}-${{ matrix.python-version }}-0
+          key: ${{ hashFiles('**/poetry.lock') }}-${{ matrix.python-version }}-1
       - run: |
           python -m venv .venv
           source .venv/bin/activate
diff --git a/asgi_correlation_id/log_filters.py b/asgi_correlation_id/log_filters.py
index 717d105..c46e036 100644
--- a/asgi_correlation_id/log_filters.py
+++ b/asgi_correlation_id/log_filters.py
@@ -1,12 +1,12 @@
 from logging import Filter, LogRecord
-from typing import Type
+from typing import Optional, Type
 
 from asgi_correlation_id.context import celery_current_id, celery_parent_id, correlation_id
 
 # Middleware
 
 
-def correlation_id_filter(uuid_length: int = 32) -> Type[Filter]:
+def correlation_id_filter(uuid_length: Optional[int] = None) -> Type[Filter]:
     class CorrelationId(Filter):
         def filter(self, record: LogRecord) -> bool:
             """
@@ -18,7 +18,10 @@ def filter(self, record: LogRecord) -> bool:
             metadata.
             """
             cid = correlation_id.get()
-            record.correlation_id = cid[:uuid_length] if cid else cid  # type: ignore[attr-defined]
+            if uuid_length is not None and cid:
+                record.correlation_id = cid[:uuid_length]  # type: ignore[attr-defined]
+            else:
+                record.correlation_id = cid  # type: ignore[attr-defined]
             return True
 
     return CorrelationId
diff --git a/tests/test_log_filter.py b/tests/test_log_filter.py
new file mode 100644
index 0000000..381a549
--- /dev/null
+++ b/tests/test_log_filter.py
@@ -0,0 +1,21 @@
+from unittest.mock import Mock
+from uuid import uuid4
+
+from asgi_correlation_id import correlation_id_filter
+from asgi_correlation_id.context import correlation_id
+
+
+def test_correlation_id_filter():
+    mock_record = Mock()
+
+    cid = uuid4().hex
+    correlation_id.set(cid)
+
+    # Call with no uuid length
+    correlation_id_filter(None)().filter(mock_record)
+    assert mock_record.correlation_id == cid
+
+    # Call with uuid length
+    for length in [0, 14, 30, 100]:
+        correlation_id_filter(uuid_length=length)().filter(mock_record)
+        assert mock_record.correlation_id == cid[:length]
diff --git a/tests/test_middleware.py b/tests/test_middleware.py
index 7a97be2..0136a77 100644
--- a/tests/test_middleware.py
+++ b/tests/test_middleware.py
@@ -82,7 +82,7 @@ async def test_websocket_request(caplog):
 
 
 @app.get('/access-control-expose-headers')
-async def access_control_view() -> dict:
+async def access_control_view() -> Response:
     return Response(status_code=204, headers={'Access-Control-Expose-Headers': 'test1, test2'})