Don't add log handlers if they already exist

.python-version

@@ -1 +1 @@
-3.13.1
+3.13

CHANGELOG.md

@@ -1,4 +1,7 @@
 # Changelog
+## v1.10.2 4/27/26
+- Prevent double logging in pytest using structlog
+
 ## v1.10.1 4/14/26
 - Add optional timeout param for OAuth2Client
 

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "nypl_py_utils"
-version = "1.10.1"
+version = "1.10.2"
 authors = [
   { name="Aaron Friedman", email="aaronfriedman@nypl.org" },
 ]

src/nypl_py_utils/functions/log_helper.py

@@ -28,9 +28,13 @@ def get_structlog(module):
     without binding it to others, use `logger = logger.bind(contextvar=0)`.
     """
     logger = logging.getLogger(module)
-    logger.addHandler(logging.StreamHandler(sys.stdout))
     logger.setLevel(os.environ.get('LOG_LEVEL', 'INFO').upper())
-    logger.propagate = False  # Prevents double logging
+
+    # We assume existing loggers will handle logging to stdout and that we
+    # don't need to do anything. Otherwise, manually add a stdout handler.
+    if not logger.hasHandlers():
+        logger.propagate = False
+        logger.addHandler(logging.StreamHandler(sys.stdout))
 
     return structlog.wrap_logger(
         logger,

tests/test_log_helper.py

@@ -10,10 +10,10 @@
 
 @freeze_time('2023-01-01 19:00:00')
 class TestLogHelper:
-    def test_json_logging(self, capsys):
+    def test_json_logging(self, caplog):
         logger = create_log('test_structlog', json=True)
         logger.info('test', some="json")
-        output = json.loads(capsys.readouterr().out)
+        output = json.loads(caplog.records[0].msg)
         assert output.get("message") == 'test'
         assert output.get("some") == 'json'
         assert output.get('level') == 'info'