PYTHON-5292 - Debug logs should only output on test failure

Author: NoahStapp

.evergreen/scripts/run_tests.py

@@ -173,7 +173,6 @@ def run() -> None:
         return
 
     # Run local tests.
-    print(f"Running tests with args: {TEST_ARGS + sys.argv[1:]}")
     ret = pytest.main(TEST_ARGS + sys.argv[1:])
     if ret != 0:
         sys.exit(ret)

.evergreen/scripts/setup_tests.py

@@ -465,7 +465,7 @@ def handle_test_env() -> None:
         UV_ARGS.append(f"--group {framework}")
 
     else:
-        TEST_ARGS = f"-v --capture=no --show-capture=no --durations=5 {TEST_ARGS}"
+        TEST_ARGS = f"-v --durations=5 {TEST_ARGS}"
         TEST_SUITE = TEST_SUITE_MAP.get(test_name)
         if TEST_SUITE:
             TEST_ARGS = f"-m {TEST_SUITE} {TEST_ARGS}"

CONTRIBUTING.md

@@ -351,11 +351,11 @@ If you are running one of the `no-responder` tests, omit the `run-server` step.
 
 ## Enable Debug Logs
 
-- Use `-o log_cli_level="DEBUG" -o log_cli=1` with `just test` or `pytest`.
-- Add `log_cli_level = "DEBUG` and `log_cli = 1` to the `tool.pytest.ini_options` section in `pyproject.toml` for Evergreen patches or to enable debug logs by default on your machine.
-- You can also set `DEBUG_LOG=1` and run either `just setup-tests` or `just-test`.
+- Use `-o log_cli_level="DEBUG" -o log_cli=1` with `just test` or `pytest` to output all debug logs to the terminal. **Warning**: This will output a huge amount of logs.
+- Add `log_cli_level = "DEBUG` to the `tool.pytest.ini_options` section in `pyproject.toml` to enable debug logs in this manner by default on your machine.
+- Set `DEBUG_LOG=1` and run `just setup-tests`, `just-test`, or `pytest` to enable debug logs only for failed tests.
 - Finally, you can use `just setup-tests --debug-log`.
-- For evergreen patch builds, you can use `evergreen patch --param DEBUG_LOG=1` to enable debug logs for the patch.
+- For evergreen patch builds, you can use `evergreen patch --param DEBUG_LOG=1` to enable debug logs for failed tests in the patch.
 
 ## Adding a new test suite
 

pymongo/logger.py

@@ -95,48 +95,14 @@ class _SDAMStatusMessage(str, enum.Enum):
     ConnectionClosedReason.IDLE: "Connection was idle too long",
     ConnectionCheckOutFailedReason.TIMEOUT: "Connection exceeded the specified timeout",
 }
-_DEBUG_LOG_HANDLER = None
-
-
-# Custom logging handler to ensure we only flush the buffered logs on a test failure
-class LoggingHandler(logging.handlers.MemoryHandler):
-    def __init__(self, capacity=1000, target=None):
-        super().__init__(capacity, logging.DEBUG, target, flushOnClose=False)
-        self.original_capacity = capacity
-
-    def shouldFlush(self, record):
-        if len(self.buffer) >= self.capacity:
-            self.capacity = len(self.buffer) * 2
-        return False
-
-    def flush(self):
-        super().flush()
-        self.capacity = self.original_capacity
-
-    def clear(self):
-        with self.lock:
-            self.buffer.clear()
-            self.capacity = self.original_capacity
-
 
 if os.environ.get("DEBUG_LOG"):
-    FORMAT = "%(levelname)s %(name)s %(message)s"
-    handler = logging.StreamHandler()
-    handler.setFormatter(logging.Formatter(FORMAT))
-    _DEBUG_LOG_HANDLER = LoggingHandler(target=handler)
-
     _COMMAND_LOGGER.setLevel(logging.DEBUG)
     _SERVER_SELECTION_LOGGER.setLevel(logging.DEBUG)
     _CONNECTION_LOGGER.setLevel(logging.DEBUG)
     _CLIENT_LOGGER.setLevel(logging.DEBUG)
     _SDAM_LOGGER.setLevel(logging.DEBUG)
 
-    _COMMAND_LOGGER.addHandler(_DEBUG_LOG_HANDLER)
-    _SERVER_SELECTION_LOGGER.addHandler(_DEBUG_LOG_HANDLER)
-    _CONNECTION_LOGGER.addHandler(_DEBUG_LOG_HANDLER)
-    _CLIENT_LOGGER.addHandler(_DEBUG_LOG_HANDLER)
-    _SDAM_LOGGER.addHandler(_DEBUG_LOG_HANDLER)
-
 
 def _log_client_error() -> None:
     # This is called from a daemon thread so check for None to account for interpreter shutdown.

pyproject.toml

@@ -98,6 +98,7 @@ minversion = "7"
 addopts = ["-ra", "--strict-config", "--strict-markers", "--junitxml=xunit-results/TEST-results.xml", "-m default or default_async"]
 testpaths = ["test"]
 log_cli_level = "INFO"
+log_cli = true
 faulthandler_timeout = 1500
 asyncio_default_fixture_loop_scope = "session"
 xfail_strict = true

test/asynchronous/conftest.py

@@ -8,24 +8,9 @@
 import pytest
 import pytest_asyncio
 
-from pymongo.logger import _DEBUG_LOG_HANDLER
-
 _IS_SYNC = False
 
 
-@pytest.hookimpl(hookwrapper=True)
-def pytest_runtest_makereport(item):
-    if _DEBUG_LOG_HANDLER is not None:
-        outcome = yield
-        rep = outcome.get_result()
-        if rep.failed:
-            _DEBUG_LOG_HANDLER.flush()
-        else:
-            _DEBUG_LOG_HANDLER.clear()
-    else:
-        yield
-
-
 @pytest.fixture(scope="session")
 def event_loop_policy():
     # The default asyncio loop implementation on Windows

test/conftest.py

@@ -6,24 +6,9 @@
 
 import pytest
 
-from pymongo.logger import _DEBUG_LOG_HANDLER
-
 _IS_SYNC = True
 
 
-@pytest.hookimpl(hookwrapper=True)
-def pytest_runtest_makereport(item):
-    if _DEBUG_LOG_HANDLER is not None:
-        outcome = yield
-        rep = outcome.get_result()
-        if rep.failed:
-            _DEBUG_LOG_HANDLER.flush()
-        else:
-            _DEBUG_LOG_HANDLER.clear()
-    else:
-        yield
-
-
 @pytest.fixture(scope="session")
 def event_loop_policy():
     # The default asyncio loop implementation on Windows