Skip to content

gh-155946: Fix SMTP connection leak in logging.SMTPHandler.emit() #155947

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
americano212 wants to merge 1 commit into from
+48 −29
Closed

gh-155946: Fix SMTP connection leak in logging.SMTPHandler.emit() #155947

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
61 changes: 32 additions & 29 deletions Lib/logging/handlers.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1121,35 +1121,38 @@ def emit(self, record):
if not port:
port = smtplib.SMTP_PORT
smtp = smtplib.SMTP(self.mailhost, port, timeout=self.timeout)
msg = EmailMessage()
msg['From'] = self.fromaddr
msg['To'] = ','.join(self.toaddrs)
msg['Subject'] = self.getSubject(record)
msg['Date'] = email.utils.localtime()
msg.set_content(self.format(record))
if self.username:
if self.secure is not None:
import ssl

try:
keyfile = self.secure[0]
except IndexError:
keyfile = None

try:
certfile = self.secure[1]
except IndexError:
certfile = None

context = ssl._create_stdlib_context(
certfile=certfile, keyfile=keyfile
)
smtp.ehlo()
smtp.starttls(context=context)
smtp.ehlo()
smtp.login(self.username, self.password)
smtp.send_message(msg)
smtp.quit()
try:
msg = EmailMessage()
msg['From'] = self.fromaddr
msg['To'] = ','.join(self.toaddrs)
msg['Subject'] = self.getSubject(record)
msg['Date'] = email.utils.localtime()
msg.set_content(self.format(record))
if self.username:
if self.secure is not None:
import ssl

try:
keyfile = self.secure[0]
except IndexError:
keyfile = None

try:
certfile = self.secure[1]
except IndexError:
certfile = None

context = ssl._create_stdlib_context(
certfile=certfile, keyfile=keyfile
)
smtp.ehlo()
smtp.starttls(context=context)
smtp.ehlo()
smtp.login(self.username, self.password)
smtp.send_message(msg)
smtp.quit()
finally:
smtp.close()
except Exception:
self.handleError(record)

Expand Down
13 changes: 13 additions & 0 deletions Lib/test/test_logging.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1175,6 +1175,19 @@ def process_message(self, *args):
self.messages.append(args)
self.handled.set()

@patch('smtplib.SMTP')
def test_connection_closed_on_error(self, mock_smtp):
# gh-155946: the connection must be closed even if sending fails.
instance_mock_smtp = mock_smtp.return_value
instance_mock_smtp.send_message.side_effect = OSError('sending failed')
h = logging.handlers.SMTPHandler('localhost', 'me', 'you', 'Log')
h.handleError = Mock()
r = logging.makeLogRecord({'msg': 'Hello'})
h.emit(r)
instance_mock_smtp.close.assert_called()
h.handleError.assert_called_with(r)
h.close()

class MemoryHandlerTest(BaseTest):

"""Tests for the MemoryHandler."""
Expand Down
3 changes: 3 additions & 0 deletions Misc/NEWS.d/next/Library/2026-08-17-21-15-00.gh-issue-155946.Xq3mLp.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
Fix a connection leak in :class:`logging.handlers.SMTPHandler`: ``emit()``
now closes the SMTP connection when sending the record fails, instead of
leaving the cleanup to the garbage collector.
Loading