From dacf8a3269f2545bf442449da60817bd6a23a7df Mon Sep 17 00:00:00 2001
From: Nejc Habjan <nejc.habjan@siemens.com>
Date: Sat, 30 Jul 2022 14:47:01 -0700
Subject: feat(client): mask tokens by default when logging

---
 docs/api-usage.rst | 21 +++++++++++++++++++++
 gitlab/client.py   | 31 ++++++++++++++++++++++++++-----
 gitlab/utils.py    | 24 ++++++++++++++++++++++++
 3 files changed, 71 insertions(+), 5 deletions(-)

diff --git a/docs/api-usage.rst b/docs/api-usage.rst
index 434de38..3c561b1 100644
--- a/docs/api-usage.rst
+++ b/docs/api-usage.rst
@@ -384,6 +384,27 @@ user. For example:
 
    p = gl.projects.create({'name': 'awesome_project'}, sudo='user1')
 
+Logging
+=======
+
+To enable debug logging from the underlying ``requests`` and ``http.client`` calls,
+you can use ``enable_debug()`` on your ``Gitlab`` instance. For example:
+
+.. code-block:: python
+
+   import os
+   import gitlab
+
+   gl = gitlab.Gitlab(private_token=os.getenv("GITLAB_TOKEN"))
+   gl.enable_debug()
+
+By default, python-gitlab will mask the token used for authentication in logging output.
+If you'd like to debug credentials sent to the API, you can disable masking explicitly:
+
+.. code-block:: python
+
+   gl.enable_debug(mask_credentials=False)
+
 .. _object_attributes:
 
 Attributes in updated objects
diff --git a/gitlab/client.py b/gitlab/client.py
index 97ca636..9f99c4f 100644
--- a/gitlab/client.py
+++ b/gitlab/client.py
@@ -524,18 +524,39 @@ class Gitlab:
                 self.http_username, self.http_password
             )
 
-    @staticmethod
-    def enable_debug() -> None:
+    def enable_debug(self, mask_credentials: bool = True) -> None:
         import logging
-        from http.client import HTTPConnection  # noqa
+        from http import client
 
-        HTTPConnection.debuglevel = 1
+        client.HTTPConnection.debuglevel = 1
         logging.basicConfig()
-        logging.getLogger().setLevel(logging.DEBUG)
+        logger = logging.getLogger()
+        logger.setLevel(logging.DEBUG)
+
+        httpclient_log = logging.getLogger("http.client")
+        httpclient_log.propagate = True
+        httpclient_log.setLevel(logging.DEBUG)
+
         requests_log = logging.getLogger("requests.packages.urllib3")
         requests_log.setLevel(logging.DEBUG)
         requests_log.propagate = True
 
+        # shadow http.client prints to log()
+        # https://stackoverflow.com/a/16337639
+        def print_as_log(*args: Any) -> None:
+            httpclient_log.log(logging.DEBUG, " ".join(args))
+
+        setattr(client, "print", print_as_log)
+
+        if not mask_credentials:
+            return
+
+        token = self.private_token or self.oauth_token or self.job_token
+        handler = logging.StreamHandler()
+        handler.setFormatter(utils.MaskingFormatter(masked=token))
+        logger.handlers.clear()
+        logger.addHandler(handler)
+
     def _get_session_opts(self) -> Dict[str, Any]:
         return {
             "headers": self.headers.copy(),
diff --git a/gitlab/utils.py b/gitlab/utils.py
index f3d97f7..7944f4c 100644
--- a/gitlab/utils.py
+++ b/gitlab/utils.py
@@ -15,6 +15,7 @@
 # You should have received a copy of the GNU Lesser General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+import logging
 import pathlib
 import traceback
 import urllib.parse
@@ -31,6 +32,29 @@ class _StdoutStream:
         print(chunk)
 
 
+class MaskingFormatter(logging.Formatter):
+    """A logging formatter that can mask credentials"""
+
+    def __init__(
+        self,
+        *args: Any,
+        masked: Optional[str] = None,
+        **kwargs: Any,
+    ) -> None:
+        super().__init__(*args, **kwargs)
+        self.masked = masked
+
+    def _filter(self, entry: str) -> str:
+        if not self.masked:
+            return entry
+
+        return entry.replace(self.masked, "[MASKED]")
+
+    def format(self, record: logging.LogRecord) -> str:
+        original = logging.Formatter.format(self, record)
+        return self._filter(original)
+
+
 def response_content(
     response: requests.Response,
     streamed: bool,
-- 
cgit v1.2.1