Pool of _ServerSession objects. This class is thread-safe.
| 1207 | |
| 1208 | |
| 1209 | class _ServerSessionPool(collections.deque): # type: ignore[type-arg] |
| 1210 | """Pool of _ServerSession objects. |
| 1211 | |
| 1212 | This class is thread-safe. |
| 1213 | """ |
| 1214 | |
| 1215 | def __init__(self, *args: Any, **kwargs: Any): |
| 1216 | super().__init__(*args, **kwargs) |
| 1217 | self.generation = 0 |
| 1218 | |
| 1219 | def reset(self) -> None: |
| 1220 | self.generation += 1 |
| 1221 | self.clear() |
| 1222 | |
| 1223 | def pop_all(self) -> list[_ServerSession]: |
| 1224 | ids = [] |
| 1225 | while True: |
| 1226 | try: |
| 1227 | ids.append(self.pop().session_id) |
| 1228 | except IndexError: |
| 1229 | break |
| 1230 | return ids |
| 1231 | |
| 1232 | def get_server_session(self, session_timeout_minutes: Optional[int]) -> _ServerSession: |
| 1233 | # Although the Driver Sessions Spec says we only clear stale sessions |
| 1234 | # in return_server_session, PyMongo can't take a lock when returning |
| 1235 | # sessions from a __del__ method (like in AsyncCursor.__die), so it can't |
| 1236 | # clear stale sessions there. In case many sessions were returned via |
| 1237 | # __del__, check for stale sessions here too. |
| 1238 | self._clear_stale(session_timeout_minutes) |
| 1239 | |
| 1240 | # The most recently used sessions are on the left. |
| 1241 | while True: |
| 1242 | try: |
| 1243 | s = self.popleft() |
| 1244 | except IndexError: |
| 1245 | break |
| 1246 | if not s.timed_out(session_timeout_minutes): |
| 1247 | return s |
| 1248 | |
| 1249 | return _ServerSession(self.generation) |
| 1250 | |
| 1251 | def return_server_session(self, server_session: _ServerSession) -> None: |
| 1252 | # Discard sessions from an old pool to avoid duplicate sessions in the |
| 1253 | # child process after a fork. |
| 1254 | if server_session.generation == self.generation and not server_session.dirty: |
| 1255 | self.appendleft(server_session) |
| 1256 | |
| 1257 | def _clear_stale(self, session_timeout_minutes: Optional[int]) -> None: |
| 1258 | # Clear stale sessions. The least recently used are on the right. |
| 1259 | while True: |
| 1260 | try: |
| 1261 | s = self.pop() |
| 1262 | except IndexError: |
| 1263 | break |
| 1264 | if not s.timed_out(session_timeout_minutes): |
| 1265 | self.append(s) |
| 1266 | # The remaining sessions also haven't timed out. |