def get_next_txn(self, txn: LoggingTransaction):
"""
Usage:
stream_id = stream_id_gen.get_next(txn)
# ... persist event ...
"""
next_id = self._load_next_id_txn(txn)
with self._lock:
self._unfinished_ids.add(next_id)
txn.call_after(self._mark_id_as_finished, next_id)
txn.call_on_exception(self._mark_id_as_finished, next_id)
# Update the `stream_positions` table with newly updated stream
# ID (unless self._writers is not set in which case we don't
# bother, as nothing will read it).
#
# We only do this on the success path so that the persisted current
# position points to a persisted row with the correct instance name.
if self._writers:
txn.call_after(
run_as_background_process,
"MultiWriterIdGenerator._update_table",
self._db.runInteraction,
"MultiWriterIdGenerator._update_table",
self._update_stream_positions_table_txn,
)
return self._return_factor * next_id
def get_next_txn(self, txn: LoggingTransaction) -> int:
"""
Usage:
stream_id = stream_id_gen.get_next(txn)
# ... persist event ...
"""
# If we have a list of instances that are allowed to write to this
# stream, make sure we're in it.
if self._writers and self._instance_name not in self._writers:
raise Exception("Tried to allocate stream ID on non-writer")
next_id = self._load_next_id_txn(txn)
txn.call_after(self._mark_id_as_finished, next_id)
txn.call_on_exception(self._mark_id_as_finished, next_id)
# Update the `stream_positions` table with newly updated stream
# ID (unless self._writers is not set in which case we don't
# bother, as nothing will read it).
#
# We only do this on the success path so that the persisted current
# position points to a persisted row with the correct instance name.
if self._writers:
txn.call_after(
run_as_background_process,
"MultiWriterIdGenerator._update_table",
self._db.runInteraction,
"MultiWriterIdGenerator._update_table",
self._update_stream_positions_table_txn,
)
return self._return_factor * next_id
def get_next_txn(self, txn: LoggingTransaction):
"""
Usage:
stream_id = stream_id_gen.get_next(txn)
# ... persist event ...
"""
next_id = self._load_next_id_txn(txn)
with self._lock:
self._unfinished_ids.add(next_id)
txn.call_after(self._mark_id_as_finished, next_id)
txn.call_on_exception(self._mark_id_as_finished, next_id)
return next_id
def _test_txn(txn: LoggingTransaction) -> None:
txn.call_after(after_callback, 123, 456, extra=789)
txn.call_on_exception(exception_callback, 987, 654, extra=321)
func(txn)
def _test_txn(txn: LoggingTransaction) -> None:
txn.call_after(after_callback, 123, 456, extra=789)
txn.call_on_exception(exception_callback, 987, 654, extra=321)
d.cancel()
# Simulate a retryable failure on every attempt.
raise self.db_pool.engine.module.OperationalError()
