def __call__(self, difference, old_val, new_val):
kwargs = {}
kwargs.update(self.extra_kwargs)
kwargs["record"] = self.record
kwargs["callback_id"] = self.callback_id
kwargs["difference"] = difference
kwargs["changes"] = self.record._convert_diff_to_changelist(
difference, old_val, new_val
)
logger.debug(f"Firing callback {self.callback} with kwargs: {kwargs}")
# trim down the passed parameters
# to include only those the callback will accept
params = signature(self.callback).parameters
if not any(["**" in str(p) for p in params.values()]):
# there's no "**kwargs" in the callback signature,
# so remove any unaccepted params
for arg in kwargs.keys():
if arg not in params:
del kwargs[arg]
# perform the callback, gracefully handling any exceptions
try:
# trigger the callback within its own thread,
# so it won't block others if it's long-running
Thread(target=self.callback, kwargs=kwargs, daemon=True).start()
except Exception as e:
logger.error(
f"Error while processing callback for {repr(self.record)}: {repr(e)}"
)
def poll_forever(self):
"""
Call `poll()` in never-ending loop with small time intervals in-between.
This function is blocking, it never returns!
"""
while True:
try:
self.poll()
except Exception as e:
logger.error("Encountered error during polling!")
logger.error(e, exc_info=True)
time.sleep(1)
def poll(self, retries: int = 10):
"""
Poll for changes.
Arguments
---------
retries : int, optional
Number of times to retry request if it fails.
Defaults to 10.
Raises
------
HTTPError
When GET request fails for `retries` times.
"""
logger.debug("Starting new long-poll request")
while retries:
try:
response = self.client.session.get(self.url(EIO=3, sid=self.sid))
response.raise_for_status()
retries -= 1
except HTTPError as e:
try:
message = f"{response.content} / {e}"
except AttributeError:
message = str(e)
logger.warn(
f"Problem with submitting poll request: {message} (will retry {retries} more times)"
)
time.sleep(0.1)
if retries <= 0:
raise
if retries <= 5:
logger.error(
f"Persistent error submitting poll request: {message} (will retry {retries} more times)"
)
# if we're close to giving up, also try reinitializing the session
self.initialize()
self._refresh_updated_records(
self._decode_numbered_json_thing(response.content)
)
def __init__(self, message: str, **extra):
dumped_data = json.dumps(extra, indent=2)
logger.error(f"Exception: {dumped_data}")
super().__init__(message)