def release_salmon(self):
"""Attempts to unlease the salmon entity.
"""
salmon = db.get(self.request.params["salmon_key"])
if salmon and salmon.status == "processing":
salmon.status = "new"
salmon.leased_until = None
salmon.save()
def complete_salmon(self):
"""Attempts to mark the salmon entity completed.
Returns True on success, False otherwise.
"""
salmon = db.get(self.request.params["salmon_key"])
if salmon is None:
raise exc.HTTPExpectationFailed("salmon entity disappeared!")
elif salmon.status == "complete":
# let this response return 200 and finish
logging.warning("salmon stolen and finished. did my lease expire?")
return
elif salmon.status == "new":
raise exc.HTTPExpectationFailed("salmon went backward from processing to new!")
assert salmon.status == "processing"
salmon.status = "complete"
salmon.save()
def lease_salmon(self):
"""Attempts to acquire and lease the salmon entity.
Returns the Salmon on success, otherwise None.
TODO: unify with complete_salmon
"""
salmon = db.get(self.request.params["salmon_key"])
if salmon is None:
raise exc.HTTPExpectationFailed("no salmon entity!")
elif salmon.status == "complete":
# let this response return 200 and finish
logging.warning("duplicate task already propagated salmon")
elif salmon.status == "processing" and NOW_FN() < salmon.leased_until:
# return error code, but don't raise an exception because we don't want
# the exception handler in post() to catch it and try to release the lease.
raise exc.HTTPConflict("duplicate task is currently processing!")
else:
assert salmon.status in ("new", "processing")
salmon.status = "processing"
salmon.leased_until = NOW_FN() + self.LEASE_LENGTH
salmon.save()
return salmon