def _normalize_result(result: EventEnvelope, result_obj: any):
if isinstance(result, EventEnvelope):
if result.get_status() == 200:
if isinstance(result.get_body(), type(result_obj)):
return result.get_body()
else:
raise AppException(500, str(result.get_body()))
else:
raise AppException(result.get_status(), str(result.get_body()))
def handle_event(self, event, instance):
headers = dict() if 'headers' not in event else event['headers']
body = None if 'body' not in event else event['body']
result = None
error_code = None
error_msg = None
# start distributed tracing if the event contains trace_id and trace_path
if 'trace_id' in event and 'trace_path' in event:
self.platform.start_tracing(self.route,
trace_id=event['trace_id'],
trace_path=event['trace_path'])
else:
self.platform.start_tracing(self.route)
# execute user function
begin = end = time.time()
try:
if instance == 0:
# service is an interceptor. e.g. inbox for RPC call
self.user_function(EventEnvelope().from_map(event))
elif instance == -1:
# service is a singleton
result = self.user_function(headers, body)
else:
# service with multiple instances
result = self.user_function(headers, body, instance)
end = time.time()
except AppException as e:
error_code = e.get_status()
error_msg = e.get_message()
except ValueError as e:
error_code = 400
error_msg = str(e)
except Exception as e:
error_code = 500
error_msg = str(e)
# execution time is rounded to 3 decimal points
exec_time = float(format((end - begin) * 1000, '.3f'))
if error_code:
if 'reply_to' in event:
# set exception as result
result = EventEnvelope().set_status(error_code).set_body(
error_msg)
else:
self.log.warn("Unhandled exception for " + self.route +
" - code=" + str(error_code) + ", message=" +
error_msg)
#
# interceptor should not send regular response because it will forward the request to another function.
# However, if error_code exists, the system will send the exception response.
# This allows interceptor to simply throw exception to indicate an error case.
#
if 'reply_to' in event and (error_code or not self.interceptor):
reply_to = event['reply_to']
# in case this is a RPC call from within
if reply_to.startswith('->'):
reply_to = reply_to[2:]
response = EventEnvelope().set_to(reply_to)
if not error_code:
response.set_exec_time(exec_time, False)
if 'extra' in event:
response.set_extra(event['extra'])
if 'cid' in event:
response.set_correlation_id(event['cid'])
if 'trace_id' in event and 'trace_path' in event:
response.set_trace(event['trace_id'], event['trace_path'])
if isinstance(result, EventEnvelope):
for h in result.get_headers():
response.set_header(h, result.get_header(h))
response.set_body(result.get_body())
response.set_status(result.get_status())
else:
response.set_body(result)
try:
self.platform.send_event(response.set_from(self.route))
except Exception as e:
self.log.warn("Event dropped because " + str(e))
# send tracing info to distributed trace logger
trace_info = self.platform.stop_tracing()
if self.tracing and trace_info is not None and isinstance(trace_info, TraceInfo) \
and trace_info.get_id() is not None and trace_info.get_path() is not None:
dt = EventEnvelope().set_to(self.DISTRIBUTED_TRACING).set_body(
trace_info.get_annotations())
dt.set_header('origin', self.platform.get_origin())
dt.set_header('id', trace_info.get_id()).set_header(
'path', trace_info.get_path())
dt.set_header('service',
self.route).set_header('start',
trace_info.get_start_time())
if not error_code:
dt.set_header('success', 'true')
dt.set_header('exec_time', exec_time)
else:
dt.set_header('success', 'false')
dt.set_header('status', error_code)
dt.set_header('exception', error_msg)
self.platform.send_event(dt)
self._loop.call_soon_threadsafe(self._ack)