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Improve sample KCL app #60

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96 changes: 48 additions & 48 deletions samples/sample_kclpy_app.py
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Original file line number Diff line number Diff line change
Expand Up @@ -32,7 +32,7 @@ class RecordProcessor(processor.RecordProcessorBase):
a scaling change.
"""
def __init__(self):
self._SLEEP_SECONDS = 5
self._CHECKPOINT_SLEEP_SECONDS = 5
self._CHECKPOINT_RETRIES = 5
self._CHECKPOINT_FREQ_SECONDS = 60
self._largest_seq = (None, None)
Expand All @@ -49,7 +49,49 @@ def initialize(self, initialize_input):
self._largest_seq = (None, None)
self._last_checkpoint_time = time.time()

def checkpoint(self, checkpointer, sequence_number=None, sub_sequence_number=None):
def process_records(self, process_records_input):
"""
Called by a KCLProcess with a list of records to be processed and a checkpointer which accepts sequence numbers
from the records to indicate where in the stream to checkpoint.

:param amazon_kclpy.messages.ProcessRecordsInput process_records_input: the records, and metadata about the
records.
"""
try:
for record in process_records_input.records:
data = record.binary_data
seq = int(record.sequence_number)
sub_seq = record.sub_sequence_number
key = record.partition_key
self._process_record(data, key, seq, sub_seq)
if self._should_update_sequence(seq, sub_seq):
self._largest_seq = (seq, sub_seq)

#
# Checkpoints every self._CHECKPOINT_FREQ_SECONDS seconds
#
if time.time() - self._last_checkpoint_time > self._CHECKPOINT_FREQ_SECONDS:
self._checkpoint(process_records_input.checkpointer, str(self._largest_seq[0]), self._largest_seq[1])
self._last_checkpoint_time = time.time()

except Exception as e:
sys.stderr.write("Encountered an exception while processing records. Exception was {e}\n".format(e=e))

def _process_record(self, data, partition_key, sequence_number, sub_sequence_number):
"""
Called for each record that is passed to process_records.

:param str data: The blob of data that was contained in the record.
:param str partition_key: The key associated with this recod.
:param int sequence_number: The sequence number associated with this record.
:param int sub_sequence_number: the sub sequence number associated with this record.
"""
####################################
# Insert your processing logic here
####################################
return

def _checkpoint(self, checkpointer, sequence_number=None, sub_sequence_number=None):
"""
Checkpoints with retries on retryable exceptions.

Expand Down Expand Up @@ -80,28 +122,14 @@ def checkpoint(self, checkpointer, sequence_number=None, sub_sequence_number=Non
return
else:
print('Was throttled while checkpointing, will attempt again in {s} seconds'
.format(s=self._SLEEP_SECONDS))
.format(s=self._CHECKPOINT_SLEEP_SECONDS))
elif 'InvalidStateException' == e.value:
sys.stderr.write('MultiLangDaemon reported an invalid state while checkpointing.\n')
else: # Some other error
sys.stderr.write('Encountered an error while checkpointing, error was {e}.\n'.format(e=e))
time.sleep(self._SLEEP_SECONDS)
time.sleep(self._CHECKPOINT_SLEEP_SECONDS)

def process_record(self, data, partition_key, sequence_number, sub_sequence_number):
"""
Called for each record that is passed to process_records.

:param str data: The blob of data that was contained in the record.
:param str partition_key: The key associated with this recod.
:param int sequence_number: The sequence number associated with this record.
:param int sub_sequence_number: the sub sequence number associated with this record.
"""
####################################
# Insert your processing logic here
####################################
return

def should_update_sequence(self, sequence_number, sub_sequence_number):
def _should_update_sequence(self, sequence_number, sub_sequence_number):
"""
Determines whether a new larger sequence number is available

Expand All @@ -110,35 +138,7 @@ def should_update_sequence(self, sequence_number, sub_sequence_number):
:return boolean: true if the largest sequence should be updated, false otherwise
"""
return self._largest_seq == (None, None) or sequence_number > self._largest_seq[0] or \
(sequence_number == self._largest_seq[0] and sub_sequence_number > self._largest_seq[1])

def process_records(self, process_records_input):
"""
Called by a KCLProcess with a list of records to be processed and a checkpointer which accepts sequence numbers
from the records to indicate where in the stream to checkpoint.

:param amazon_kclpy.messages.ProcessRecordsInput process_records_input: the records, and metadata about the
records.
"""
try:
for record in process_records_input.records:
data = record.binary_data
seq = int(record.sequence_number)
sub_seq = record.sub_sequence_number
key = record.partition_key
self.process_record(data, key, seq, sub_seq)
if self.should_update_sequence(seq, sub_seq):
self._largest_seq = (seq, sub_seq)

#
# Checkpoints every self._CHECKPOINT_FREQ_SECONDS seconds
#
if time.time() - self._last_checkpoint_time > self._CHECKPOINT_FREQ_SECONDS:
self.checkpoint(process_records_input.checkpointer, str(self._largest_seq[0]), self._largest_seq[1])
self._last_checkpoint_time = time.time()

except Exception as e:
sys.stderr.write("Encountered an exception while processing records. Exception was {e}\n".format(e=e))
(sequence_number == self._largest_seq[0] and sub_sequence_number > self._largest_seq[1])

def shutdown(self, shutdown_input):
"""
Expand Down