def connect_kinesis(aws_access_key_id=None,
aws_secret_access_key=None,
**kwargs):
"""
Connect to Amazon Kinesis
:type aws_access_key_id: string
:param aws_access_key_id: Your AWS Access Key ID
:type aws_secret_access_key: string
:param aws_secret_access_key: Your AWS Secret Access Key
rtype: :class:`boto.kinesis.layer1.KinesisConnection`
:return: A connection to the Amazon Kinesis service
"""
from boto.kinesis.layer1 import KinesisConnection
return KinesisConnection(aws_access_key_id=aws_access_key_id,
aws_secret_access_key=aws_secret_access_key,
**kwargs)
def __init__(self, stream, shard_id, session, connection=None, limit=None):
self.stream = stream
self.shard_id = shard_id
self.limit = limit
self.session = session
if connection is None:
self.connection = KinesisConnection()
else:
self.connection = connection
self.shard = self.session.query(models.KinesisShard).filter(
models.KinesisShard.stream==self.stream,
models.KinesisShard.shard_id==self.shard_id
).first()
if not self.shard:
self.shard = models.KinesisShard(
stream=self.stream,
shard_id=self.shard_id
)
class Consumer(object):
def __init__(self, stream, shard_id, session, connection=None, limit=None):
self.stream = stream
self.shard_id = shard_id
self.limit = limit
self.session = session
if connection is None:
self.connection = KinesisConnection()
else:
self.connection = connection
self.shard = self.session.query(models.KinesisShard).filter(
models.KinesisShard.stream==self.stream,
models.KinesisShard.shard_id==self.shard_id
).first()
if not self.shard:
self.shard = models.KinesisShard(
stream=self.stream,
shard_id=self.shard_id
)
def get_current_record(self):
if self.shard.last_record:
return self.shard.last_record
return None
def save_current_record(self, current_record):
self.shard.last_record = current_record
self.session.add(self.shard)
self.session.commit()
def process(self, sleep=True):
stream_desc = self.connection.describe_stream(self.stream)
shard_dict = {
shard['ShardId']: shard
for shard in stream_desc['StreamDescription']['Shards']
}
shard = shard_dict[self.shard_id]
last_record = self.get_current_record()
if last_record is None:
last_record = shard['SequenceNumberRange']['StartingSequenceNumber']
shard_iterator_result = self.connection.get_shard_iterator(
self.stream,
self.shard_id,
'AT_SEQUENCE_NUMBER',
last_record)
else:
shard_iterator_result = self.connection.get_shard_iterator(
self.stream,
self.shard_id,
'AFTER_SEQUENCE_NUMBER',
last_record)
shard_iterator = shard_iterator_result['ShardIterator']
times = 0
processing = True
while True:
records_result = self.connection.get_records(shard_iterator)
records = records_result['Records']
for record in records:
processing = self.process_record(record['Data'])
if processing:
self.save_current_record(record['SequenceNumber'])
else:
break
shard_iterator = records_result['NextShardIterator']
times += 1
if not processing or (self.limit and times > self.limit):
break
if sleep:
time.sleep(1)
def process_record(self, record):
return True
