from __future__ import absolute_import import collections import copy import logging import threading import six from .. import errors as Errors from ..structs import TopicPartition from ..version import __version__ from ..protocol.produce import ProduceRequest log = logging.getLogger(__name__) class Sender(threading.Thread): """ The background thread that handles the sending of produce requests to the Kafka cluster. This thread makes metadata requests to renew its view of the cluster and then sends produce requests to the appropriate nodes. """ _DEFAULT_CONFIG = { 'max_request_size': 1048576, 'acks': 1, 'retries': 0, 'request_timeout_ms': 30000, 'client_id': 'kafka-python-' + __version__, 'api_version': (0, 8, 0), } def __init__(self, client, metadata, accumulator, **configs): super(Sender, self).__init__() self.config = copy.copy(self._DEFAULT_CONFIG) for key in self.config: if key in configs: self.config[key] = configs.pop(key) self.name = self.config['client_id'] + '-network-thread' self._client = client self._accumulator = accumulator self._metadata = client.cluster self._running = True self._force_close = False self._topics_to_add = set() def run(self): """The main run loop for the sender thread.""" log.debug("Starting Kafka producer I/O thread.") # main loop, runs until close is called while self._running: try: self.run_once() except Exception: log.exception("Uncaught error in kafka producer I/O thread") log.debug("Beginning shutdown of Kafka producer I/O thread, sending" " remaining records.") # okay we stopped accepting requests but there may still be # requests in the accumulator or waiting for acknowledgment, # wait until these are completed. while (not self._force_close and (self._accumulator.has_unsent() or self._client.in_flight_request_count() > 0)): try: self.run_once() except Exception: log.exception("Uncaught error in kafka producer I/O thread") if self._force_close: # We need to fail all the incomplete batches and wake up the # threads waiting on the futures. self._accumulator.abort_incomplete_batches() try: self._client.close() except Exception: log.exception("Failed to close network client") log.debug("Shutdown of Kafka producer I/O thread has completed.") def run_once(self): """Run a single iteration of sending.""" while self._topics_to_add: self._client.add_topic(self._topics_to_add.pop()) # get the list of partitions with data ready to send result = self._accumulator.ready(self._metadata) ready_nodes, next_ready_check_delay, unknown_leaders_exist = result # if there are any partitions whose leaders are not known yet, force # metadata update if unknown_leaders_exist: log.debug('Unknown leaders exist, requesting metadata update') self._metadata.request_update() # remove any nodes we aren't ready to send to not_ready_timeout = 999999999 for node in list(ready_nodes): if not self._client.ready(node): log.debug('Node %s not ready; delaying produce of accumulated batch', node) ready_nodes.remove(node) not_ready_timeout = min(not_ready_timeout, self._client.connection_delay(node)) # create produce requests batches_by_node = self._accumulator.drain( self._metadata, ready_nodes, self.config['max_request_size']) expired_batches = self._accumulator.abort_expired_batches( self.config['request_timeout_ms'], self._metadata) requests = self._create_produce_requests(batches_by_node) # If we have any nodes that are ready to send + have sendable data, # poll with 0 timeout so this can immediately loop and try sending more # data. Otherwise, the timeout is determined by nodes that have # partitions with data that isn't yet sendable (e.g. lingering, backing # off). Note that this specifically does not include nodes with # sendable data that aren't ready to send since they would cause busy # looping. poll_timeout_ms = min(next_ready_check_delay * 1000, not_ready_timeout) if ready_nodes: log.debug("Nodes with data ready to send: %s", ready_nodes) # trace log.debug("Created %d produce requests: %s", len(requests), requests) # trace poll_timeout_ms = 0 for node_id, request in six.iteritems(requests): batches = batches_by_node[node_id] log.debug('Sending Produce Request: %r', request) (self._client.send(node_id, request) .add_callback( self._handle_produce_response, batches) .add_errback( self._failed_produce, batches, node_id)) # if some partitions are already ready to be sent, the select time # would be 0; otherwise if some partition already has some data # accumulated but not ready yet, the select time will be the time # difference between now and its linger expiry time; otherwise the # select time will be the time difference between now and the # metadata expiry time self._client.poll(poll_timeout_ms, sleep=True) def initiate_close(self): """Start closing the sender (won't complete until all data is sent).""" self._running = False self._accumulator.close() self.wakeup() def force_close(self): """Closes the sender without sending out any pending messages.""" self._force_close = True self.initiate_close() def add_topic(self, topic): if topic not in self._topics_to_add: self._topics_to_add.add(topic) self.wakeup() def _failed_produce(self, batches, node_id, error): log.debug("Error sending produce request to node %d: %s", node_id, error) # trace for batch in batches: self._complete_batch(batch, error, -1) def _handle_produce_response(self, batches, response): """Handle a produce response.""" # if we have a response, parse it log.debug('Parsing produce response: %r', response) if response: batches_by_partition = dict([(batch.topic_partition, batch) for batch in batches]) for topic, partitions in response.topics: for partition, error_code, offset in partitions: tp = TopicPartition(topic, partition) error = Errors.for_code(error_code) batch = batches_by_partition[tp] self._complete_batch(batch, error, offset) else: # this is the acks = 0 case, just complete all requests for batch in batches: self._complete_batch(batch, None, -1) def _complete_batch(self, batch, error, base_offset): """Complete or retry the given batch of records. Arguments: batch (RecordBatch): The record batch error (Exception): The error (or None if none) base_offset (int): The base offset assigned to the records if successful """ # Standardize no-error to None if error is Errors.NoError: error = None if error is not None and self._can_retry(batch, error): # retry log.warning("Got error produce response on topic-partition %s," " retrying (%d attempts left). Error: %s", batch.topic_partition, self.config['retries'] - batch.attempts - 1, error) self._accumulator.reenqueue(batch) else: if error is Errors.TopicAuthorizationFailedError: error = error(batch.topic_partition.topic) # tell the user the result of their request batch.done(base_offset, error) self._accumulator.deallocate(batch) if getattr(error, 'invalid_metadata', False): self._metadata.request_update() def _can_retry(self, batch, error): """ We can retry a send if the error is transient and the number of attempts taken is fewer than the maximum allowed """ return (batch.attempts < self.config['retries'] and getattr(error, 'retriable', False)) def _create_produce_requests(self, collated): """ Transfer the record batches into a list of produce requests on a per-node basis. Arguments: collated: {node_id: [RecordBatch]} Returns: dict: {node_id: ProduceRequest} (version depends on api_version) """ requests = {} for node_id, batches in six.iteritems(collated): requests[node_id] = self._produce_request( node_id, self.config['acks'], self.config['request_timeout_ms'], batches) return requests def _produce_request(self, node_id, acks, timeout, batches): """Create a produce request from the given record batches. Returns: ProduceRequest (version depends on api_version) """ produce_records_by_partition = collections.defaultdict(dict) for batch in batches: topic = batch.topic_partition.topic partition = batch.topic_partition.partition # TODO: bytearray / memoryview buf = batch.records.buffer() produce_records_by_partition[topic][partition] = buf version = 1 if self.config['api_version'] >= (0, 9) else 0 return ProduceRequest[version]( required_acks=acks, timeout=timeout, topics=[(topic, list(partition_info.items())) for topic, partition_info in six.iteritems(produce_records_by_partition)] ) def wakeup(self): """Wake up the selector associated with this send thread.""" self._client.wakeup()