Merge pull request #1161 from dpkp/issue1036_offset_by_time

Added support for offsets_for_times, beginning_offsets and end_offsets APIs.

1 files changed, 180 insertions, 61 deletions

diff --git a/kafka/consumer/fetcher.py b/kafka/consumer/fetcher.py
index 8db89a1..c0d6075 100644
--- a/kafka/consumer/fetcher.py
+++ b/kafka/consumer/fetcher.py
@@ -14,9 +14,11 @@ from kafka.future import Future
 from kafka.metrics.stats import Avg, Count, Max, Rate
 from kafka.protocol.fetch import FetchRequest
 from kafka.protocol.message import PartialMessage
-from kafka.protocol.offset import OffsetRequest, OffsetResetStrategy
+from kafka.protocol.offset import (
+    OffsetRequest, OffsetResetStrategy, UNKNOWN_OFFSET
+)
 from kafka.serializer import Deserializer
-from kafka.structs import TopicPartition
+from kafka.structs import TopicPartition, OffsetAndTimestamp
 
 log = logging.getLogger(__name__)
 
@@ -48,6 +50,7 @@ class Fetcher(six.Iterator):
         'iterator_refetch_records': 1,  # undocumented -- interface may change
         'metric_group_prefix': 'consumer',
         'api_version': (0, 8, 0),
+        'retry_backoff_ms': 100
     }
 
     def __init__(self, client, subscriptions, metrics, **configs):
@@ -180,6 +183,31 @@ class Fetcher(six.Iterator):
                           " offset %s", tp, committed)
                 self._subscriptions.seek(tp, committed)
 
+    def get_offsets_by_times(self, timestamps, timeout_ms):
+        offsets = self._retrieve_offsets(timestamps, timeout_ms)
+        for tp in timestamps:
+            if tp not in offsets:
+                offsets[tp] = None
+            else:
+                offset, timestamp = offsets[tp]
+                offsets[tp] = OffsetAndTimestamp(offset, timestamp)
+        return offsets
+
+    def beginning_offsets(self, partitions, timeout_ms):
+        return self.beginning_or_end_offset(
+            partitions, OffsetResetStrategy.EARLIEST, timeout_ms)
+
+    def end_offsets(self, partitions, timeout_ms):
+        return self.beginning_or_end_offset(
+            partitions, OffsetResetStrategy.LATEST, timeout_ms)
+
+    def beginning_or_end_offset(self, partitions, timestamp, timeout_ms):
+        timestamps = dict([(tp, timestamp) for tp in partitions])
+        offsets = self._retrieve_offsets(timestamps, timeout_ms)
+        for tp in timestamps:
+            offsets[tp] = offsets[tp][0]
+        return offsets
+
     def _reset_offset(self, partition):
         """Reset offsets for the given partition using the offset reset strategy.
 
@@ -199,40 +227,64 @@ class Fetcher(six.Iterator):
 
         log.debug("Resetting offset for partition %s to %s offset.",
                   partition, strategy)
-        offset = self._offset(partition, timestamp)
+        offsets = self._retrieve_offsets({partition: timestamp})
+        if partition not in offsets:
+            raise NoOffsetForPartitionError(partition)
+        offset = offsets[partition][0]
 
         # we might lose the assignment while fetching the offset,
         # so check it is still active
         if self._subscriptions.is_assigned(partition):
             self._subscriptions.seek(partition, offset)
 
-    def _offset(self, partition, timestamp):
-        """Fetch a single offset before the given timestamp for the partition.
+    def _retrieve_offsets(self, timestamps, timeout_ms=float("inf")):
+        """Fetch offset for each partition passed in ``timestamps`` map.
 
-        Blocks until offset is obtained, or a non-retriable exception is raised
+        Blocks until offsets are obtained, a non-retriable exception is raised
+        or ``timeout_ms`` passed.
 
         Arguments:
-            partition The partition that needs fetching offset.
-            timestamp (int): timestamp for fetching offset. -1 for the latest
-                available, -2 for the earliest available. Otherwise timestamp
-                is treated as epoch seconds.
+            timestamps: {TopicPartition: int} dict with timestamps to fetch
+                offsets by. -1 for the latest available, -2 for the earliest
+                available. Otherwise timestamp is treated as epoch miliseconds.
 
         Returns:
-            int: message offset
+            {TopicPartition: (int, int)}: Mapping of partition to
+                retrieved offset and timestamp. If offset does not exist for
+                the provided timestamp, that partition will be missing from
+                this mapping.
         """
-        while True:
-            future = self._send_offset_request(partition, timestamp)
-            self._client.poll(future=future)
+        if not timestamps:
+            return {}
+
+        start_time = time.time()
+        remaining_ms = timeout_ms
+        while remaining_ms > 0:
+            future = self._send_offset_requests(timestamps)
+            self._client.poll(future=future, timeout_ms=remaining_ms)
 
             if future.succeeded():
                 return future.value
-
             if not future.retriable():
                 raise future.exception  # pylint: disable-msg=raising-bad-type
 
+            elapsed_ms = (time.time() - start_time) * 1000
+            remaining_ms = timeout_ms - elapsed_ms
+            if remaining_ms < 0:
+                break
+
             if future.exception.invalid_metadata:
                 refresh_future = self._client.cluster.request_update()
-                self._client.poll(future=refresh_future, sleep=True)
+                self._client.poll(
+                    future=refresh_future, sleep=True, timeout_ms=remaining_ms)
+            else:
+                time.sleep(self.config['retry_backoff_ms'] / 1000.0)
+
+            elapsed_ms = (time.time() - start_time) * 1000
+            remaining_ms = timeout_ms - elapsed_ms
+
+        raise Errors.KafkaTimeoutError(
+            "Failed to get offsets by timestamps in %s ms" % timeout_ms)
 
     def _raise_if_offset_out_of_range(self):
         """Check FetchResponses for offset out of range.
@@ -576,73 +628,140 @@ class Fetcher(six.Iterator):
             return f.deserialize(topic, bytes_)
         return f(bytes_)
 
-    def _send_offset_request(self, partition, timestamp):
-        """Fetch a single offset before the given timestamp for the partition.
+    def _send_offset_requests(self, timestamps):
+        """Fetch offsets for each partition in timestamps dict. This may send
+        request to multiple nodes, based on who is Leader for partition.
 
         Arguments:
-            partition (TopicPartition): partition that needs fetching offset
-            timestamp (int): timestamp for fetching offset
+            timestamps (dict): {TopicPartition: int} mapping of fetching
+                timestamps.
 
         Returns:
-            Future: resolves to the corresponding offset
+            Future: resolves to a mapping of retrieved offsets
         """
-        node_id = self._client.cluster.leader_for_partition(partition)
-        if node_id is None:
-            log.debug("Partition %s is unknown for fetching offset,"
-                      " wait for metadata refresh", partition)
-            return Future().failure(Errors.StaleMetadata(partition))
-        elif node_id == -1:
-            log.debug("Leader for partition %s unavailable for fetching offset,"
-                      " wait for metadata refresh", partition)
-            return Future().failure(Errors.LeaderNotAvailableError(partition))
-
-        request = OffsetRequest[0](
-            -1, [(partition.topic, [(partition.partition, timestamp, 1)])]
-        )
+        timestamps_by_node = collections.defaultdict(dict)
+        for partition, timestamp in six.iteritems(timestamps):
+            node_id = self._client.cluster.leader_for_partition(partition)
+            if node_id is None:
+                self._client.add_topic(partition.topic)
+                log.debug("Partition %s is unknown for fetching offset,"
+                          " wait for metadata refresh", partition)
+                return Future().failure(Errors.StaleMetadata(partition))
+            elif node_id == -1:
+                log.debug("Leader for partition %s unavailable for fetching "
+                          "offset, wait for metadata refresh", partition)
+                return Future().failure(
+                    Errors.LeaderNotAvailableError(partition))
+            else:
+                timestamps_by_node[node_id][partition] = timestamp
+
+        # Aggregate results until we have all
+        list_offsets_future = Future()
+        responses = []
+        node_count = len(timestamps_by_node)
+
+        def on_success(value):
+            responses.append(value)
+            if len(responses) == node_count:
+                offsets = {}
+                for r in responses:
+                    offsets.update(r)
+                list_offsets_future.success(offsets)
+
+        def on_fail(err):
+            if not list_offsets_future.is_done:
+                list_offsets_future.failure(err)
+
+        for node_id, timestamps in six.iteritems(timestamps_by_node):
+            _f = self._send_offset_request(node_id, timestamps)
+            _f.add_callback(on_success)
+            _f.add_errback(on_fail)
+        return list_offsets_future
+
+    def _send_offset_request(self, node_id, timestamps):
+        by_topic = collections.defaultdict(list)
+        for tp, timestamp in six.iteritems(timestamps):
+            if self.config['api_version'] >= (0, 10, 1):
+                data = (tp.partition, timestamp)
+            else:
+                data = (tp.partition, timestamp, 1)
+            by_topic[tp.topic].append(data)
+
+        if self.config['api_version'] >= (0, 10, 1):
+            request = OffsetRequest[1](-1, list(six.iteritems(by_topic)))
+        else:
+            request = OffsetRequest[0](-1, list(six.iteritems(by_topic)))
+
         # Client returns a future that only fails on network issues
         # so create a separate future and attach a callback to update it
         # based on response error codes
         future = Future()
+
         _f = self._client.send(node_id, request)
-        _f.add_callback(self._handle_offset_response, partition, future)
+        _f.add_callback(self._handle_offset_response, future)
         _f.add_errback(lambda e: future.failure(e))
         return future
 
-    def _handle_offset_response(self, partition, future, response):
+    def _handle_offset_response(self, future, response):
         """Callback for the response of the list offset call above.
 
         Arguments:
-            partition (TopicPartition): The partition that was fetched
             future (Future): the future to update based on response
             response (OffsetResponse): response from the server
 
         Raises:
             AssertionError: if response does not match partition
         """
-        topic, partition_info = response.topics[0]
-        assert len(response.topics) == 1 and len(partition_info) == 1, (
-            'OffsetResponse should only be for a single topic-partition')
-
-        part, error_code, offsets = partition_info[0]
-        assert topic == partition.topic and part == partition.partition, (
-            'OffsetResponse partition does not match OffsetRequest partition')
-
-        error_type = Errors.for_code(error_code)
-        if error_type is Errors.NoError:
-            assert len(offsets) == 1, 'Expected OffsetResponse with one offset'
-            offset = offsets[0]
-            log.debug("Fetched offset %d for partition %s", offset, partition)
-            future.success(offset)
-        elif error_type in (Errors.NotLeaderForPartitionError,
-                            Errors.UnknownTopicOrPartitionError):
-            log.debug("Attempt to fetch offsets for partition %s failed due"
-                      " to obsolete leadership information, retrying.",
-                      partition)
-            future.failure(error_type(partition))
-        else:
-            log.warning("Attempt to fetch offsets for partition %s failed due to:"
-                        " %s", partition, error_type)
-            future.failure(error_type(partition))
+        timestamp_offset_map = {}
+        for topic, part_data in response.topics:
+            for partition_info in part_data:
+                partition, error_code = partition_info[:2]
+                partition = TopicPartition(topic, partition)
+                error_type = Errors.for_code(error_code)
+                if error_type is Errors.NoError:
+                    if response.API_VERSION == 0:
+                        offsets = partition_info[2]
+                        assert len(offsets) <= 1, 'Expected OffsetResponse with one offset'
+                        if not offsets:
+                            offset = UNKNOWN_OFFSET
+                        else:
+                            offset = offsets[0]
+                        log.debug("Handling v0 ListOffsetResponse response for %s. "
+                                  "Fetched offset %s", partition, offset)
+                        if offset != UNKNOWN_OFFSET:
+                            timestamp_offset_map[partition] = (offset, None)
+                    else:
+                        timestamp, offset = partition_info[2:]
+                        log.debug("Handling ListOffsetResponse response for %s. "
+                                  "Fetched offset %s, timestamp %s",
+                                  partition, offset, timestamp)
+                        if offset != UNKNOWN_OFFSET:
+                            timestamp_offset_map[partition] = (offset, timestamp)
+                elif error_type is Errors.UnsupportedForMessageFormatError:
+                    # The message format on the broker side is before 0.10.0,
+                    # we simply put None in the response.
+                    log.debug("Cannot search by timestamp for partition %s because the"
+                              " message format version is before 0.10.0", partition)
+                elif error_type is Errors.NotLeaderForPartitionError:
+                    log.debug("Attempt to fetch offsets for partition %s failed due"
+                              " to obsolete leadership information, retrying.",
+                              partition)
+                    future.failure(error_type(partition))
+                    return
+                elif error_type is Errors.UnknownTopicOrPartitionError:
+                    log.warn("Received unknown topic or partition error in ListOffset "
+                             "request for partition %s. The topic/partition " +
+                             "may not exist or the user may not have Describe access "
+                             "to it.", partition)
+                    future.failure(error_type(partition))
+                    return
+                else:
+                    log.warning("Attempt to fetch offsets for partition %s failed due to:"
+                                " %s", partition, error_type)
+                    future.failure(error_type(partition))
+                    return
+        if not future.is_done:
+            future.success(timestamp_offset_map)
 
     def _fetchable_partitions(self):
         fetchable = self._subscriptions.fetchable_partitions()