"""Partition assignor."""
import socket
import zlib
from collections import defaultdict
from typing import Iterable, List, Mapping, MutableMapping, Sequence, Set, cast
from aiokafka.cluster import ClusterMetadata
from aiokafka.coordinator.assignors.abstract import AbstractPartitionAssignor
from aiokafka.coordinator.protocol import (
ConsumerProtocolMemberAssignment,
ConsumerProtocolMemberMetadata,
)
from mode import get_logger
from yarl import URL
from faust.types.app import AppT
from faust.types.assignor import (
HostToPartitionMap,
PartitionAssignorT,
TopicToPartitionMap,
)
from faust.types.tables import TableManagerT
from faust.types.tuples import TP
from .client_assignment import ClientAssignment, ClientMetadata
from .cluster_assignment import ClusterAssignment
from .copartitioned_assignor import CopartitionedAssignor
__all__ = [
"MemberAssignmentMapping",
"MemberMetadataMapping",
"MemberSubscriptionMapping",
"ClientMetadataMapping",
"ClientAssignmentMapping",
"CopartitionedGroups",
"PartitionAssignor",
]
MemberAssignmentMapping = MutableMapping[str, ConsumerProtocolMemberAssignment]
MemberMetadataMapping = MutableMapping[str, ConsumerProtocolMemberMetadata]
MemberSubscriptionMapping = MutableMapping[str, List[str]]
ClientMetadataMapping = MutableMapping[str, ClientMetadata]
ClientAssignmentMapping = MutableMapping[str, ClientAssignment]
CopartitionedGroups = MutableMapping[int, Iterable[Set[str]]]
logger = get_logger(__name__)
[docs]class PartitionAssignor(AbstractPartitionAssignor, PartitionAssignorT): # type: ignore
"""PartitionAssignor handles internal topic creation.
Further, this assignor needs to be sticky and potentially redundant
In addition, it tracks external topic assignments as well (to support topic routes)
Notes:
Interface copied from :mod:`kafka.coordinator.assignors.abstract`.
"""
_assignment: ClientAssignment
_table_manager: TableManagerT
_member_urls: MutableMapping[str, str]
_changelog_distribution: HostToPartitionMap
_external_topic_distribution: HostToPartitionMap
_active_tps: Set[TP]
_standby_tps: Set[TP]
_tps_url: MutableMapping[TP, str]
_external_tps_url: MutableMapping[TP, str]
_topic_groups: MutableMapping[str, int]
def __init__(self, app: AppT, replicas: int = 0) -> None:
AbstractPartitionAssignor.__init__(self)
self.app = app
self._table_manager = self.app.tables
self._assignment = ClientAssignment(actives={}, standbys={})
self._changelog_distribution = {}
self._external_topic_distribution = {}
self.replicas = replicas
self._member_urls = {}
self._tps_url = {}
self._external_tps_url = {}
self._active_tps = set()
self._standby_tps = set()
self._topic_groups = {}
[docs] def group_for_topic(self, topic: str) -> int:
return self._topic_groups[topic]
@property
def changelog_distribution(self) -> HostToPartitionMap:
return self._changelog_distribution
@changelog_distribution.setter
def changelog_distribution(self, value: HostToPartitionMap) -> None:
self._changelog_distribution = value
self._tps_url = {
TP(topic, partition): url
for url, tps in self._changelog_distribution.items()
for topic, partitions in tps.items()
for partition in partitions
}
@property
def external_topic_distribution(self) -> HostToPartitionMap:
return self._external_topic_distribution
@external_topic_distribution.setter
def external_topic_distribution(self, value: HostToPartitionMap) -> None:
self._external_topic_distribution = value
self._external_tps_url = {
TP(topic, partition): url
for url, tps in self._external_topic_distribution.items()
for topic, partitions in tps.items()
for partition in partitions
}
@property
def _metadata(self) -> ClientMetadata:
return ClientMetadata(
assignment=self._assignment,
url=str(self._url),
changelog_distribution=self.changelog_distribution,
external_topic_distribution=self.external_topic_distribution,
topic_groups=self._topic_groups,
)
@property
def _url(self) -> URL:
return self.app.conf.canonical_url
[docs] def on_assignment(self, assignment: ConsumerProtocolMemberMetadata) -> None:
metadata = cast(
ClientMetadata, ClientMetadata.loads(self._decompress(assignment.user_data))
)
self._assignment = metadata.assignment
self._topic_groups = dict(metadata.topic_groups)
self._active_tps = self._assignment.active_tps
self._standby_tps = self._assignment.standby_tps
self.changelog_distribution = metadata.changelog_distribution
self.external_topic_distribution = metadata.external_topic_distribution
a = sorted(assignment.assignment)
b = sorted(self._assignment.kafka_protocol_assignment(self._table_manager))
assert a == b, f"{a!r} != {b!r}"
assert metadata.url == str(self._url)
@classmethod
def _group_co_subscribed(
cls,
topics: Set[str],
subscriptions: MemberSubscriptionMapping,
) -> Iterable[Set[str]]:
topic_subscriptions: MutableMapping[str, Set[str]] = defaultdict(set)
for client, subscription in subscriptions.items():
for topic in subscription:
topic_subscriptions[topic].add(client)
co_subscribed: MutableMapping[Sequence[str], Set[str]] = defaultdict(set)
for topic in topics:
clients = topic_subscriptions[topic]
assert clients, "Subscribed clients for topic cannot be empty"
co_subscribed[tuple(clients)].add(topic)
return co_subscribed.values()
@classmethod
def _get_copartitioned_groups(
cls,
topics: Set[str],
cluster: ClusterMetadata,
subscriptions: MemberSubscriptionMapping,
) -> CopartitionedGroups:
topics_by_partitions: MutableMapping[int, Set] = defaultdict(set)
for topic in topics:
num_partitions = len(cluster.partitions_for_topic(topic) or set())
if num_partitions == 0:
logger.warning("Ignoring missing topic: %r", topic)
continue
topics_by_partitions[num_partitions].add(topic)
# We group copartitioned topics by subscribed clients such that
# a group of co-subscribed topics with the same number of partitions
# are copartitioned
copart_grouped = {
num_partitions: cls._group_co_subscribed(topics, subscriptions)
for num_partitions, topics in topics_by_partitions.items()
}
return copart_grouped
@classmethod
def _get_client_metadata(
cls, metadata: ConsumerProtocolMemberMetadata
) -> ClientMetadata:
client_metadata = ClientMetadata.loads(metadata.user_data)
return cast(ClientMetadata, client_metadata)
def _update_member_urls(self, clients_metadata: ClientMetadataMapping) -> None:
self._member_urls = {
member_id: client_metadata.url
for member_id, client_metadata in clients_metadata.items()
}
[docs] def assign(
self, cluster: ClusterMetadata, member_metadata: MemberMetadataMapping
) -> MemberAssignmentMapping:
if self.app.tracer:
return self._trace_assign(cluster, member_metadata)
else:
return self._assign(cluster, member_metadata)
def _trace_assign(
self, cluster: ClusterMetadata, member_metadata: MemberMetadataMapping
) -> MemberAssignmentMapping:
assert self.app.tracer is not None
span = self.app.tracer.get_tracer("_faust").start_span(
operation_name="coordinator_assignment",
tags={"hostname": socket.gethostname()},
)
with span:
assignment = self._assign(cluster, member_metadata)
self.app._span_add_default_tags(span)
span.set_tag("assignment", assignment)
return assignment
def _assign(
self, cluster: ClusterMetadata, member_metadata: MemberMetadataMapping
) -> MemberAssignmentMapping:
sensor_state = self.app.sensors.on_assignment_start(self)
try:
assignment = self._perform_assignment(cluster, member_metadata)
except MemoryError:
raise
except Exception as exc:
self.app.sensors.on_assignment_error(self, sensor_state, exc)
raise
else:
self.app.sensors.on_assignment_completed(self, sensor_state)
return assignment
def _perform_assignment(
self, cluster: ClusterMetadata, member_metadata: MemberMetadataMapping
) -> MemberAssignmentMapping:
cluster_assgn = ClusterAssignment()
clients_metadata = {
member_id: self._get_client_metadata(metadata)
for member_id, metadata in member_metadata.items()
}
subscriptions = {
member_id: cast(List[str], metadata.subscription)
for member_id, metadata in member_metadata.items()
}
for member_id in member_metadata:
cluster_assgn.add_client(
member_id, subscriptions[member_id], clients_metadata[member_id]
)
topics = cluster_assgn.topics()
copartitioned_groups = self._get_copartitioned_groups(
topics, cluster, subscriptions
)
self._update_member_urls(clients_metadata)
# Initialize fresh assignment
assignments: ClientAssignmentMapping = {
member_id: ClientAssignment(actives={}, standbys={})
for member_id in member_metadata
}
topic_to_group_id = {}
partitions_by_topic = {}
for group_id, (num_partitions, topic_groups) in enumerate(
sorted(copartitioned_groups.items())
):
for topics in topic_groups:
for topic in topics:
topic_to_group_id[topic] = group_id
partitions_by_topic[topic] = num_partitions
assert len(topics) > 0 and num_partitions > 0
# Get assignment for unique copartitioned group
assgn = cluster_assgn.copartitioned_assignments(topics)
assignor = CopartitionedAssignor(
topics=topics,
cluster_asgn=assgn,
num_partitions=num_partitions,
replicas=self.replicas,
)
# Update client assignments for copartitioned group
for client, copart_assn in assignor.get_assignment().items():
assignments[client].add_copartitioned_assignment(copart_assn)
# Add all changelogs of global tables as standby for all members
assignments = self._global_table_standby_assignments(
assignments, partitions_by_topic
)
changelog_distribution = self._get_changelog_distribution(assignments)
external_topic_distribution = self._get_external_topic_distribution(assignments)
res = self._protocol_assignments(
assignments,
changelog_distribution,
external_topic_distribution,
topic_to_group_id,
)
return res
def _global_table_standby_assignments(
self,
assignments: ClientAssignmentMapping,
partitions_by_topic: Mapping[str, int],
) -> ClientAssignmentMapping:
# Ensures all members have access to all changelog partitions
# as standbys, if not already as actives
for table in self._table_manager.data.values():
# Add changelog standbys only if global table
if table.is_global:
changelog_topic_name = table._changelog_topic_name()
num_partitions = partitions_by_topic[changelog_topic_name]
assert num_partitions is not None
all_partitions = set(range(0, num_partitions))
for assignment in assignments.values():
active_partitions = set(
assignment.actives.get(changelog_topic_name, [])
)
# if we use_partitioner it could happen that we write in Worker A
# to a partitions which is not active in Worker A but active in
# Worker B. To let Worker B consume the update we have to have
# all_partitions as standbys as well.
# A similar situation is happening if Global tables are shared
# over multiple consumer groups. Consumer group A could write to
# the table and consumer group B, C, D only consuming. With the
# synchronize_all_active_partitions flag it's possible to have
# shared state over multiple consumer groups.
if table.synchronize_all_active_partitions or table.use_partitioner:
standby_partitions = all_partitions
else: # Only add those partitions as standby which aren't active
standby_partitions = all_partitions - active_partitions
assignment.standbys[changelog_topic_name] = list(standby_partitions)
# We add all_partitions as active so they are recovered
# in the beginning.
assignment.actives[changelog_topic_name] = list(all_partitions)
return assignments
def _protocol_assignments(
self,
assignments: ClientAssignmentMapping,
cl_distribution: HostToPartitionMap,
tp_distribution: HostToPartitionMap,
topic_groups: Mapping[str, int],
) -> MemberAssignmentMapping:
return {
client: ConsumerProtocolMemberAssignment(
self.version,
sorted(assignment.kafka_protocol_assignment(self._table_manager)),
self._compress(
ClientMetadata(
assignment=assignment,
url=self._member_urls[client],
changelog_distribution=cl_distribution,
external_topic_distribution=tp_distribution,
topic_groups=topic_groups,
).dumps(),
),
)
for client, assignment in assignments.items()
}
@classmethod
def _compress(cls, raw: bytes) -> bytes:
return zlib.compress(raw)
@classmethod
def _decompress(cls, compressed: bytes) -> bytes:
return zlib.decompress(compressed)
@classmethod
def _topics_filtered(
cls, assignment: TopicToPartitionMap, topics: Set[str]
) -> TopicToPartitionMap:
return {
topic: partitions
for topic, partitions in assignment.items()
if topic in topics
}
@classmethod
def _non_table_topics_filtered(
cls, assignment: TopicToPartitionMap, topics: Set[str]
) -> TopicToPartitionMap:
return {
topic: partitions
for topic, partitions in assignment.items()
if topic not in topics
}
def _get_changelog_distribution(
self, assignments: ClientAssignmentMapping
) -> HostToPartitionMap:
topics = self._table_manager.changelog_topics
return {
self._member_urls[client]: self._topics_filtered(assignment.actives, topics)
for client, assignment in assignments.items()
}
def _get_external_topic_distribution(
self, assignments: ClientAssignmentMapping
) -> HostToPartitionMap:
topics = self._table_manager.changelog_topics
return {
self._member_urls[client]: self._non_table_topics_filtered(
assignment.actives, topics
)
for client, assignment in assignments.items()
}
@property
def name(self) -> str:
return "faust"
@property
def version(self) -> int:
return 4
[docs] def assigned_standbys(self) -> Set[TP]:
return {
TP(topic, partition)
for topic, partitions in self._assignment.standbys.items()
for partition in partitions
}
[docs] def assigned_actives(self) -> Set[TP]:
return {
TP(topic, partition)
for topic, partitions in self._assignment.actives.items()
for partition in partitions
}
[docs] def key_store(self, topic: str, key: bytes) -> URL:
return URL(self._tps_url[self.app.producer.key_partition(topic, key)])
[docs] def external_key_store(self, topic: str, key: bytes) -> URL:
return URL(self._external_tps_url[self.app.producer.key_partition(topic, key)])
[docs] def is_active(self, tp: TP) -> bool:
return tp in self._active_tps
[docs] def is_standby(self, tp: TP) -> bool:
return tp in self._standby_tps
