KafkaRoute

faststream.kafka.broker.router.KafkaRoute

KafkaRoute(
    call,
    *topics,
    publishers=(),
    batch=False,
    group_id=None,
    key_deserializer=None,
    value_deserializer=None,
    fetch_max_bytes=50 * 1024 * 1024,
    fetch_min_bytes=1,
    fetch_max_wait_ms=500,
    max_partition_fetch_bytes=1 * 1024 * 1024,
    auto_offset_reset="latest",
    auto_commit=EMPTY,
    auto_commit_interval_ms=5 * 1000,
    check_crcs=True,
    partition_assignment_strategy=(
        RoundRobinPartitionAssignor,
    ),
    max_poll_interval_ms=5 * 60 * 1000,
    rebalance_timeout_ms=None,
    session_timeout_ms=10 * 1000,
    heartbeat_interval_ms=3 * 1000,
    consumer_timeout_ms=200,
    max_poll_records=None,
    exclude_internal_topics=True,
    isolation_level="read_uncommitted",
    batch_timeout_ms=200,
    max_records=None,
    listener=None,
    pattern=None,
    partitions=(),
    dependencies=(),
    parser=None,
    decoder=None,
    middlewares=(),
    no_ack=EMPTY,
    ack_policy=EMPTY,
    no_reply=False,
    title=None,
    description=None,
    include_in_schema=True,
    max_workers=None,
)

Bases: SubscriberRoute

Class to store delayed KafkaBroker subscriber registration.

Initialize KafkaRoute.

PARAMETER	DESCRIPTION
call	Message handler function to wrap the same with @broker.subscriber(...) way. TYPE: Callable[..., SendableMessage] | Callable[..., Awaitable[SendableMessage]]
*topics	"Kafka topics to consume messages from. TYPE: str DEFAULT: ()
publishers	Kafka publishers to broadcast the handler result. TYPE: Iterable[KafkaPublisher] DEFAULT: ()
batch	Whether to consume messages in batches or not. TYPE: bool DEFAULT: False
group_id	Name of the consumer group to join for dynamic partition assignment (if enabled), and to use for fetching and committing offsets. If None, auto-partition assignment (via group coordinator) and offset commits are disabled. TYPE: str | None DEFAULT: None
key_deserializer	Any callable that takes a raw message `bytes` key and returns a deserialized one. TYPE: Callable[[bytes], Any] | None DEFAULT: None
value_deserializer	Any callable that takes a raw message bytes value and returns a deserialized value. TYPE: Callable[[bytes], Any] | None DEFAULT: None
fetch_max_bytes	The maximum amount of data the server should return for a fetch request. This is not an absolute maximum, if the first message in the first non-empty partition of the fetch is larger than this value, the message will still be returned to ensure that the consumer can make progress. NOTE: consumer performs fetches to multiple brokers in parallel so memory usage will depend on the number of brokers containing partitions for the topic. TYPE: int DEFAULT: 50 * 1024 * 1024
fetch_min_bytes	Minimum amount of data the server should return for a fetch request, otherwise wait up to fetch_max_wait_ms for more data to accumulate. TYPE: int DEFAULT: 1
fetch_max_wait_ms	The maximum amount of time in milliseconds the server will block before answering the fetch request if there isn't sufficient data to immediately satisfy the requirement given by fetch_min_bytes. TYPE: int DEFAULT: 500
max_partition_fetch_bytes	The maximum amount of data per-partition the server will return. The maximum total memory used for a request = #partitions * max_partition_fetch_bytes. This size must be at least as large as the maximum message size the server allows or else it is possible for the producer to send messages larger than the consumer can fetch. If that happens, the consumer can get stuck trying to fetch a large message on a certain partition. TYPE: int DEFAULT: 1 * 1024 * 1024
auto_offset_reset	A policy for resetting offsets on OffsetOutOfRangeError errors: earliest will move to the oldest available message latest will move to the most recent none will raise an exception so you can handle this case TYPE: Literal['latest', 'earliest', 'none'] DEFAULT: 'latest'
auto_commit	If True the consumer's offset will be periodically committed in the background. TYPE: bool DEFAULT: EMPTY
auto_commit_interval_ms	Milliseconds between automatic offset commits, if auto_commit is True. TYPE: int DEFAULT: 5 * 1000
check_crcs	Automatically check the CRC32 of the records consumed. This ensures no on-the-wire or on-disk corruption to the messages occurred. This check adds some overhead, so it may be disabled in cases seeking extreme performance. TYPE: bool DEFAULT: True
partition_assignment_strategy	List of objects to use to distribute partition ownership amongst consumer instances when group management is used. This preference is implicit in the order of the strategies in the list. When assignment strategy changes: to support a change to the assignment strategy, new versions must enable support both for the old assignment strategy and the new one. The coordinator will choose the old assignment strategy until all members have been updated. Then it will choose the new strategy. TYPE: Sequence[AbstractPartitionAssignor] DEFAULT: (RoundRobinPartitionAssignor,)
max_poll_interval_ms	Maximum allowed time between calls to consume messages in batches. If this interval is exceeded the consumer is considered failed and the group will rebalance in order to reassign the partitions to another consumer group member. If API methods block waiting for messages, that time does not count against this timeout. TYPE: int DEFAULT: 5 * 60 * 1000
rebalance_timeout_ms	The maximum time server will wait for this consumer to rejoin the group in a case of rebalance. In Java client this behaviour is bound to max.poll.interval.ms configuration, but as aiokafka will rejoin the group in the background, we decouple this setting to allow finer tuning by users that use ConsumerRebalanceListener to delay rebalacing. Defaults to session_timeout_ms TYPE: int | None DEFAULT: None
session_timeout_ms	Client group session and failure detection timeout. The consumer sends periodic heartbeats (heartbeat.interval.ms) to indicate its liveness to the broker. If no hearts are received by the broker for a group member within the session timeout, the broker will remove the consumer from the group and trigger a rebalance. The allowed range is configured with the broker configuration properties group.min.session.timeout.ms and group.max.session.timeout.ms. TYPE: int DEFAULT: 10 * 1000
heartbeat_interval_ms	The expected time in milliseconds between heartbeats to the consumer coordinator when using Kafka's group management feature. Heartbeats are used to ensure that the consumer's session stays active and to facilitate rebalancing when new consumers join or leave the group. The value must be set lower than session_timeout_ms, but typically should be set no higher than 1/3 of that value. It can be adjusted even lower to control the expected time for normal rebalances. TYPE: int DEFAULT: 3 * 1000
consumer_timeout_ms	Maximum wait timeout for background fetching routine. Mostly defines how fast the system will see rebalance and request new data for new partitions. TYPE: int DEFAULT: 200
max_poll_records	The maximum number of records returned in a single call by batch consumer. Has no limit by default. TYPE: int | None DEFAULT: None
exclude_internal_topics	Whether records from internal topics (such as offsets) should be exposed to the consumer. If set to True the only way to receive records from an internal topic is subscribing to it. TYPE: bool DEFAULT: True
isolation_level	Controls how to read messages written transactionally. read_committed, batch consumer will only return transactional messages which have been committed. read_uncommitted (the default), batch consumer will return all messages, even transactional messages which have been aborted. Non-transactional messages will be returned unconditionally in either mode. Messages will always be returned in offset order. Hence, in read_committed mode, batch consumer will only return messages up to the last stable offset (ALSO), which is the one less than the offset of the first open transaction. In particular any messages appearing after messages belonging to ongoing transactions will be withheld until the relevant transaction has been completed. As a result, read_committed consumers will not be able to read up to the high watermark when there are in flight transactions. Further, when in read_committed the seek_to_end method will return the ALSO. See method docs below. TYPE: Literal['read_uncommitted', 'read_committed'] DEFAULT: 'read_uncommitted'
batch_timeout_ms	Milliseconds spent waiting if data is not available in the buffer. If 0, returns immediately with any records that are available currently in the buffer, else returns empty. TYPE: int DEFAULT: 200
max_records	Number of messages to consume as one batch. TYPE: int | None DEFAULT: None
listener	Optionally include listener callback, which will be called before and after each rebalance operation. As part of group management, the consumer will keep track of the list of consumers that belong to a particular group and will trigger a rebalance operation if one of the following events trigger: Number of partitions change for any of the subscribed topics Topic is created or deleted An existing member of the consumer group dies A new member is added to the consumer group When any of these events are triggered, the provided listener will be invoked first to indicate that the consumer's assignment has been revoked, and then again when the new assignment has been received. Note that this listener will immediately override any listener set in a previous call to subscribe. It is guaranteed, however, that the partitions revoked/assigned through this interface are from topics subscribed in this call. TYPE: Optional[ConsumerRebalanceListener] DEFAULT: None
pattern	Pattern to match available topics. You must provide either topics or pattern, but not both. TYPE: str | None DEFAULT: None
partitions	A topic and partition tuple. You can't use 'topics' and 'partitions' in the same time. TYPE: Iterable[TopicPartition] | None DEFAULT: ()
dependencies	Dependencies list ([Dependant(),]) to apply to the subscriber. TYPE: Iterable[Dependant] DEFAULT: ()
parser	Parser to map original ConsumerRecord object to FastStream one. TYPE: Optional[CustomCallable] DEFAULT: None
decoder	Function to decode FastStream msg bytes body to python objects. TYPE: Optional[CustomCallable] DEFAULT: None
middlewares	Subscriber middlewares to wrap incoming message processing. TYPE: Sequence[SubscriberMiddleware[Any]] DEFAULT: ()
no_ack	Whether to disable FastStream auto acknowledgement logic or not. TYPE: bool DEFAULT: EMPTY
ack_policy	AckPolicy = EMPTY, TYPE: AckPolicy DEFAULT: EMPTY
no_reply	Whether to disable FastStream RPC and Reply To auto responses or not. TYPE: bool DEFAULT: False
title	AsyncAPI subscriber object title. TYPE: str | None DEFAULT: None
description	AsyncAPI subscriber object description. Uses decorated docstring as default. TYPE: str | None DEFAULT: None
include_in_schema	Whetever to include operation in AsyncAPI schema or not. TYPE: bool DEFAULT: True
max_workers	Number of workers to process messages concurrently. TYPE: int | None DEFAULT: None

Source code in faststream/kafka/broker/router.py

def __init__(
    self,
    call: Callable[..., "SendableMessage"]
    | Callable[..., Awaitable["SendableMessage"]],
    *topics: str,
    publishers: Iterable[KafkaPublisher] = (),
    batch: bool = False,
    group_id: str | None = None,
    key_deserializer: Callable[[bytes], Any] | None = None,
    value_deserializer: Callable[[bytes], Any] | None = None,
    fetch_max_bytes: int = 50 * 1024 * 1024,
    fetch_min_bytes: int = 1,
    fetch_max_wait_ms: int = 500,
    max_partition_fetch_bytes: int = 1 * 1024 * 1024,
    auto_offset_reset: Literal["latest", "earliest", "none"] = "latest",
    auto_commit: Annotated[
        bool,
        deprecated(
            "This option is deprecated and will be removed in 0.7.0 release. "
            "Please, use `ack_policy=AckPolicy.ACK_FIRST` instead."
        ),
    ] = EMPTY,
    auto_commit_interval_ms: int = 5 * 1000,
    check_crcs: bool = True,
    partition_assignment_strategy: Sequence["AbstractPartitionAssignor"] = (
        RoundRobinPartitionAssignor,
    ),
    max_poll_interval_ms: int = 5 * 60 * 1000,
    rebalance_timeout_ms: int | None = None,
    session_timeout_ms: int = 10 * 1000,
    heartbeat_interval_ms: int = 3 * 1000,
    consumer_timeout_ms: int = 200,
    max_poll_records: int | None = None,
    exclude_internal_topics: bool = True,
    isolation_level: Literal[
        "read_uncommitted", "read_committed"
    ] = "read_uncommitted",
    batch_timeout_ms: int = 200,
    max_records: int | None = None,
    listener: Optional["ConsumerRebalanceListener"] = None,
    pattern: str | None = None,
    partitions: Iterable["TopicPartition"] | None = (),
    # broker args
    dependencies: Iterable["Dependant"] = (),
    parser: Optional["CustomCallable"] = None,
    decoder: Optional["CustomCallable"] = None,
    middlewares: Annotated[
        Sequence["SubscriberMiddleware[Any]"],
        deprecated(
            "This option was deprecated in 0.6.0. Use router-level middlewares instead."
            "Scheduled to remove in 0.7.0",
        ),
    ] = (),
    no_ack: Annotated[
        bool,
        deprecated(
            "This option was deprecated in 0.6.0 to prior to **ack_policy=AckPolicy.MANUAL**. "
            "Scheduled to remove in 0.7.0",
        ),
    ] = EMPTY,
    ack_policy: AckPolicy = EMPTY,
    no_reply: bool = False,
    # AsyncAPI args
    title: str | None = None,
    description: str | None = None,
    include_in_schema: bool = True,
    max_workers: int | None = None,
) -> None:
    """Initialize KafkaRoute.

    Args:
        call:
            Message handler function
            to wrap the same with `@broker.subscriber(...)` way.
        *topics: "Kafka topics to consume messages from.
        publishers: Kafka publishers to broadcast the handler result.
        batch: Whether to consume messages in batches or not.
        group_id:
            Name of the consumer group to join for dynamic
            partition assignment (if enabled), and to use for fetching and
            committing offsets. If `None`, auto-partition assignment (via
            group coordinator) and offset commits are disabled.
        key_deserializer:
                Any callable that takes a raw message `bytes`
                key and returns a deserialized one.
        value_deserializer:
            Any callable that takes a raw message `bytes`
            value and returns a deserialized value.
        fetch_max_bytes:
            The maximum amount of data the server should
            return for a fetch request. This is not an absolute maximum, if
            the first message in the first non-empty partition of the fetch
            is larger than this value, the message will still be returned
            to ensure that the consumer can make progress. NOTE: consumer
            performs fetches to multiple brokers in parallel so memory
            usage will depend on the number of brokers containing
            partitions for the topic.
        fetch_min_bytes:
            Minimum amount of data the server should
            return for a fetch request, otherwise wait up to
            `fetch_max_wait_ms` for more data to accumulate.
        fetch_max_wait_ms:
            The maximum amount of time in milliseconds
            the server will block before answering the fetch request if
            there isn't sufficient data to immediately satisfy the
            requirement given by `fetch_min_bytes`.
        max_partition_fetch_bytes:
            The maximum amount of data
            per-partition the server will return. The maximum total memory
            used for a request ``= #partitions * max_partition_fetch_bytes``.
            This size must be at least as large as the maximum message size
            the server allows or else it is possible for the producer to
            send messages larger than the consumer can fetch. If that
            happens, the consumer can get stuck trying to fetch a large
            message on a certain partition.
        auto_offset_reset:
            A policy for resetting offsets on `OffsetOutOfRangeError` errors:

            * `earliest` will move to the oldest available message
            * `latest` will move to the most recent
            * `none` will raise an exception so you can handle this case
        auto_commit:
            If `True` the consumer's offset will be
            periodically committed in the background.
        auto_commit_interval_ms:
            Milliseconds between automatic
            offset commits, if `auto_commit` is `True`.
        check_crcs:
            Automatically check the CRC32 of the records
            consumed. This ensures no on-the-wire or on-disk corruption to
            the messages occurred. This check adds some overhead, so it may
            be disabled in cases seeking extreme performance.
        partition_assignment_strategy:
            List of objects to use to
            distribute partition ownership amongst consumer instances when
            group management is used. This preference is implicit in the order
            of the strategies in the list. When assignment strategy changes:
            to support a change to the assignment strategy, new versions must
            enable support both for the old assignment strategy and the new
            one. The coordinator will choose the old assignment strategy until
            all members have been updated. Then it will choose the new
            strategy.
        max_poll_interval_ms:
            Maximum allowed time between calls to
            consume messages in batches. If this interval
            is exceeded the consumer is considered failed and the group will
            rebalance in order to reassign the partitions to another consumer
            group member. If API methods block waiting for messages, that time
            does not count against this timeout.
        rebalance_timeout_ms:
            The maximum time server will wait for this
            consumer to rejoin the group in a case of rebalance. In Java client
            this behaviour is bound to `max.poll.interval.ms` configuration,
            but as ``aiokafka`` will rejoin the group in the background, we
            decouple this setting to allow finer tuning by users that use
            `ConsumerRebalanceListener` to delay rebalacing. Defaults
            to ``session_timeout_ms``
        session_timeout_ms:
            Client group session and failure detection
            timeout. The consumer sends periodic heartbeats
            (`heartbeat.interval.ms`) to indicate its liveness to the broker.
            If no hearts are received by the broker for a group member within
            the session timeout, the broker will remove the consumer from the
            group and trigger a rebalance. The allowed range is configured with
            the **broker** configuration properties
            `group.min.session.timeout.ms` and `group.max.session.timeout.ms`.
        heartbeat_interval_ms:
            The expected time in milliseconds
            between heartbeats to the consumer coordinator when using
            Kafka's group management feature. Heartbeats are used to ensure
            that the consumer's session stays active and to facilitate
            rebalancing when new consumers join or leave the group. The
            value must be set lower than `session_timeout_ms`, but typically
            should be set no higher than 1/3 of that value. It can be
            adjusted even lower to control the expected time for normal
            rebalances.
        consumer_timeout_ms:
            Maximum wait timeout for background fetching
            routine. Mostly defines how fast the system will see rebalance and
            request new data for new partitions.
        max_poll_records:
            The maximum number of records returned in a
            single call by batch consumer. Has no limit by default.
        exclude_internal_topics:
            Whether records from internal topics
            (such as offsets) should be exposed to the consumer. If set to True
            the only way to receive records from an internal topic is
            subscribing to it.
        isolation_level:
            Controls how to read messages written
            transactionally.

            * `read_committed`, batch consumer will only return
            transactional messages which have been committed.

            * `read_uncommitted` (the default), batch consumer will
            return all messages, even transactional messages which have been
            aborted.

            Non-transactional messages will be returned unconditionally in
            either mode.

            Messages will always be returned in offset order. Hence, in
            `read_committed` mode, batch consumer will only return
            messages up to the last stable offset (ALSO), which is the one less
            than the offset of the first open transaction. In particular any
            messages appearing after messages belonging to ongoing transactions
            will be withheld until the relevant transaction has been completed.
            As a result, `read_committed` consumers will not be able to read up
            to the high watermark when there are in flight transactions.
            Further, when in `read_committed` the seek_to_end method will
            return the ALSO. See method docs below.
        batch_timeout_ms:
            Milliseconds spent waiting if
            data is not available in the buffer. If 0, returns immediately
            with any records that are available currently in the buffer,
            else returns empty.
        max_records: Number of messages to consume as one batch.
        listener:
            Optionally include listener
            callback, which will be called before and after each rebalance
            operation.
            As part of group management, the consumer will keep track of
            the list of consumers that belong to a particular group and
            will trigger a rebalance operation if one of the following
            events trigger:

            * Number of partitions change for any of the subscribed topics
            * Topic is created or deleted
            * An existing member of the consumer group dies
            * A new member is added to the consumer group

            When any of these events are triggered, the provided listener
            will be invoked first to indicate that the consumer's
            assignment has been revoked, and then again when the new
            assignment has been received. Note that this listener will
            immediately override any listener set in a previous call
            to subscribe. It is guaranteed, however, that the partitions
            revoked/assigned
            through this interface are from topics subscribed in this call.
        pattern: Pattern to match available topics. You must provide either topics or pattern, but not both.
        partitions: A topic and partition tuple. You can't use 'topics' and 'partitions' in the same time.
        dependencies: Dependencies list (`[Dependant(),]`) to apply to the subscriber.
        parser: Parser to map original **ConsumerRecord** object to FastStream one.
        decoder: Function to decode FastStream msg bytes body to python objects.
        middlewares: Subscriber middlewares to wrap incoming message processing.
        no_ack: Whether to disable **FastStream** auto acknowledgement logic or not.
        ack_policy: AckPolicy = EMPTY,
        no_reply: Whether to disable **FastStream** RPC and Reply To auto responses or not.
        title: AsyncAPI subscriber object title.
        description:
            AsyncAPI subscriber object description.
            Uses decorated docstring as default.
        include_in_schema: Whetever to include operation in AsyncAPI schema or not.
        max_workers: Number of workers to process messages concurrently.
    """
    super().__init__(
        call,
        *topics,
        publishers=publishers,
        max_workers=max_workers,
        group_id=group_id,
        key_deserializer=key_deserializer,
        value_deserializer=value_deserializer,
        fetch_max_wait_ms=fetch_max_wait_ms,
        fetch_max_bytes=fetch_max_bytes,
        fetch_min_bytes=fetch_min_bytes,
        max_partition_fetch_bytes=max_partition_fetch_bytes,
        auto_offset_reset=auto_offset_reset,
        auto_commit=auto_commit,
        auto_commit_interval_ms=auto_commit_interval_ms,
        check_crcs=check_crcs,
        partition_assignment_strategy=partition_assignment_strategy,
        max_poll_interval_ms=max_poll_interval_ms,
        rebalance_timeout_ms=rebalance_timeout_ms,
        session_timeout_ms=session_timeout_ms,
        heartbeat_interval_ms=heartbeat_interval_ms,
        consumer_timeout_ms=consumer_timeout_ms,
        max_poll_records=max_poll_records,
        exclude_internal_topics=exclude_internal_topics,
        isolation_level=isolation_level,
        max_records=max_records,
        batch_timeout_ms=batch_timeout_ms,
        batch=batch,
        listener=listener,
        pattern=pattern,
        partitions=partitions,
        # basic args
        dependencies=dependencies,
        parser=parser,
        decoder=decoder,
        middlewares=middlewares,
        no_reply=no_reply,
        ack_policy=ack_policy,
        no_ack=no_ack,
        # AsyncAPI args
        title=title,
        description=description,
        include_in_schema=include_in_schema,
    )

args instance-attribute

args = args

kwargs instance-attribute

kwargs = kwargs

call instance-attribute

call = call

publishers instance-attribute

publishers = publishers