hop.io¶

class hop.io.Consumer(group_id, broker_addresses, topics, ignoretest=True, fetch_external: bool = True, **kwargs)[source]¶

An event stream opened for reading one or more topics. Instances of this class should be obtained from Stream.open().

static is_test(message)[source]¶

True if message is a test message (contains ‘_test’ as a header key).

mark_done(metadata, asynchronous: bool = True)[source]¶

Mark a message as fully-processed.

Parameters:

metadata – A Metadata instance containing broker-specific metadata.
asynchronous – Whether to allow the commit to happen asynchronously in the background.

read(metadata=False, autocommit=True, **kwargs)[source]¶

Read messages from a stream.

Parameters:

metadata – Whether to receive message metadata alongside messages.
autocommit – Whether messages are automatically marked as handled via mark_done when the next message is yielded. Defaults to True.
batch_size – The number of messages to request from Kafka at a time. Lower numbers can give lower latency, while higher numbers will be more efficient, but may add latency.
batch_timeout – The period of time to wait to get a full batch of messages from Kafka. Similar to batch_size, lower numbers can reduce latency while higher numbers can be more efficient at the cost of greater latency. If specified, this argument should be a datetime.timedelta object.

read_raw(metadata=False, autocommit=True, **kwargs)[source]¶

Read messages from a stream without applying any deserialization.

This is an advanced interface; for most purposes it is preferable to use Consumer.read instead.

Parameters:

metadata – Whether to receive message metadata alongside messages.
autocommit – Whether messages are automatically marked as handled via mark_done when the next message is yielded. Defaults to True.
batch_size – The number of messages to request from Kafka at a time. Lower numbers can give lower latency, while higher numbers will be more efficient, but may add latency.
batch_timeout – The period of time to wait to get a full batch of messages from Kafka. Similar to batch_size, lower numbers can reduce latency while higher numbers can be more efficient at the cost of greater latency. If specified, this argument should be a datetime.timedelta object.

stop()[source]¶: Stops the runloop of the consumer. Useful when running the consumer in a different thread.

class hop.io.Metadata(topic: str, partition: int, offset: int, timestamp: int, key: str | bytes, headers: List[Tuple[str, bytes]], _raw: Message)[source]¶: Broker-specific metadata that accompanies a consumed message.

class hop.io.Stream(auth=True, start_at=ConsumerDefaultPosition.LATEST, until_eos=False)[source]¶

Defines an event stream.

Sets up defaults used within the client so that when a stream connection is opened, it will use defaults specified here.

Parameters:

auth – A bool or Auth instance. Defaults to loading from auth.load_auth if set to True. To disable authentication, set to False.
start_at – The message offset to start at in read mode. Defaults to LATEST.
until_eos – Whether to listen to new messages forever (False) or stop when EOS is received in read mode (True). Defaults to False.

open(url, mode='r', group_id=None, ignoretest=True, produce_timeout=datetime.timedelta(0), **kwargs)[source]¶

Opens a connection to an event stream.

Parameters:

url – Sets the broker URL to connect to.
mode – Read (‘r’) or write (‘w’) from the stream.
group_id – The consumer group ID from which to read. Generated automatically if not specified.
ignoretest – When True, read mode will silently discard test messages.
produce_timeout – A limit on the time within which each published message must be sent. If zero, no limit is applied, and closing the producer will wait indefinitely for all queued messages to send.

Returns:

An open connection to the client, either a Producer instance in write mode or a Consumer instance in read mode.

Raises:

ValueError – If the mode is not set to read/write, if no topic is specified in read mode, or if more than one broker is specified

hop.io.list_topics(url: str, auth: bool | Auth = True, timeout=-1.0)[source]¶

List the accessible topics on the Kafka broker referred to by url.

Parameters:

url – The Kafka broker URL. Only one broker may be specified. Topics may be specified, in which case only topics in the intersection of the set specified by the URL and actually present on the broker will be returned. If a userinfo component is present in the URL and auth is True, it will be treated as a hint to the automatic auth lookup.
auth – A bool or Auth instance. Defaults to loading from auth.load_auth if set to True. To disable authentication, set to False. If a username is specified as part of url but auth is a Auth instance the url information will be ignored.
timeout – A floating point value, indicating the maximum number of seconds to wait to connect to a broker, or a negative value to indicate no limit.

Returns:

A dictionary mapping topic names to confluent_kafka.admin.TopicMetadata instances.

Raises: