As of January 1, 2020 this library no longer supports Python 2 on the latest released version. Library versions released prior to that date will continue to be available. For more information please visit Python 2 support on Google Cloud.

Subscriber Client API

class google.cloud.pubsublite.cloudpubsub.subscriber_client.AsyncSubscriberClient(*, nack_handler: Optional[google.cloud.pubsublite.cloudpubsub.nack_handler.NackHandler] = None, reassignment_handler: Optional[google.cloud.pubsublite.cloudpubsub.reassignment_handler.ReassignmentHandler] = None, message_transformer: Optional[google.cloud.pubsublite.cloudpubsub.message_transformer.MessageTransformer] = None, credentials: Optional[google.auth.credentials.Credentials] = None, transport: str = 'grpc_asyncio', client_options: Optional[google.api_core.client_options.ClientOptions] = None)

An AsyncSubscriberClient reads messages similar to Google Pub/Sub, but must be used in an async context. Any subscribe failures are unlikely to succeed if retried.

Must be used in an async with block or have __aenter__() awaited before use.

Create a new AsyncSubscriberClient.

Parameters

• nack_handler – A handler for when nack() is called. The default NackHandler raises an exception and fails the subscribe stream.

• message_transformer – A transformer from Pub/Sub Lite messages to Cloud Pub/Sub messages. This may not return a message with “message_id” set.

• credentials – If provided, the credentials to use when connecting.

• transport – The transport to use. Must correspond to an asyncio transport.

• client_options – The client options to use when connecting. If used, must explicitly set api_endpoint.

async __aenter__()

Return self upon entering the runtime context.

async __aexit__(exc_type, exc_value, traceback)

Raise any exception triggered within the runtime context.

async subscribe(subscription: Union[google.cloud.pubsublite.types.paths.SubscriptionPath, str], per_partition_flow_control_settings: google.cloud.pubsublite.types.flow_control_settings.FlowControlSettings, fixed_partitions: Optional[Set[google.cloud.pubsublite.types.partition.Partition]] = None) → AsyncIterator[google.cloud.pubsub_v1.subscriber.message.Message]

Read messages from a subscription.

Parameters

• subscription – The subscription to subscribe to.

• per_partition_flow_control_settings – The flow control settings for each partition subscribed to. Note that these settings apply to each partition individually, not in aggregate.

• fixed_partitions – A fixed set of partitions to subscribe to. If not present, will instead use auto-assignment.

Returns

An AsyncIterator with Messages that must have ack() called on each exactly once.

Raises

GoogleApiCallError – On a permanent failure.

class google.cloud.pubsublite.cloudpubsub.subscriber_client.SubscriberClient(*, executor: Optional[concurrent.futures.thread.ThreadPoolExecutor] = None, nack_handler: Optional[google.cloud.pubsublite.cloudpubsub.nack_handler.NackHandler] = None, reassignment_handler: Optional[google.cloud.pubsublite.cloudpubsub.reassignment_handler.ReassignmentHandler] = None, message_transformer: Optional[google.cloud.pubsublite.cloudpubsub.message_transformer.MessageTransformer] = None, credentials: Optional[google.auth.credentials.Credentials] = None, transport: str = 'grpc_asyncio', client_options: Optional[google.api_core.client_options.ClientOptions] = None)

A SubscriberClient reads messages similar to Google Pub/Sub. Any subscribe failures are unlikely to succeed if retried.

Must be used in a with block or have __enter__() called before use.

Create a new SubscriberClient.

Parameters

• executor – A ThreadPoolExecutor to use. The client will shut it down on __exit__. If provided a single threaded executor, messages will be ordered per-partition, but take care that the callback does not block for too long as it will impede forward progress on all subscriptions.

• nack_handler – A handler for when nack() is called. The default NackHandler raises an exception and fails the subscribe stream.

• message_transformer – A transformer from Pub/Sub Lite messages to Cloud Pub/Sub messages. This may not return a message with “message_id” set.

• credentials – If provided, the credentials to use when connecting.

• transport – The transport to use. Must correspond to an asyncio transport.

• client_options – The client options to use when connecting. If used, must explicitly set api_endpoint.

__enter__()

Return self upon entering the runtime context.

__exit__(exc_type, exc_value, traceback)

Raise any exception triggered within the runtime context.

subscribe(subscription: Union[google.cloud.pubsublite.types.paths.SubscriptionPath, str], callback: Callable[[google.cloud.pubsub_v1.subscriber.message.Message], None], per_partition_flow_control_settings: google.cloud.pubsublite.types.flow_control_settings.FlowControlSettings, fixed_partitions: Optional[Set[google.cloud.pubsublite.types.partition.Partition]] = None) → google.cloud.pubsub_v1.subscriber.futures.StreamingPullFuture

This method starts a background thread to begin pulling messages from a Pub/Sub Lite subscription and scheduling them to be processed using the provided callback.

Parameters

• subscription – The subscription to subscribe to.

• callback – The callback function. This function receives the message as its only argument.

• per_partition_flow_control_settings – The flow control settings for each partition subscribed to. Note that these settings apply to each partition individually, not in aggregate.

• fixed_partitions – A fixed set of partitions to subscribe to. If not present, will instead use auto-assignment.

Returns

A StreamingPullFuture instance that can be used to manage the background stream.

Raises

GoogleApiCallError – On a permanent failure.