Create a sink that acknowledges messages and records processing latencies in the AckDeadlineDistribution for adaptive deadline computation.

Create a sink that acknowledges messages and releases FlowControl permits.

Create a sink that accepts consumed message acknowledgements.

The materialized value completes on stream completion.

Create a flow that acknowledges messages and records processing latencies in the AckDeadlineDistribution for adaptive deadline computation.

Create a flow that acknowledges messages and releases FlowControl permits.

Create a flow that automatically extends ack deadlines using an adaptive deadline based on observed processing times, matching Google's official client library behavior.

Instead of a fixed deadline, the extension deadline is computed from the 99th percentile (configurable) of actual ack latencies. This means:

• If messages typically process in 2s, deadlines stay short (~10s) for fast redelivery on failure
• If messages take 45s, deadlines adapt upward to avoid unnecessary redelivery

The same AckDeadlineDistribution must be passed to the acknowledge/nack operators so that processing latencies are recorded.

Usage:

val dist = AckDeadlineDistribution(initialDeadlineSeconds = 10)

GooglePubSub.subscribe(request, 1.second, restartSettings)
  .via(GooglePubSub.autoExtendAckDeadlines(subscriptionFqrs, 3.seconds, dist))
  .mapAsync(4)(processMessage)
  .map(msg => AcknowledgeRequest(subscriptionFqrs, Seq(msg.ackId)))
  .to(GooglePubSub.acknowledge(parallelism = 1, dist))

Create a flow that automatically extends ack deadlines for messages passing through it.

A background timer periodically sends ModifyAckDeadline RPCs for all tracked messages, preventing Pub/Sub from redelivering them while they are being processed downstream. Messages are tracked from the moment they enter the flow until the stream completes, fails, or maxAckExtensionPeriod elapses. Messages are NOT removed from tracking upon acknowledgment; extending the deadline of an already-acknowledged message is a safe server-side no-op. For tracking that stops on acknowledgment, use the adaptive variant with AckDeadlineDistribution.

If the background lease-extension ticker fails (e.g. due to a network error in the ModifyAckDeadline RPC), the main stream will be aborted immediately with an org.apache.pekko.stream.connectors.googlecloud.pubsub.grpc.AckDeadlineExtensionException, even if the stream is idle.

Create a flow that automatically extends ack deadlines for messages passing through it.

A background timer periodically sends ModifyAckDeadline RPCs for all tracked messages, preventing Pub/Sub from redelivering them while they are being processed downstream. Messages are tracked from the moment they enter the flow until the stream completes, fails, or maxAckExtensionPeriod elapses (default 60 minutes, matching Google's client library). Messages are NOT removed from tracking upon acknowledgment; extending the deadline of an already-acknowledged message is a safe server-side no-op. For tracking that stops on acknowledgment, use the adaptive variant with AckDeadlineDistribution.

If the background lease-extension ticker fails (e.g. due to a network error in the ModifyAckDeadline RPC), the main stream will be aborted immediately with an org.apache.pekko.stream.connectors.googlecloud.pubsub.grpc.AckDeadlineExtensionException, even if the stream is idle.

Usage:

GooglePubSub.subscribe(request, 1.second)
  .via(GooglePubSub.autoExtendAckDeadlines(subscriptionFqrs, 8.seconds, 30))
  .mapAsync(4)(processMessage)
  .map(msg => AcknowledgeRequest(subscriptionFqrs, Seq(msg.ackId)))
  .to(GooglePubSub.acknowledge(parallelism = 1))

Create a flow that gates messages based on FlowControl, applying backpressure when the number of outstanding (unacknowledged) messages reaches the limit.

Pair with a FlowControl-aware acknowledge or nack operator to release permits.

Create a sink that accepts ack deadline modifications.

This can be used to extend the acknowledgement deadline for messages that require longer processing times, preventing Pub/Sub from redelivering them.

The materialized value completes on stream completion.

Create a flow that modifies the ack deadline for each message using a dynamic function.

This allows per-message deadline control — for example, setting longer deadlines for messages that are expected to take longer to process.

Returning 0 from the function is equivalent to a nack (immediate redelivery).

Create a flow that accepts ack deadline modifications.

This can be used to extend the acknowledgement deadline for messages that require longer processing times, preventing Pub/Sub from redelivering them.

Create a sink that nacks messages and records processing latencies in the AckDeadlineDistribution for adaptive deadline computation.

Create a sink that nacks messages and releases FlowControl permits.

Create a sink that nacks messages by setting the ack deadline to 0, causing Pub/Sub to immediately redeliver them.

The materialized value completes on stream completion.

Create a flow that nacks messages and records processing latencies in the AckDeadlineDistribution for adaptive deadline computation.

Create a flow that nacks messages and releases FlowControl permits.

Create a flow that nacks messages by setting the ack deadline to 0, causing Pub/Sub to immediately redeliver them.

Accepts AcknowledgeRequest for consistency with the acknowledge API — the subscription and ack IDs are reused to build the underlying ModifyAckDeadlineRequest with ackDeadlineSeconds = 0.

Create a flow to publish messages to Google Cloud Pub/Sub. The flow emits responses that contain published message ids.

Create a source that emits messages for a given subscription using a StreamingPullRequest.

Automatically reconnects when the server closes the StreamingPull connection (due to idle timeout, rebalancing, etc.), matching the behavior of Google's official client library. All errors trigger reconnection with exponential backoff, including non-retryable errors such as PERMISSION_DENIED or NOT_FOUND. Use RestartSettings.withMaxRestarts to bound the total number of restart attempts; when exhausted the stream fails with the last error.

Create a source that emits messages for a given subscription using a StreamingPullRequest.

The materialized value can be used to cancel the source.

Create a source that emits messages for a given subscription using a synchronous PullRequest.

The materialized value can be used to cancel the source.