Alpakka Kafka 1.0-RC1

Released 2018-12-11

First release candidate for Alpakka Kafka 1.0

On this Road to Alpakka 1.0 we may introduce non-compatible API changes. From version 1.0 Alpakka will stay binary-compatible between minor releases.

Having that said, Alpakka Kafka will start to make use of the @ApiMayChange annotation to keep the door open for API changes, so that new feature API can evolve more rapidly than other parts of Alpakka Kafka.

Highlights in this release

Use Kafka client 2.x poll API #614, investigated by @zaharidichev
No more WakeupException! The Kafka client API 2.x allows for specifying a timeout when polling the Kafka broker, thus we do not need to use the cranky tool of Kafka’s WakeupExceptions to be sure not to block a precious thread. The settings to configure wake-ups are not used anymore.
Upgrade to Kafka client 2.1.0 #660. This upgrade makes it possible to use of the zstandard compression (with Kafka 2.1 brokers).
Consumer shutdown is now delayed by stop-timeout (default 30 s) #673. This is especially relevant for committable partitioned sources as the stage needs to stay alive until committing has finished (reported in #672).
API Change: Alpakka Kafka consumers don’t fail for non-responding Kafka brokers anymore (as they used to to after a number of WakeupExceptions). To get the connectivity check back #674 suggests a possible way forward.
API Change: Standardised on spelling of committable in Producer.committableSink (Producer.commitableSink will be kept around throughout 1.0.x, but those methods are deprecated now) #645
New Committer.flow for standardised committing within a continuing flow #644
API Change: The response to the metadata request GetCommittedOffset now contains the TopicPartition #626 by @giftig.
API Change: Manual subscriptions (Subscriptions.assignment, assignmentWithOffset, assignmentOffsetsForTimes) do not allow setting a rebalance listener anymore (methods deprecated). Rebalancing does not occur for those #639.
Improvements to the new testkit #656, initiated by @johnclara’s work with the admin clients.
Continuous integration builds are now run against Adopt OpenJDK 8 and 11 #641.

Improved documentation

All examples now use the Committer instead of commitJavadsl/commitScaladsl.
Most examples now show the use of DrainingControl.
The Java examples shown in the documentation are now run in the tests #665.
Show transitive dependencies in the documentation #657

Everything done in this release is in the 1.0-RC1 milestone.

Other Highlights already in M1

New Committer.sink for standardised committing #622 by @rtimush
Commit with metadata #563 and #579 by @johnclara
Factored out akka.kafka.testkit for internal and external use: see Testing
Support for merging commit batches #584 by @rtimush
Reduced risk of message loss for partitioned sources #589
Expose Kafka errors to stream #617
Java APIs for all settings classes #616
Much more comprehensive tests

General information

This release is compiled and tested against Akka 2.5 and Scala 2.11 and 2.12.

This release was made possible by new and earlier contributors:

Author	Commits	Lines added	Lines removed
ennru	40	2630	1979
2m	17	326	282
muditsin	2	14	10
zaharidichev	1	21	241
John Clara	1	20	6
giftig	1	6	5
fancywriter	1	1	1