pekko/akka-contrib
Patrik Nordwall d98a7ef1e8 Cluster singleton failure due to down-removed, see #3130
* The scenario was that previous leader left.
* The problem was that the new leader got MemberRemoved
  before it got the HandOverDone and therefore missed the
  hand over data.
* Solved by not changing the singleton to leader when receiving
  MemberRemoved and instead do that on normal HandOverDone or
  in failure cases after retry timeout.
* The reason for this bug was the new transition from Down to
  Removed and that there is now no MemberDowned event. Previously
  this was only triggered by MemberDowned (not MemberRemoved) and
  that was safe because that was "always" preceeded by unreachable.
* The new solution means that it will take longer for new singleton
  to startup in case of unreachable previous leader, but I don't
  want to trigger it on MemberUnreachable because it might in the
  future be possible to switch it back to reachable.
2013-03-11 12:37:35 +01:00
..
docs move multi-node-testkit into its own module, see #2981 2013-02-11 14:37:37 +01:00
src Cluster singleton failure due to down-removed, see #3130 2013-03-11 12:37:35 +01:00
README.md fixes based on review comments 2012-10-02 11:37:31 +02:00

External Contributions

This subproject provides a home to modules contributed by external developers which may or may not move into the officially supported code base over time. The conditions under which this transition can occur include:

  • there must be enough interest in the module to warrant inclusion in the standard distribution,
  • the module must be actively maintained and
  • code quality must be good enough to allow efficient maintenance by the Akka core development team

If a contributions turns out to not “take off” it may be removed again at a later time.

Caveat Emptor

A module in this subproject doesn't have to obey the rule of staying binary compatible between micro releases. Breaking API changes may be introduced in minor releases without notice as we refine and simplify based on your feedback. A module may be dropped in any release without prior deprecation. The Typesafe subscription does not cover support for these modules.

Suggested Format of Contributions

Each contribution should be a self-contained unit, consisting of one source file or one exclusively used package, without dependencies to other modules in this subproject; it may depend on everything else in the Akka distribution, though. This ensures that contributions may be moved into the standard distribution individually. The module shall be within a subpackage of akka.contrib.

Each module must be accompanied by a test suite which verifies that the provided features work, possibly complemented by integration and unit tests. The tests should follow the Developer Guidelines and go into the src/test/scala or src/test/java directories (with package name matching the module which is being tested). As an example, if the module were called akka.contrib.pattern.ReliableProxy, then the test suite should be called akka.contrib.pattern.ReliableProxySpec.

Each module must also have proper documentation in reStructured Text format. The documentation should be a single <module>.rst file in the akka-contrib/docs directory, including a link from index.rst.

Suggested Way of Using these Contributions

Since the Akka team does not restrict updates to this subproject even during otherwise binary compatible releases, and modules may be removed without deprecation, it is suggested to copy the source files into your own code base, changing the package name. This way you can choose when to update or which fixes to include (to keep binary compatibility if needed) and later releases of Akka do not potentially break your application.