Reusable cluster member group¶

Typically on a big project it is useful to start a cluster and then reuse it across the various test classes or suites, littlegrid 2.15 introduced a ‘productised’ feature to easily keep an established cluster up and running across test classes (previously there were some workarounds).

SimpleKeepAliveClusterMemberGroup¶

The simple keep-alive cluster member group enables the cluster member group (essentially members within a cluster) to be reused across test classes. Once created and started, any requests for the same member group return the original instance and when it is requested to be shutdown, it simply ignores the request.

The simple keep-alive cluster member group is ideal for a testing classes within a module that all require the same type of cluster across all the tests. The member group is effectively cleared up when the test process ends.

memberGroup = ClusterMemberGroupUtils.newBuilder()
    .setClusterMemberGroupInstanceClassName(SimpleKeepAliveClusterMemberGroup.class.getName())
    .setStorageEnabledCount(2)
    .buildAndConfigureForStorageDisabledClient();

NamedCache cache = CacheFactory.getCache("test");

That’s it, simple Controlling and configuring littlegrid configure the littlegrid builder ClusterMemberGroupInstanceClassName with the name of the SimpleKeepAliveClusterMemberGroup.

UsageCountingClusterMemberGroup¶

The usage counting cluster member group is typically useful when test classes have been gathered up into test suites, this technique is typically used on modules where different types of cluster are required across different test classes within the module. Many projects won’t need the usage counting member group and the simple keep-alive member group should be the starting point.