use of akka.stream.KillSwitch in project torodb by torodb.
the class DefaultOplogApplier method apply.
@Override
public ApplyingJob apply(OplogFetcher fetcher, ApplierContext applierContext) {
Materializer materializer = ActorMaterializer.create(actorSystem);
RunnableGraph<Pair<UniqueKillSwitch, CompletionStage<Done>>> graph = createOplogSource(fetcher).async().via(createBatcherFlow(applierContext)).viaMat(KillSwitches.single(), Keep.right()).async().map(analyzedElem -> {
for (AnalyzedOplogBatch analyzedOplogBatch : analyzedElem.analyzedBatch) {
batchExecutor.apply(analyzedOplogBatch, applierContext);
}
return analyzedElem;
}).map(this::metricExecution).toMat(Sink.foreach(this::storeLastAppliedOp), (killSwitch, completionStage) -> new Pair<>(killSwitch, completionStage));
Pair<UniqueKillSwitch, CompletionStage<Done>> pair = graph.run(materializer);
UniqueKillSwitch killSwitch = pair.first();
CompletableFuture<Empty> whenComplete = pair.second().toCompletableFuture().thenApply(done -> Empty.getInstance()).whenComplete((done, t) -> {
fetcher.close();
if (done != null) {
LOGGER.trace("Oplog replication stream finished normally");
} else {
Throwable cause;
if (t instanceof CompletionException) {
cause = t.getCause();
} else {
cause = t;
}
//the completable future has been cancelled
if (cause instanceof CancellationException) {
LOGGER.debug("Oplog replication stream has been cancelled");
killSwitch.shutdown();
} else {
//in this case the exception should came from the stream
cause = Throwables.getRootCause(cause);
LOGGER.error("Oplog replication stream finished exceptionally: " + cause.getLocalizedMessage(), cause);
//the stream should be finished exceptionally, but just in case we
//notify the kill switch to stop the stream.
killSwitch.shutdown();
}
}
});
return new DefaultApplyingJob(killSwitch, whenComplete);
}
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