+ private abstract static class LookupTask implements Runnable {
+
+ private final ActorRef replyTo;
+ private int retries = 0;
+
+ private LookupTask(final ActorRef replyTo) {
+ this.replyTo = replyTo;
+ }
+
+ abstract void reschedule(int retries);
+
+ void tryReschedule(@Nullable final Throwable throwable) {
+ if (retries <= LOOKUP_TASK_MAX_RETRIES) {
+ retries++;
+ reschedule(retries);
+ } else {
+ fail(throwable);
+ }
+ }
+
+ void fail(@Nullable final Throwable throwable) {
+ if (throwable == null) {
+ replyTo.tell(new Failure(
+ new DOMDataTreeShardCreationFailedException("Unable to find the backend shard."
+ + "Failing..")), noSender());
+ } else {
+ replyTo.tell(new Failure(
+ new DOMDataTreeShardCreationFailedException("Unable to find the backend shard."
+ + "Failing..", throwable)), noSender());
+ }
+ }
+ }
+
+ /**
+ * Handles the lookup step of cds shard creation once the configuration is updated.
+ */
+ private static class ShardCreationLookupTask extends LookupTask {
+
+ private final ActorSystem system;
+ private final ActorRef replyTo;
+ private final ClusterWrapper clusterWrapper;
+ private final ActorContext context;
+ private final DistributedShardedDOMDataTree shardingService;
+ private final DOMDataTreeIdentifier toLookup;
+
+ ShardCreationLookupTask(final ActorSystem system,
+ final ActorRef replyTo,
+ final ClusterWrapper clusterWrapper,
+ final ActorContext context,
+ final DistributedShardedDOMDataTree shardingService,
+ final DOMDataTreeIdentifier toLookup) {
+ super(replyTo);
+ this.system = system;
+ this.replyTo = replyTo;
+ this.clusterWrapper = clusterWrapper;
+ this.context = context;
+ this.shardingService = shardingService;
+ this.toLookup = toLookup;
+ }
+
+ @Override
+ public void run() {
+ final Future<ActorRef> localShardFuture =
+ context.findLocalShardAsync(ClusterUtils.getCleanShardName(toLookup.getRootIdentifier()));
+
+ localShardFuture.onComplete(new OnComplete<ActorRef>() {
+ @Override
+ public void onComplete(Throwable throwable, ActorRef actorRef) throws Throwable {
+ if (throwable != null) {
+ tryReschedule(throwable);
+ } else {
+ LOG.debug("Local backend for shard[{}] lookup successful, starting leader lookup..", toLookup);
+
+ system.scheduler().scheduleOnce(
+ SHARD_LOOKUP_TASK_INTERVAL,
+ new ShardLeaderLookupTask(system, replyTo, context, clusterWrapper, actorRef,
+ shardingService, toLookup),
+ system.dispatcher());
+ }
+ }
+ }, system.dispatcher());
+ }
+
+ @Override
+ void reschedule(int retries) {
+ LOG.debug("Local backend for shard[{}] not found, try: {}, rescheduling..", toLookup, retries);
+ system.scheduler().scheduleOnce(
+ SHARD_LOOKUP_TASK_INTERVAL, ShardCreationLookupTask.this, system.dispatcher());
+ }
+ }
+
+ /**
+ * Handles the readiness step by waiting for a leader of the created shard.
+ */
+ private static class ShardLeaderLookupTask extends LookupTask {
+
+ private final ActorSystem system;
+ private final ActorRef replyTo;
+ private final ActorContext context;
+ private final ClusterWrapper clusterWrapper;
+ private final ActorRef shard;
+ private final DistributedShardedDOMDataTree shardingService;
+ private final DOMDataTreeIdentifier toLookup;
+
+ ShardLeaderLookupTask(final ActorSystem system,
+ final ActorRef replyTo,
+ final ActorContext context,
+ final ClusterWrapper clusterWrapper,
+ final ActorRef shard,
+ final DistributedShardedDOMDataTree shardingService,
+ final DOMDataTreeIdentifier toLookup) {
+ super(replyTo);
+ this.system = system;
+ this.replyTo = replyTo;
+ this.context = context;
+ this.clusterWrapper = clusterWrapper;
+ this.shard = shard;
+ this.shardingService = shardingService;
+ this.toLookup = toLookup;
+ }
+
+ @Override
+ public void run() {
+
+ final Future<Object> ask = Patterns.ask(shard, FindLeader.INSTANCE, context.getOperationTimeout());
+
+ ask.onComplete(new OnComplete<Object>() {
+ @Override
+ public void onComplete(final Throwable throwable, final Object findLeaderReply) throws Throwable {
+ if (throwable != null) {
+ tryReschedule(throwable);
+ } else {
+ final FindLeaderReply findLeader = (FindLeaderReply) findLeaderReply;
+ final java.util.Optional<String> leaderActor = findLeader.getLeaderActor();
+ if (leaderActor.isPresent()) {
+ // leader is found, backend seems ready, check if the frontend is ready
+ LOG.debug("{} - Leader for shard[{}] backend ready, starting frontend lookup..",
+ clusterWrapper.getCurrentMemberName(), toLookup);
+ system.scheduler().scheduleOnce(
+ SHARD_LOOKUP_TASK_INTERVAL,
+ new FrontendLookupTask(system, replyTo, shardingService, toLookup),
+ system.dispatcher());
+ } else {
+ tryReschedule(null);
+ }
+ }
+ }
+ }, system.dispatcher());
+
+ }
+
+ @Override
+ void reschedule(int retries) {
+ LOG.debug("{} - Leader for shard[{}] backend not found on try: {}, retrying..",
+ clusterWrapper.getCurrentMemberName(), toLookup, retries);
+ system.scheduler().scheduleOnce(
+ SHARD_LOOKUP_TASK_INTERVAL, ShardLeaderLookupTask.this, system.dispatcher());
+ }
+ }
+
+ /**
+ * After backend is ready this handles the last step - checking if we have a frontend shard for the backend,
+ * once this completes(which should be ready by the time the backend is created, this is just a sanity check in
+ * case they race), the future for the cds shard creation is completed and the shard is ready for use.
+ */
+ private static final class FrontendLookupTask extends LookupTask {
+
+ private final ActorSystem system;
+ private final ActorRef replyTo;
+ private final DistributedShardedDOMDataTree shardingService;
+ private final DOMDataTreeIdentifier toLookup;
+
+ FrontendLookupTask(final ActorSystem system,
+ final ActorRef replyTo,
+ final DistributedShardedDOMDataTree shardingService,
+ final DOMDataTreeIdentifier toLookup) {
+ super(replyTo);
+ this.system = system;
+ this.replyTo = replyTo;
+ this.shardingService = shardingService;
+ this.toLookup = toLookup;
+ }
+
+ @Override
+ public void run() {
+ final DOMDataTreePrefixTableEntry<DOMDataTreeShardRegistration<DOMDataTreeShard>> entry =
+ shardingService.lookupShardFrontend(toLookup);
+
+ if (entry != null && tableEntryIdCheck(entry, toLookup) && entry.getValue() != null) {
+ replyTo.tell(new Success(null), noSender());
+ } else {
+ tryReschedule(null);
+ }
+ }
+
+ private boolean tableEntryIdCheck(final DOMDataTreePrefixTableEntry<?> entry,
+ final DOMDataTreeIdentifier prefix) {
+ if (entry == null) {
+ return false;
+ }
+
+ if (YangInstanceIdentifier.EMPTY.equals(prefix.getRootIdentifier())) {
+ return true;
+ }
+
+ if (entry.getIdentifier().equals(toLookup.getRootIdentifier().getLastPathArgument())) {
+ return true;
+ }
+
+ return false;
+ }
+
+ @Override
+ void reschedule(int retries) {
+ LOG.debug("Frontend for shard[{}] not found on try: {}, retrying..", toLookup, retries);
+ system.scheduler().scheduleOnce(
+ SHARD_LOOKUP_TASK_INTERVAL, FrontendLookupTask.this, system.dispatcher());
+ }
+ }
+
+ /**
+ * Task that is run once a cds shard registration is closed and completes once the backend shard is removed from the
+ * configuration.
+ */
+ private static class ShardRemovalLookupTask extends LookupTask {
+
+ private final ActorSystem system;
+ private final ActorRef replyTo;
+ private final ActorContext context;
+ private final DOMDataTreeIdentifier toLookup;
+
+ ShardRemovalLookupTask(final ActorSystem system,
+ final ActorRef replyTo,
+ final ActorContext context,
+ final DOMDataTreeIdentifier toLookup) {
+ super(replyTo);
+ this.system = system;
+ this.replyTo = replyTo;
+ this.context = context;
+ this.toLookup = toLookup;
+ }
+
+ @Override
+ public void run() {
+ final Future<ActorRef> localShardFuture =
+ context.findLocalShardAsync(ClusterUtils.getCleanShardName(toLookup.getRootIdentifier()));
+
+ localShardFuture.onComplete(new OnComplete<ActorRef>() {
+ @Override
+ public void onComplete(Throwable throwable, ActorRef actorRef) throws Throwable {
+ if (throwable != null) {
+ //TODO Shouldn't we check why findLocalShard failed?
+ LOG.debug("Backend shard[{}] removal lookup successful notifying the registration future",
+ toLookup);
+ replyTo.tell(new Success(null), noSender());
+ } else {
+ tryReschedule(null);
+ }
+ }
+ }, system.dispatcher());
+ }
+
+ @Override
+ void reschedule(int retries) {
+ LOG.debug("Backend shard[{}] removal lookup failed, shard is still present, try: {}, rescheduling..",
+ toLookup, retries);
+ system.scheduler().scheduleOnce(
+ SHARD_LOOKUP_TASK_INTERVAL, ShardRemovalLookupTask.this, system.dispatcher());
+ }
+ }
+