+public class ShardManager extends AbstractUntypedPersistentActorWithMetering {
+
+ protected final LoggingAdapter LOG =
+ Logging.getLogger(getContext().system(), this);
+
+ // Stores a mapping between a member name and the address of the member
+ // Member names look like "member-1", "member-2" etc and are as specified
+ // in configuration
+ private final Map<String, Address> memberNameToAddress = new HashMap<>();
+
+ // Stores a mapping between a shard name and it's corresponding information
+ // Shard names look like inventory, topology etc and are as specified in
+ // configuration
+ private final Map<String, ShardInformation> localShards = new HashMap<>();
+
+ // The type of a ShardManager reflects the type of the datastore itself
+ // A data store could be of type config/operational
+ private final String type;
+
+ private final ClusterWrapper cluster;
+
+ private final Configuration configuration;
+
+ private ShardManagerInfoMBean mBean;
+
+ private final DatastoreContext datastoreContext;
+
+ private final Collection<String> knownModules = new HashSet<>(128);
+
+ /**
+ * @param type defines the kind of data that goes into shards created by this shard manager. Examples of type would be
+ * configuration or operational
+ */
+ protected ShardManager(String type, ClusterWrapper cluster, Configuration configuration,
+ DatastoreContext datastoreContext) {
+
+ this.type = Preconditions.checkNotNull(type, "type should not be null");
+ this.cluster = Preconditions.checkNotNull(cluster, "cluster should not be null");
+ this.configuration = Preconditions.checkNotNull(configuration, "configuration should not be null");
+ this.datastoreContext = datastoreContext;
+
+ // Subscribe this actor to cluster member events
+ cluster.subscribeToMemberEvents(getSelf());
+
+ createLocalShards();
+ }
+
+ public static Props props(final String type,
+ final ClusterWrapper cluster,
+ final Configuration configuration,
+ final DatastoreContext datastoreContext) {
+
+ Preconditions.checkNotNull(type, "type should not be null");
+ Preconditions.checkNotNull(cluster, "cluster should not be null");
+ Preconditions.checkNotNull(configuration, "configuration should not be null");
+
+ return Props.create(new ShardManagerCreator(type, cluster, configuration, datastoreContext));
+ }
+
+ @Override
+ public void handleCommand(Object message) throws Exception {
+ if (message.getClass().equals(FindPrimary.SERIALIZABLE_CLASS)) {
+ findPrimary(FindPrimary.fromSerializable(message));
+ } else if(message instanceof FindLocalShard){
+ findLocalShard((FindLocalShard) message);
+ } else if (message instanceof UpdateSchemaContext) {
+ updateSchemaContext(message);
+ } else if(message instanceof ActorInitialized) {
+ onActorInitialized(message);
+ } else if (message instanceof ClusterEvent.MemberUp){
+ memberUp((ClusterEvent.MemberUp) message);
+ } else if(message instanceof ClusterEvent.MemberRemoved) {
+ memberRemoved((ClusterEvent.MemberRemoved) message);
+ } else if(message instanceof ClusterEvent.UnreachableMember) {
+ ignoreMessage(message);
+ } else{
+ unknownMessage(message);
+ }
+
+ }
+
+ private void onActorInitialized(Object message) {
+ final ActorRef sender = getSender();
+
+ if (sender == null) {
+ return; //why is a non-actor sending this message? Just ignore.
+ }
+
+ String actorName = sender.path().name();
+ //find shard name from actor name; actor name is stringified shardId
+ ShardIdentifier shardId = ShardIdentifier.builder().fromShardIdString(actorName).build();
+
+ if (shardId.getShardName() == null) {
+ return;
+ }
+ markShardAsInitialized(shardId.getShardName());
+ }
+
+ private void markShardAsInitialized(String shardName) {
+ LOG.debug("Initializing shard [{}]", shardName);
+ ShardInformation shardInformation = localShards.get(shardName);
+ if (shardInformation != null) {
+ shardInformation.setShardInitialized(true);
+ }
+ }
+
+ @Override
+ protected void handleRecover(Object message) throws Exception {
+ if(message instanceof SchemaContextModules){
+ SchemaContextModules msg = (SchemaContextModules) message;
+ knownModules.clear();
+ knownModules.addAll(msg.getModules());
+ } else if(message instanceof RecoveryFailure){
+ RecoveryFailure failure = (RecoveryFailure) message;
+ LOG.error(failure.cause(), "Recovery failed");
+ } else if(message instanceof RecoveryCompleted){
+ LOG.info("Recovery complete : {}", persistenceId());
+
+ // Delete all the messages from the akka journal except the last one
+ deleteMessages(lastSequenceNr() - 1);
+ }
+ }
+
+ private void findLocalShard(FindLocalShard message) {
+ final ShardInformation shardInformation = localShards.get(message.getShardName());
+
+ if(shardInformation == null){
+ getSender().tell(new LocalShardNotFound(message.getShardName()), getSelf());
+ return;
+ }
+
+ sendResponse(shardInformation, new Supplier<Object>() {
+ @Override
+ public Object get() {
+ return new LocalShardFound(shardInformation.getActor());
+ }
+ });
+ }
+
+ private void sendResponse(ShardInformation shardInformation, Supplier<Object> messageSupplier) {
+ if (shardInformation.getActor() == null || !shardInformation.isShardInitialized()) {
+ getSender().tell(new ActorNotInitialized(), getSelf());
+ return;
+ }
+
+ getSender().tell(messageSupplier.get(), getSelf());
+ }
+
+ private void memberRemoved(ClusterEvent.MemberRemoved message) {
+ memberNameToAddress.remove(message.member().roles().head());
+ }
+
+ private void memberUp(ClusterEvent.MemberUp message) {
+ String memberName = message.member().roles().head();
+
+ memberNameToAddress.put(memberName, message.member().address());
+
+ for(ShardInformation info : localShards.values()){
+ String shardName = info.getShardName();
+ info.updatePeerAddress(getShardIdentifier(memberName, shardName),
+ getShardActorPath(shardName, memberName));
+ }
+ }
+
+ /**
+ * Notifies all the local shards of a change in the schema context
+ *
+ * @param message
+ */
+ private void updateSchemaContext(final Object message) {
+ final SchemaContext schemaContext = ((UpdateSchemaContext) message).getSchemaContext();
+
+ Set<ModuleIdentifier> allModuleIdentifiers = schemaContext.getAllModuleIdentifiers();
+ Set<String> newModules = new HashSet<>(128);
+
+ for(ModuleIdentifier moduleIdentifier : allModuleIdentifiers){
+ String s = moduleIdentifier.getNamespace().toString();
+ newModules.add(s);
+ }
+
+ if(newModules.containsAll(knownModules)) {
+
+ LOG.info("New SchemaContext has a super set of current knownModules - persisting info");
+
+ knownModules.clear();
+ knownModules.addAll(newModules);
+
+ persist(new SchemaContextModules(newModules), new Procedure<SchemaContextModules>() {
+
+ @Override
+ public void apply(SchemaContextModules param) throws Exception {
+ LOG.info("Sending new SchemaContext to Shards");
+ for (ShardInformation info : localShards.values()) {
+ if(info.getActor() == null) {
+ info.setActor(getContext().actorOf(Shard.props(info.getShardId(),
+ info.getPeerAddresses(), datastoreContext, schemaContext),
+ info.getShardId().toString()));
+ } else {
+ info.getActor().tell(message, getSelf());
+ }
+ }
+ }
+
+ });
+ } else {
+ LOG.info("Rejecting schema context update because it is not a super set of previously known modules");
+ }
+
+ }
+
+ private void findPrimary(FindPrimary message) {
+ String shardName = message.getShardName();
+
+ // First see if the there is a local replica for the shard
+ final ShardInformation info = localShards.get(shardName);
+ if (info != null) {
+ sendResponse(info, new Supplier<Object>() {
+ @Override
+ public Object get() {
+ return new PrimaryFound(info.getActorPath().toString()).toSerializable();
+ }
+ });
+
+ return;
+ }
+
+ List<String> members = configuration.getMembersFromShardName(shardName);
+
+ if(cluster.getCurrentMemberName() != null) {
+ members.remove(cluster.getCurrentMemberName());
+ }
+
+ /**
+ * FIXME: Instead of sending remote shard actor path back to sender,
+ * forward FindPrimary message to remote shard manager
+ */
+ // There is no way for us to figure out the primary (for now) so assume
+ // that one of the remote nodes is a primary
+ for(String memberName : members) {
+ Address address = memberNameToAddress.get(memberName);
+ if(address != null){
+ String path =
+ getShardActorPath(shardName, memberName);
+ getSender().tell(new PrimaryFound(path).toSerializable(), getSelf());
+ return;
+ }
+ }
+ getSender().tell(new PrimaryNotFound(shardName).toSerializable(), getSelf());
+ }
+
+ private String getShardActorPath(String shardName, String memberName) {
+ Address address = memberNameToAddress.get(memberName);
+ if(address != null) {
+ StringBuilder builder = new StringBuilder();
+ builder.append(address.toString())
+ .append("/user/")
+ .append(ShardManagerIdentifier.builder().type(type).build().toString())
+ .append("/")
+ .append(getShardIdentifier(memberName, shardName));
+ return builder.toString();
+ }
+ return null;
+ }
+
+ /**
+ * Construct the name of the shard actor given the name of the member on
+ * which the shard resides and the name of the shard
+ *
+ * @param memberName
+ * @param shardName
+ * @return
+ */
+ private ShardIdentifier getShardIdentifier(String memberName, String shardName){
+ return ShardIdentifier.builder().memberName(memberName).shardName(shardName).type(type).build();
+ }
+
+ /**
+ * Create shards that are local to the member on which the ShardManager
+ * runs
+ *
+ */
+ private void createLocalShards() {
+ String memberName = this.cluster.getCurrentMemberName();
+ List<String> memberShardNames =
+ this.configuration.getMemberShardNames(memberName);
+
+ List<String> localShardActorNames = new ArrayList<>();
+ for(String shardName : memberShardNames){
+ ShardIdentifier shardId = getShardIdentifier(memberName, shardName);
+ Map<ShardIdentifier, String> peerAddresses = getPeerAddresses(shardName);
+ localShardActorNames.add(shardId.toString());
+ localShards.put(shardName, new ShardInformation(shardName, shardId, peerAddresses));
+ }