BUG-8639: always invalidate primary info cache
[controller.git] / opendaylight / md-sal / sal-distributed-datastore / src / main / java / org / opendaylight / controller / cluster / databroker / actors / dds / ModuleShardBackendResolver.java
index a1018967e76668b8e1640f86c83d7c2769a5b3d9..ee549d36118e8f026f1ed6e83c80b842fe5bbf50 100644 (file)
@@ -7,35 +7,22 @@
  */
 package org.opendaylight.controller.cluster.databroker.actors.dds;
 
-import akka.actor.ActorRef;
-import akka.util.Timeout;
 import com.google.common.base.Preconditions;
-import com.google.common.base.Throwables;
 import com.google.common.collect.BiMap;
 import com.google.common.collect.ImmutableBiMap;
 import com.google.common.collect.ImmutableBiMap.Builder;
-import com.google.common.primitives.UnsignedLong;
-import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
-import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionStage;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 import javax.annotation.concurrent.GuardedBy;
-import org.opendaylight.controller.cluster.access.ABIVersion;
-import org.opendaylight.controller.cluster.access.client.BackendInfo;
+import javax.annotation.concurrent.ThreadSafe;
 import org.opendaylight.controller.cluster.access.client.BackendInfoResolver;
-import org.opendaylight.controller.cluster.access.commands.ConnectClientRequest;
-import org.opendaylight.controller.cluster.access.commands.ConnectClientSuccess;
 import org.opendaylight.controller.cluster.access.concepts.ClientIdentifier;
-import org.opendaylight.controller.cluster.access.concepts.RequestFailure;
-import org.opendaylight.controller.cluster.common.actor.ExplicitAsk;
 import org.opendaylight.controller.cluster.datastore.shardstrategy.DefaultShardStrategy;
 import org.opendaylight.controller.cluster.datastore.utils.ActorContext;
 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-import scala.Function1;
-import scala.compat.java8.FutureConverters;
 
 /**
  * {@link BackendInfoResolver} implementation for static shard configuration based on ShardManager. Each string-named
@@ -44,24 +31,12 @@ import scala.compat.java8.FutureConverters;
  *
  * @author Robert Varga
  */
-@SuppressFBWarnings(value = "NP_NONNULL_PARAM_VIOLATION",
-                    justification = "Pertains to the NULL_FUTURE field below. Null is allowed and is intended")
-final class ModuleShardBackendResolver extends BackendInfoResolver<ShardBackendInfo> {
-    private static final CompletableFuture<ShardBackendInfo> NULL_FUTURE = CompletableFuture.completedFuture(null);
+@ThreadSafe
+final class ModuleShardBackendResolver extends AbstractShardBackendResolver {
     private static final Logger LOG = LoggerFactory.getLogger(ModuleShardBackendResolver.class);
 
-    /**
-     * Fall-over-dead timeout. If we do not make progress in this long, just fall over and propagate the failure.
-     * All users are expected to fail, possibly attempting to recover by restarting. It is fair to remain
-     * non-operational.
-     */
-    // TODO: maybe make this configurable somehow?
-    private static final Timeout DEAD_TIMEOUT = Timeout.apply(15, TimeUnit.MINUTES);
-
+    private final ConcurrentMap<Long, ShardState> backends = new ConcurrentHashMap<>();
     private final ActorContext actorContext;
-    // FIXME: this counter should be in superclass somewhere
-    private final AtomicLong nextSessionId = new AtomicLong();
-    private final Function1<ActorRef, ?> connectFunction;
 
     @GuardedBy("this")
     private long nextShard = 1;
@@ -70,21 +45,8 @@ final class ModuleShardBackendResolver extends BackendInfoResolver<ShardBackendI
 
     // FIXME: we really need just ActorContext.findPrimaryShardAsync()
     ModuleShardBackendResolver(final ClientIdentifier clientId, final ActorContext actorContext) {
+        super(clientId, actorContext);
         this.actorContext = Preconditions.checkNotNull(actorContext);
-        this.connectFunction = ExplicitAsk.toScala(t -> new ConnectClientRequest(clientId, t, ABIVersion.BORON,
-            ABIVersion.current()));
-    }
-
-    @Override
-    protected void invalidateBackendInfo(final CompletionStage<? extends BackendInfo> info) {
-        LOG.trace("Initiated invalidation of backend information {}", info);
-        info.thenAccept(this::invalidate);
-    }
-
-    private void invalidate(final BackendInfo result) {
-        Preconditions.checkArgument(result instanceof ShardBackendInfo);
-        LOG.debug("Invalidating backend information {}", result);
-        actorContext.getPrimaryShardInfoCache().remove(((ShardBackendInfo)result).getShardName());
     }
 
     Long resolveShardForPath(final YangInstanceIdentifier path) {
@@ -107,43 +69,70 @@ final class ModuleShardBackendResolver extends BackendInfoResolver<ShardBackendI
         return cookie;
     }
 
+
     @Override
-    protected CompletableFuture<ShardBackendInfo> resolveBackendInfo(final Long cookie) {
+    public CompletionStage<ShardBackendInfo> getBackendInfo(final Long cookie) {
+        /*
+         * We cannot perform a simple computeIfAbsent() here because we need to control sequencing of when the state
+         * is inserted into the map and retired from it (based on the stage result).
+         *
+         * We do not want to hook another stage one processing completes and hooking a removal on failure from a compute
+         * method runs the inherent risk of stage completing before the insertion does (i.e. we have a removal of
+         * non-existent element.
+         */
+        final ShardState existing = backends.get(cookie);
+        if (existing != null) {
+            return existing.getStage();
+        }
+
         final String shardName = shards.inverse().get(cookie);
         if (shardName == null) {
             LOG.warn("Failing request for non-existent cookie {}", cookie);
-            return NULL_FUTURE;
+            throw new IllegalArgumentException("Cookie " + cookie + " does not have a shard assigned");
         }
 
-        final CompletableFuture<ShardBackendInfo> ret = new CompletableFuture<>();
-
-        FutureConverters.toJava(actorContext.findPrimaryShardAsync(shardName)).thenCompose(info -> {
-            LOG.debug("Looking up primary info for {} from {}", shardName, info);
-            return FutureConverters.toJava(ExplicitAsk.ask(info.getPrimaryShardActor(), connectFunction, DEAD_TIMEOUT));
-        }).thenApply(response -> {
-            if (response instanceof RequestFailure) {
-                final RequestFailure<?, ?> failure = (RequestFailure<?, ?>) response;
-                LOG.debug("Connect request failed {}", failure, failure.getCause());
-                throw Throwables.propagate(failure.getCause());
-            }
+        LOG.debug("Resolving cookie {} to shard {}", cookie, shardName);
+        final ShardState toInsert = resolveBackendInfo(shardName, cookie);
 
-            LOG.debug("Resolved backend information to {}", response);
+        final ShardState raced = backends.putIfAbsent(cookie, toInsert);
+        if (raced != null) {
+            // We have had a concurrent insertion, return that
+            LOG.debug("Race during insertion of state for cookie {} shard {}", cookie, shardName);
+            return raced.getStage();
+        }
 
-            Preconditions.checkArgument(response instanceof ConnectClientSuccess, "Unhandled response {}", response);
-            final ConnectClientSuccess success = (ConnectClientSuccess) response;
+        // We have succeeded in populating the map, now we need to take care of pruning the entry if it fails to
+        // complete
+        final CompletionStage<ShardBackendInfo> stage = toInsert.getStage();
+        stage.whenComplete((info, failure) -> {
+            if (failure != null) {
+                LOG.debug("Resolution of cookie {} shard {} failed, removing state", cookie, shardName, failure);
+                backends.remove(cookie, toInsert);
 
-            return new ShardBackendInfo(success.getBackend(),
-                nextSessionId.getAndIncrement(), success.getVersion(), shardName, UnsignedLong.fromLongBits(cookie),
-                success.getDataTree(), success.getMaxMessages());
-        }).whenComplete((info, throwablw) -> {
-            if (throwablw != null) {
-                ret.completeExceptionally(throwablw);
-            } else {
-                ret.complete(info);
+                // Remove cache state in case someone else forgot to invalidate it
+                flushCache(shardName);
             }
         });
 
-        LOG.debug("Resolving cookie {} to shard {}", cookie, shardName);
-        return ret;
+        return stage;
+    }
+
+    @Override
+    public CompletionStage<ShardBackendInfo> refreshBackendInfo(final Long cookie,
+            final ShardBackendInfo staleInfo) {
+        final ShardState existing = backends.get(cookie);
+        if (existing != null) {
+            if (!staleInfo.equals(existing.getResult())) {
+                return existing.getStage();
+            }
+
+            LOG.debug("Invalidating backend information {}", staleInfo);
+            flushCache(staleInfo.getShardName());
+
+            LOG.trace("Invalidated cache %s", staleInfo);
+            backends.remove(cookie, existing);
+        }
+
+        return getBackendInfo(cookie);
     }
 }