import akka.actor.ActorRef;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
-import com.google.common.base.Verify;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
-import java.util.ArrayDeque;
import java.util.Optional;
-import java.util.Queue;
import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
import java.util.function.Consumer;
import javax.annotation.Nonnull;
import javax.annotation.concurrent.GuardedBy;
@VisibleForTesting
static final long REQUEST_TIMEOUT_NANOS = TimeUnit.SECONDS.toNanos(30);
- private final Queue<ConnectionEntry> pending;
+ private final Lock lock = new ReentrantLock();
private final ClientActorContext context;
+ @GuardedBy("lock")
+ private final TransmitQueue queue;
private final Long cookie;
- private volatile ReconnectForwarder successor;
- private volatile RequestException poisoned;
+ // Updated from actor thread only
private long lastProgress;
- private AbstractClientConnection(final ClientActorContext context, final Long cookie,
- final Queue<ConnectionEntry> pending) {
+ private volatile RequestException poisoned;
+
+ // Do not allow subclassing outside of this package
+ AbstractClientConnection(final ClientActorContext context, final Long cookie,
+ final TransmitQueue queue) {
this.context = Preconditions.checkNotNull(context);
this.cookie = Preconditions.checkNotNull(cookie);
- this.pending = Preconditions.checkNotNull(pending);
+ this.queue = Preconditions.checkNotNull(queue);
this.lastProgress = readTime();
}
- // Do not allow subclassing outside of this package
- AbstractClientConnection(final ClientActorContext context, final Long cookie) {
- this(context, cookie, new ArrayDeque<>(1));
- }
-
// Do not allow subclassing outside of this package
AbstractClientConnection(final AbstractClientConnection<T> oldConnection) {
- this(oldConnection.context, oldConnection.cookie, oldConnection.pending);
+ this.context = oldConnection.context;
+ this.cookie = oldConnection.cookie;
+ this.lastProgress = oldConnection.lastProgress;
+ this.queue = new TransmitQueue.Halted();
}
public final ClientActorContext context() {
return context.self();
}
- final long readTime() {
- return context.ticker().read();
- }
-
- final Queue<ConnectionEntry> pending() {
- return pending;
- }
-
/**
* Send a request to the backend and invoke a specified callback when it finishes. This method is safe to invoke
* from any thread.
* @param callback Callback to invoke
*/
public final void sendRequest(final Request<?, ?> request, final Consumer<Response<?, ?>> callback) {
- Preconditions.checkState(poisoned == null, "Connection %s has been poisoned", this);
-
- final ReconnectForwarder beforeQueue = successor;
- final ConnectionEntry entry = new ConnectionEntry(request, callback, readTime());
- if (beforeQueue != null) {
- LOG.trace("Forwarding entry {} from {} to {}", entry, this, beforeQueue);
- beforeQueue.forwardEntry(entry);
- return;
+ final RequestException maybePoison = poisoned;
+ if (maybePoison != null) {
+ throw new IllegalStateException("Connection " + this + " has been poisoned", maybePoison);
}
- enqueueEntry(entry);
+ final ConnectionEntry entry = new ConnectionEntry(request, callback, readTime());
- final ReconnectForwarder afterQueue = successor;
- if (afterQueue != null) {
- synchronized (this) {
- spliceToSuccessor(afterQueue);
- }
+ lock.lock();
+ try {
+ queue.enqueue(entry, entry.getEnqueuedTicks());
+ } finally {
+ lock.unlock();
}
}
- public final synchronized void setForwarder(final ReconnectForwarder forwarder) {
- Verify.verify(successor == null, "Successor {} already set on connection {}", successor, this);
- successor = Preconditions.checkNotNull(forwarder);
- LOG.debug("Connection {} superseded by {}, splicing queue", this, successor);
- spliceToSuccessor(forwarder);
+ public abstract Optional<T> getBackendInfo();
+
+ final Iterable<ConnectionEntry> startReplay() {
+ lock.lock();
+ return queue.asIterable();
}
- public abstract Optional<T> getBackendInfo();
+ @GuardedBy("lock")
+ final void finishReplay(final ReconnectForwarder forwarder) {
+ queue.setForwarder(forwarder, readTime());
+ lock.unlock();
+ }
- @GuardedBy("this")
- void spliceToSuccessor(final ReconnectForwarder successor) {
- ConnectionEntry entry = pending.poll();
- while (entry != null) {
- successor.forwardEntry(entry);
- entry = pending.poll();
- }
+ @GuardedBy("lock")
+ final void setForwarder(final ReconnectForwarder forwarder) {
+ queue.setForwarder(forwarder, readTime());
}
- final ConnectionEntry dequeEntry() {
- lastProgress = readTime();
- return pending.poll();
+ @GuardedBy("lock")
+ abstract ClientActorBehavior<T> reconnectConnection(ClientActorBehavior<T> current);
+
+ private long readTime() {
+ return context.ticker().read();
}
- void enqueueEntry(final ConnectionEntry entry) {
- pending.add(entry);
+ final void enqueueEntry(final ConnectionEntry entry, final long now) {
+ lock.lock();
+ try {
+ queue.enqueue(entry, now);
+ } finally {
+ lock.unlock();
+ }
}
/**
*/
@VisibleForTesting
final ClientActorBehavior<T> runTimer(final ClientActorBehavior<T> current) {
- final long now = readTime();
-
- if (!isEmpty()) {
- final long ticksSinceProgress = now - lastProgress;
- if (ticksSinceProgress >= NO_PROGRESS_TIMEOUT_NANOS) {
- LOG.error("Queue {} has not seen progress in {} seconds, failing all requests", this,
- TimeUnit.NANOSECONDS.toSeconds(ticksSinceProgress));
-
- poison(new NoProgressException(ticksSinceProgress));
- current.removeConnection(this);
- return current;
+ final Optional<FiniteDuration> delay;
+
+ lock.lock();
+ try {
+ final long now = readTime();
+ if (!queue.isEmpty()) {
+ final long ticksSinceProgress = now - lastProgress;
+ if (ticksSinceProgress >= NO_PROGRESS_TIMEOUT_NANOS) {
+ LOG.error("Queue {} has not seen progress in {} seconds, failing all requests", this,
+ TimeUnit.NANOSECONDS.toSeconds(ticksSinceProgress));
+
+ lockedPoison(new NoProgressException(ticksSinceProgress));
+ current.removeConnection(this);
+ return current;
+ }
}
- }
- // Requests are always scheduled in sequence, hence checking for timeout is relatively straightforward.
- // Note we use also inquire about the delay, so we can re-schedule if needed, hence the unusual tri-state
- // return convention.
- final Optional<FiniteDuration> delay = checkTimeout(now);
- if (delay == null) {
- // We have timed out. There is no point in scheduling a timer
- return reconnectConnection(current);
+ // Requests are always scheduled in sequence, hence checking for timeout is relatively straightforward.
+ // Note we use also inquire about the delay, so we can re-schedule if needed, hence the unusual tri-state
+ // return convention.
+ delay = lockedCheckTimeout(now);
+ if (delay == null) {
+ // We have timed out. There is no point in scheduling a timer
+ return reconnectConnection(current);
+ }
+ } finally {
+ lock.unlock();
}
if (delay.isPresent()) {
return current;
}
- boolean isEmpty() {
- return pending.isEmpty();
+ @VisibleForTesting
+ final Optional<FiniteDuration> checkTimeout(final long now) {
+ lock.lock();
+ try {
+ return lockedCheckTimeout(now);
+ } finally {
+ lock.unlock();
+ }
}
/*
*/
@SuppressFBWarnings(value = "NP_OPTIONAL_RETURN_NULL",
justification = "Returning null Optional is documented in the API contract.")
- final Optional<FiniteDuration> checkTimeout(final ConnectionEntry head, final long now) {
+ @GuardedBy("lock")
+ private Optional<FiniteDuration> lockedCheckTimeout(final long now) {
+ final ConnectionEntry head = queue.peek();
if (head == null) {
return Optional.empty();
}
return Optional.of(FiniteDuration.apply(delay, TimeUnit.NANOSECONDS));
}
- /*
- * We are using tri-state return here to indicate one of three conditions:
- * - if there is no timeout to schedule, return Optional.empty()
- * - if there is a timeout to schedule, return a non-empty optional
- * - if this connections has timed out, return null
- */
- @SuppressFBWarnings(value = "NP_OPTIONAL_RETURN_NULL",
- justification = "Returning null Optional is documented in the API contract.")
- Optional<FiniteDuration> checkTimeout(final long now) {
- return checkTimeout(pending.peek(), now);
- }
-
- static void poisonQueue(final Queue<? extends ConnectionEntry> queue, final RequestException cause) {
- for (ConnectionEntry e : queue) {
- final Request<?, ?> request = e.getRequest();
- LOG.trace("Poisoning request {}", request, cause);
- e.complete(request.toRequestFailure(cause));
+ final void poison(final RequestException cause) {
+ lock.lock();
+ try {
+ lockedPoison(cause);
+ } finally {
+ lock.unlock();
}
- queue.clear();
}
- void poison(final RequestException cause) {
+ @GuardedBy("lock")
+ private void lockedPoison(final RequestException cause) {
poisoned = cause;
- poisonQueue(pending, cause);
+ queue.poison(cause);
}
@VisibleForTesting
return poisoned;
}
- abstract ClientActorBehavior<T> reconnectConnection(ClientActorBehavior<T> current);
+ final void receiveResponse(final ResponseEnvelope<?> envelope) {
+ final long now = readTime();
- abstract void receiveResponse(final ResponseEnvelope<?> envelope);
+ final Optional<TransmittedConnectionEntry> maybeEntry;
+ lock.lock();
+ try {
+ maybeEntry = queue.complete(envelope, now);
+ } finally {
+ lock.unlock();
+ }
+
+ if (maybeEntry.isPresent()) {
+ final TransmittedConnectionEntry entry = maybeEntry.get();
+ LOG.debug("Completing {} with {}", entry, envelope);
+ entry.complete(envelope.getMessage());
+ }
+
+ lastProgress = readTime();
+ }
}
Code Review / controller.git / blobdiff