import akka.actor.ActorRef;
import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.MoreObjects;
+import com.google.common.base.MoreObjects.ToStringHelper;
import com.google.common.base.Preconditions;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
import java.util.Optional;
@VisibleForTesting
static final long REQUEST_TIMEOUT_NANOS = TimeUnit.SECONDS.toNanos(30);
+ private static final FiniteDuration REQUEST_TIMEOUT_DURATION = FiniteDuration.apply(REQUEST_TIMEOUT_NANOS,
+ TimeUnit.NANOSECONDS);
+
private final Lock lock = new ReentrantLock();
private final ClientActorContext context;
@GuardedBy("lock")
private final TransmitQueue queue;
private final Long cookie;
+ @GuardedBy("lock")
+ private boolean haveTimer;
+
private volatile RequestException poisoned;
- private long lastProgress;
// Do not allow subclassing outside of this package
AbstractClientConnection(final ClientActorContext context, final Long cookie,
this.context = Preconditions.checkNotNull(context);
this.cookie = Preconditions.checkNotNull(cookie);
this.queue = Preconditions.checkNotNull(queue);
- this.lastProgress = readTime();
}
// Do not allow subclassing outside of this package
- AbstractClientConnection(final AbstractClientConnection<T> oldConnection) {
+ AbstractClientConnection(final AbstractClientConnection<T> oldConnection, final int targetQueueSize) {
this.context = oldConnection.context;
this.cookie = oldConnection.cookie;
- this.lastProgress = oldConnection.lastProgress;
- this.queue = new TransmitQueue.Halted();
+ this.queue = new TransmitQueue.Halted(targetQueueSize);
}
public final ClientActorContext context() {
return context.self();
}
+ public final long currentTime() {
+ return context.ticker().read();
+ }
+
/**
* Send a request to the backend and invoke a specified callback when it finishes. This method is safe to invoke
* from any thread.
*
+ * <p>This method may put the caller thread to sleep in order to throttle the request rate.
+ * The callback may be called before the sleep finishes.
+ *
* @param request Request to send
* @param callback Callback to invoke
*/
public final void sendRequest(final Request<?, ?> request, final Consumer<Response<?, ?>> callback) {
- final RequestException maybePoison = poisoned;
- if (maybePoison != null) {
- throw new IllegalStateException("Connection " + this + " has been poisoned", maybePoison);
- }
-
- final ConnectionEntry entry = new ConnectionEntry(request, callback, readTime());
-
- lock.lock();
+ final long now = currentTime();
+ final long delay = enqueueEntry(new ConnectionEntry(request, callback, now), now);
try {
- queue.enqueue(entry, entry.getEnqueuedTicks());
- } finally {
- lock.unlock();
+ TimeUnit.NANOSECONDS.sleep(delay);
+ } catch (InterruptedException e) {
+ Thread.currentThread().interrupt();
+ LOG.debug("Interrupted after sleeping {}ns", e, currentTime() - now);
}
}
+ /**
+ * Send a request to the backend and invoke a specified callback when it finishes. This method is safe to invoke
+ * from any thread.
+ *
+ * <p>
+ * Note that unlike {@link #sendRequest(Request, Consumer)}, this method does not exert backpressure, hence it
+ * should never be called from an application thread.
+ *
+ * @param request Request to send
+ * @param callback Callback to invoke
+ * @param enqueuedTicks Time (according to {@link #currentTime()} of request enqueue
+ */
+ public final void enqueueRequest(final Request<?, ?> request, final Consumer<Response<?, ?>> callback,
+ final long enqueuedTicks) {
+ enqueueEntry(new ConnectionEntry(request, callback, enqueuedTicks), currentTime());
+ }
+
public abstract Optional<T> getBackendInfo();
final Iterable<ConnectionEntry> startReplay() {
@GuardedBy("lock")
final void finishReplay(final ReconnectForwarder forwarder) {
- queue.setForwarder(forwarder, readTime());
+ setForwarder(forwarder);
lock.unlock();
}
@GuardedBy("lock")
final void setForwarder(final ReconnectForwarder forwarder) {
- queue.setForwarder(forwarder, readTime());
+ queue.setForwarder(forwarder, currentTime());
}
@GuardedBy("lock")
- abstract ClientActorBehavior<T> reconnectConnection(ClientActorBehavior<T> current);
+ abstract ClientActorBehavior<T> lockedReconnect(ClientActorBehavior<T> current);
- private long readTime() {
- return context.ticker().read();
+ final long enqueueEntry(final ConnectionEntry entry, final long now) {
+ lock.lock();
+ try {
+ final RequestException maybePoison = poisoned;
+ if (maybePoison != null) {
+ throw new IllegalStateException("Connection " + this + " has been poisoned", maybePoison);
+ }
+
+ if (queue.isEmpty()) {
+ // The queue is becoming non-empty, schedule a timer
+ scheduleTimer(REQUEST_TIMEOUT_DURATION);
+ }
+ return queue.enqueue(entry, now);
+ } finally {
+ lock.unlock();
+ }
}
- final void enqueueEntry(final ConnectionEntry entry, final long now) {
+ final ClientActorBehavior<T> reconnect(final ClientActorBehavior<T> current) {
lock.lock();
try {
- queue.enqueue(entry, now);
+ return lockedReconnect(current);
} finally {
lock.unlock();
}
*
* @param delay Delay, in nanoseconds
*/
+ @GuardedBy("lock")
private void scheduleTimer(final FiniteDuration delay) {
+ if (haveTimer) {
+ LOG.debug("{}: timer already scheduled", context.persistenceId());
+ return;
+ }
+ if (queue.hasSuccessor()) {
+ LOG.debug("{}: connection has successor, not scheduling timer", context.persistenceId());
+ return;
+ }
LOG.debug("{}: scheduling timeout in {}", context.persistenceId(), delay);
context.executeInActor(this::runTimer, delay);
+ haveTimer = true;
}
/**
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;
- }
+ haveTimer = false;
+ final long now = currentTime();
+ // The following line is only reliable when queue is not forwarding, but such state should not last long.
+ final long ticksSinceProgress = queue.ticksStalling(now);
+ 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.
delay = lockedCheckTimeout(now);
if (delay == null) {
// We have timed out. There is no point in scheduling a timer
- return reconnectConnection(current);
+ return lockedReconnect(current);
+ }
+
+ if (delay.isPresent()) {
+ // If there is new delay, schedule a timer
+ scheduleTimer(delay.get());
}
} finally {
lock.unlock();
}
- if (delay.isPresent()) {
- // If there is new delay, schedule a timer
- scheduleTimer(delay.get());
- }
-
return current;
}
return Optional.empty();
}
- final long delay = head.getEnqueuedTicks() - now + REQUEST_TIMEOUT_NANOS;
- if (delay <= 0) {
- LOG.debug("Connection {} timed out", this);
+ final long beenOpen = now - head.getEnqueuedTicks();
+ if (beenOpen >= REQUEST_TIMEOUT_NANOS) {
+ LOG.debug("Connection {} has a request not completed for {} nanoseconds, timing out", this, beenOpen);
return null;
}
- return Optional.of(FiniteDuration.apply(delay, TimeUnit.NANOSECONDS));
+ return Optional.of(FiniteDuration.apply(REQUEST_TIMEOUT_NANOS - beenOpen, TimeUnit.NANOSECONDS));
}
final void poison(final RequestException cause) {
}
final void receiveResponse(final ResponseEnvelope<?> envelope) {
- final long now = readTime();
+ final long now = currentTime();
+ final Optional<TransmittedConnectionEntry> maybeEntry;
lock.lock();
try {
- queue.complete(envelope, now);
+ maybeEntry = queue.complete(envelope, now);
} finally {
lock.unlock();
}
- lastProgress = readTime();
+ if (maybeEntry.isPresent()) {
+ final TransmittedConnectionEntry entry = maybeEntry.get();
+ LOG.debug("Completing {} with {}", entry, envelope);
+ entry.complete(envelope.getMessage());
+ }
+ }
+
+ @Override
+ public final String toString() {
+ return addToStringAttributes(MoreObjects.toStringHelper(this).omitNullValues()).toString();
+ }
+
+ ToStringHelper addToStringAttributes(final ToStringHelper toStringHelper) {
+ return toStringHelper.add("client", context.getIdentifier()).add("cookie", cookie).add("poisoned", poisoned);
}
}
Code Review / controller.git / blobdiff