@Override
public void run() {
InetAddress[] inetAddrs;
Listener savedListener;
synchronized (DnsNameResolver.this) {
// If this task is started by refresh(), there might already be a scheduled task.
if (resolutionTask != null) {
resolutionTask.cancel(false);
resolutionTask = null;
}
if (shutdown) {
return;
}
savedListener = listener;
resolving = true;
}
try {
try {
inetAddrs = getAllByName(host);
} catch (UnknownHostException e) {
synchronized (DnsNameResolver.this) {
if (shutdown) {
return;
}
// Because timerService is the single-threaded GrpcUtil.TIMER_SERVICE in production,
// we need to delegate the blocking work to the executor
resolutionTask =
timerService.schedule(
new LogExceptionRunnable(resolutionRunnableOnExecutor),
1,
TimeUnit.MINUTES);
}
savedListener.onError(Status.UNAVAILABLE.withCause(e));
return;
}
ResolvedServerInfoGroup.Builder servers = ResolvedServerInfoGroup.builder();
for (int i = 0; i < inetAddrs.length; i++) {
InetAddress inetAddr = inetAddrs[i];
servers.add(
new ResolvedServerInfo(new InetSocketAddress(inetAddr, port), Attributes.EMPTY));
}
savedListener.onUpdate(Collections.singletonList(servers.build()), Attributes.EMPTY);
} finally {
synchronized (DnsNameResolver.this) {
resolving = false;
}
}
}
@Test
public void verifyFailFastAndNonFailFastBehaviors() {
int pendingStreamsCount = 0;
int failFastPendingStreamsCount = 0;
final SocketAddress addr1 = mock(SocketAddress.class);
final SocketAddress addr2 = mock(SocketAddress.class);
createTransportSet(addr1, addr2);
final DelayedClientTransport delayedTransport =
(DelayedClientTransport) transportSet.obtainActiveTransport();
assertEquals(ConnectivityState.CONNECTING, transportSet.getState(false));
assertFalse(delayedTransport.isInBackoffPeriod());
// Create a new fail fast stream.
ClientStream ffStream =
delayedTransport.newStream(method, headers, failFastCallOptions, statsTraceCtx);
ffStream.start(mockStreamListener);
// Verify it is queued.
assertEquals(++pendingStreamsCount, delayedTransport.getPendingStreamsCount());
failFastPendingStreamsCount++;
// Create a new non fail fast stream.
delayedTransport.newStream(method, headers, waitForReadyCallOptions, statsTraceCtx);
// Verify it is queued.
assertEquals(++pendingStreamsCount, delayedTransport.getPendingStreamsCount());
// Let this 1st address fail without success.
transports.poll().listener.transportShutdown(Status.UNAVAILABLE);
assertEquals(ConnectivityState.CONNECTING, transportSet.getState(false));
assertFalse(delayedTransport.isInBackoffPeriod());
// Verify pending streams still in queue.
assertEquals(pendingStreamsCount, delayedTransport.getPendingStreamsCount());
// Create a new fail fast stream.
delayedTransport.newStream(method, headers, failFastCallOptions, statsTraceCtx);
// Verify it is queued.
assertEquals(++pendingStreamsCount, delayedTransport.getPendingStreamsCount());
failFastPendingStreamsCount++;
// Create a new non fail fast stream
delayedTransport.newStream(method, headers, waitForReadyCallOptions, statsTraceCtx);
// Verify it is queued.
assertEquals(++pendingStreamsCount, delayedTransport.getPendingStreamsCount());
// Let this 2nd address fail without success.
Status failureStatus = Status.UNAVAILABLE.withDescription("some unique failure");
transports.poll().listener.transportShutdown(failureStatus);
assertEquals(ConnectivityState.TRANSIENT_FAILURE, transportSet.getState(false));
assertTrue(delayedTransport.isInBackoffPeriod());
// Fail fast pending streams should be cleared
assertEquals(
pendingStreamsCount - failFastPendingStreamsCount,
delayedTransport.getPendingStreamsCount());
pendingStreamsCount -= failFastPendingStreamsCount;
failFastPendingStreamsCount = 0;
fakeExecutor.runDueTasks();
verify(mockStreamListener).closed(same(failureStatus), any(Metadata.class));
// Create a new fail fast stream.
delayedTransport.newStream(method, headers, failFastCallOptions, statsTraceCtx);
// Verify it is not queued.
assertEquals(pendingStreamsCount, delayedTransport.getPendingStreamsCount());
// Create a new non fail fast stream
delayedTransport.newStream(method, headers, waitForReadyCallOptions, statsTraceCtx);
// Verify it is queued.
assertEquals(++pendingStreamsCount, delayedTransport.getPendingStreamsCount());
fakeClock.forwardMillis(10);
// Now back-off is over
assertEquals(ConnectivityState.CONNECTING, transportSet.getState(false));
assertFalse(delayedTransport.isInBackoffPeriod());
// Create a new fail fast stream.
delayedTransport.newStream(method, headers, failFastCallOptions, statsTraceCtx);
// Verify it is queued.
assertEquals(++pendingStreamsCount, delayedTransport.getPendingStreamsCount());
failFastPendingStreamsCount++;
assertEquals(1, failFastPendingStreamsCount);
fakeExecutor.runDueTasks(); // Drain new 'real' stream creation; not important to this test.
}