grpc calls failing after upgrading to 1.47.0

Hi all,

After upgrading to grpc version 1.47.0, our program stopped working. The usage scenario is very simple: we create a ManagedChannel via: NettyChannelBuilder.forAddress(getHost(), getPort()).defaultLoadBalancingPolicy("round_robin").usePlaintext().build(). We then create the stub simply by using newBlockingStub(). Using the stub results in the below error.

Caused by: io.netty.channel.AbstractChannel$AnnotatedConnectException: connect(..) failed: Address family not supported by protocol: /abc.xyz:50051
Caused by: java.net.ConnectException: connect(..) failed: Address family not supported by protocol
        at io.netty.channel.unix.Errors.newConnectException0(Errors.java:155)
        at io.netty.channel.unix.Errors.handleConnectErrno(Errors.java:128)
        at io.netty.channel.unix.Socket.connect(Socket.java:312)
        at io.netty.channel.epoll.AbstractEpollChannel.doConnect0(AbstractEpollChannel.java:773)
        at io.netty.channel.epoll.EpollSocketChannel.doConnect0(EpollSocketChannel.java:138)
        at io.netty.channel.epoll.AbstractEpollChannel.doConnect(AbstractEpollChannel.java:758)
        at io.netty.channel.epoll.AbstractEpollChannel$AbstractEpollUnsafe.connect(AbstractEpollChannel.java:600)
        at io.netty.channel.DefaultChannelPipeline$HeadContext.connect(DefaultChannelPipeline.java:1342)
        at io.netty.channel.AbstractChannelHandlerContext.invokeConnect(AbstractChannelHandlerContext.java:548)
        at io.netty.channel.AbstractChannelHandlerContext.connect(AbstractChannelHandlerContext.java:533)
        at io.netty.channel.ChannelDuplexHandler.connect(ChannelDuplexHandler.java:54)
        at io.grpc.netty.WriteBufferingAndExceptionHandler.connect(WriteBufferingAndExceptionHandler.java:157)
        at io.netty.channel.AbstractChannelHandlerContext.invokeConnect(AbstractChannelHandlerContext.java:548)
        at io.netty.channel.AbstractChannelHandlerContext.connect(AbstractChannelHandlerContext.java:533)
        at io.netty.channel.AbstractChannelHandlerContext.connect(AbstractChannelHandlerContext.java:517)
        at io.netty.channel.AbstractChannelHandlerContext.connect(AbstractChannelHandlerContext.java:457)
        at io.netty.channel.DefaultChannelPipeline.connect(DefaultChannelPipeline.java:942)
        at io.netty.channel.AbstractChannel.connect(AbstractChannel.java:229)
        at io.grpc.netty.NettyClientTransport.start(NettyClientTransport.java:306)
        at io.grpc.internal.ForwardingConnectionClientTransport.start(ForwardingConnectionClientTransport.java:34)
        at io.grpc.internal.ForwardingConnectionClientTransport.start(ForwardingConnectionClientTransport.java:34)
        at io.grpc.internal.InternalSubchannel.startNewTransport(InternalSubchannel.java:259)
        at io.grpc.internal.InternalSubchannel.access$400(InternalSubchannel.java:66)
        at io.grpc.internal.InternalSubchannel$1EndOfCurrentBackoff.run(InternalSubchannel.java:280)
        at io.grpc.SynchronizationContext$ManagedRunnable.run(SynchronizationContext.java:182)
        at io.grpc.SynchronizationContext.drain(SynchronizationContext.java:95)
        at io.grpc.SynchronizationContext.execute(SynchronizationContext.java:127)
        at io.grpc.SynchronizationContext$1.run(SynchronizationContext.java:155)
        at io.netty.util.concurrent.PromiseTask.runTask(PromiseTask.java:98)
        at io.netty.util.concurrent.ScheduledFutureTask.run(ScheduledFutureTask.java:170)
        at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164)
        at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:469)
        at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:384)
        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:986)
        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.base/java.lang.Thread.run(Thread.java:833)

After downgrading back to 1.45.1, the issue went away. Note that in the above example, abc.xyz is a simple dns address for a k8s service that has multiple replicas behind it.

[kgreav]

For those using maven shade plugin:

<configuration>
    <transformers>
        <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
    </transformers>
<configuration>

ref: Concatenating Service Entries with the ServicesResourceTransformer

[pikatenor]

I have experienced a slightly similar problem - are you deploying fat-JAR using plugins like Maven Assembly plugin or Gradle Shadow plugin? If so, you probably need to do proper merging of the provider-configuration files (META-INF/services/io.grpc.NameResolverProvider) .

ref. #9367