Getting ChannelException when adding Google cloud client library to Play 2.5

Question

Here is some of the stack trace

io.netty.channel.ChannelException: Unable to create Channel from class class io.netty.channel.socket.nio.NioServerSocketChannel
at io.netty.channel.ReflectiveChannelFactory.newChannel(ReflectiveChannelFactory.java:41)
at io.netty.bootstrap.AbstractBootstrap.initAndRegister(AbstractBootstrap.java:318)
at io.netty.bootstrap.AbstractBootstrap.doBind(AbstractBootstrap.java:282)
at io.netty.bootstrap.AbstractBootstrap.bind(AbstractBootstrap.java:246)
at play.core.server.NettyServer.bind(NettyServer.scala:139)
at play.core.server.NettyServer.play$core$server$NettyServer$$bindChannel(NettyServer.scala:224)
at play.core.server.NettyServer$$anonfun$1.apply(NettyServer.scala:216)
at play.core.server.NettyServer$$anonfun$1.apply(NettyServer.scala:216)
at scala.Option.map(Option.scala:146)
at play.core.server.NettyServer.<init>(NettyServer.scala:216)
at play.core.server.NettyServerProvider.createServer(NettyServer.scala:279)
at play.core.server.NettyServerProvider.createServer(NettyServer.scala:278)
at play.core.server.DevServerStart$$anonfun$mainDev$1.apply(DevServerStart.scala:235)
at play.core.server.DevServerStart$$anonfun$mainDev$1.apply(DevServerStart.scala:65)
at play.utils.Threads$.withContextClassLoader(Threads.scala:21)
at play.core.server.DevServerStart$.mainDev(DevServerStart.scala:64)
at play.core.server.DevServerStart$.mainDevHttpMode(DevServerStart.scala:54)
at play.core.server.DevServerStart.mainDevHttpMode(DevServerStart.scala)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at play.runsupport.Reloader$.startDevMode(Reloader.scala:234)
at play.sbt.run.PlayRun$$anonfun$playRunTask$1$$anonfun$apply$2$$anonfun$apply$3.devModeServer$lzycompute$1(PlayRun.scala:74)
at play.sbt.run.PlayRun$$anonfun$playRunTask$1$$anonfun$apply$2$$anonfun$apply$3.play$sbt$run$PlayRun$$anonfun$$anonfun$$anonfun$$devModeServer$1(PlayRun.scala:74)
at play.sbt.run.PlayRun$$anonfun$playRunTask$1$$anonfun$apply$2$$anonfun$apply$3.apply(PlayRun.scala:100)
at play.sbt.run.PlayRun$$anonfun$playRunTask$1$$anonfun$apply$2$$anonfun$apply$3.apply(PlayRun.scala:53)
at scala.Function1$$anonfun$compose$1.apply(Function1.scala:47)
Caused by: java.lang.NoSuchMethodError: io.netty.channel.DefaultChannelId.newInstance()Lio/netty/channel/DefaultChannelId;

I added the depedency like this in my build.sbt file

libraryDependencies += "com.google.cloud" % "google-cloud" % "0.3.0"

This only happens when I add the Google cloud library. I'm not sure if this is a problem with the library or the framework

Answer 1

The version of netty that google-cloud uses conflicts with the version of netty that Play uses. This will exclude google-cloud's netty in favor of Play's.

libraryDependencies += ("com.google.cloud" % "google-cloud" % "0.3.0").excludeAll(ExclusionRule(organization = "io.netty"))

However if you try to use a feature which needs gRPC it'll fail. Details:

https://groups.google.com/forum/#!topic/play-framework/UUDZZRpAv3w https://github.com/playframework/netty-reactive-streams/pull/17

There are two solutions:

A. Downgrading google-cloud to 0.2.2 which you can do by renaming the artifact to gcloud-java:

"com.google.cloud" % "gcloud-java" % "0.2.2"

B. Downgrading Play back to 2.4.6