[Bug] Additional `clientlib` JARs can conflict with required dependencies

[andrewazores]

After loading a WildFly jboss-client.jar into clientlib in order to enable remote+http JMX connections, my Cryostat instance became unable to query the Podman API:

May 31, 2023 2:38:55 PM io.cryostat.core.log.Logger error
SEVERE: Podman API request failed
java.lang.IllegalArgumentException: The Vertx instance must be created with the preferNativeTransport option set to true to create domain sockets
	at io.vertx.core.net.impl.transport.Transport.channelFactory(Transport.java:183)
	at io.vertx.core.net.impl.ChannelProvider.connect(ChannelProvider.java:98)
	at io.vertx.core.net.impl.ChannelProvider.connect(ChannelProvider.java:92)
	at io.vertx.core.net.impl.NetClientImpl.connectInternal2(NetClientImpl.java:273)
	at io.vertx.core.net.impl.NetClientImpl.lambda$connectInternal$1(NetClientImpl.java:240)
	at io.vertx.core.impl.future.FutureImpl$3.onSuccess(FutureImpl.java:141)
	at io.vertx.core.impl.future.FutureBase.lambda$emitSuccess$0(FutureBase.java:54)
	at io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:174)
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:167)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:470)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:569)
	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
	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)

With a bit of additional digging and logging added, I came to this:

INFO: isNativeTransportEnabled? false
Jun 01, 2023 2:36:16 PM io.cryostat.core.log.Logger info
INFO: Epoll.isAvailable? false
java.lang.ExceptionInInitializerError
        at io.netty.channel.epoll.Epoll.<clinit>(Epoll.java:40)
        at io.vertx.core.net.impl.transport.EpollTransport.isAvailable(EpollTransport.java:86)
        at io.vertx.core.net.impl.transport.Transport.nativeTransport(Transport.java:59)
        at io.vertx.core.net.impl.transport.Transport.transport(Transport.java:82)
        at io.vertx.core.impl.VertxBuilder.initTransport(VertxBuilder.java:327)
        at io.vertx.core.impl.VertxBuilder.init(VertxBuilder.java:265)
        at io.vertx.core.Vertx.vertx(Vertx.java:87)
        at io.cryostat.net.NetworkModule.provideVertx(NetworkModule.java:169)
        at io.cryostat.net.NetworkModule_ProvideVertxFactory.provideVertx(NetworkModule_ProvideVertxFactory.java:35)
        at io.cryostat.net.NetworkModule_ProvideVertxFactory.get(NetworkModule_ProvideVertxFactory.java:27)
        at io.cryostat.net.NetworkModule_ProvideVertxFactory.get(NetworkModule_ProvideVertxFactory.java:1)
        at dagger.internal.DoubleCheck.get(DoubleCheck.java:47)
        at io.cryostat.DaggerCryostat_Client$ClientImpl.vertx(DaggerCryostat_Client.java:1712)
        at io.cryostat.Cryostat.main(Cryostat.java:154)
Caused by: java.lang.IllegalStateException: Multiple resources found for 'META-INF/native/libnetty_transport_native_epoll_x86_64.so' with different content: [jar:file:/app/libs/netty-transport-native-epoll-4.1.86.Final-linux-x86_64.jar!/M
ETA-INF/native/libnetty_transport_native_epoll_x86_64.so, jar:file:/clientlib/jboss-client.jar!/META-INF/native/libnetty_transport_native_epoll_x86_64.so]
        at io.netty.util.internal.NativeLibraryLoader.getResource(NativeLibraryLoader.java:301)
        at io.netty.util.internal.NativeLibraryLoader.load(NativeLibraryLoader.java:173)
        at io.netty.channel.epoll.Native.loadNativeLibrary(Native.java:323)
        at io.netty.channel.epoll.Native.<clinit>(Native.java:85)
        ... 14 more

In the case that additional JARs added to the clientlib conflict with Cryostat's own required dependencies, strange behaviours may result.