Using java jmx over rmi with remote docker container. MIT licensed :)

DockerHackfixRMISocketFactory.java

import com.github.dockerjava.api.command.InspectContainerResponse;
import com.github.dockerjava.api.model.Container;
import com.github.dockerjava.api.model.ContainerNetwork;
import com.github.dockerjava.api.model.ContainerPort;
import lombok.SneakyThrows;
import lombok.experimental.Delegate;
import java.util.*;

/**
 * init asap with utils.DockerHackfixRMISocketFactory#init(), then target container run using env var
 * JAVA_TOOL_OPTIONS="-Dcom.sun.management.jmxremote=true -Dcom.sun.management.jmxremote.local.only=false -Dcom.sun.management.jmxremote.port=9001 -Dcom.sun.management.jmxremote.rmi.port=9001"
 */
@Slf4j
final class DockerHackfixRMISocketFactory extends RMISocketFactory {

    @Delegate(types = RMIServerSocketFactory.class)
    private final RMISocketFactory socketFactory = RMISocketFactory.getDefaultSocketFactory();

    @Override
    public Socket createSocket(String host, int port) throws IOException {
        DockerClientFactory docker = DockerClientFactory.instance();
        String dockerHostIpAddress = docker.dockerHostIpAddress();
        if (dockerHostIpAddress.equals(host)) {
            log.debug("Making initial connection to {}:{}", dockerHostIpAddress, port);
            return socketFactory.createSocket(host, port);
        }
        log.debug("try to translate {}:{} that comes from the jmx server", host, port);
        int publicJmxPort = docker.client().listContainersCmd().exec().stream()
                .filter(container -> container.getNetworkSettings().getNetworks().values().stream().map(ContainerNetwork::getIpAddress).anyMatch(host::equals))
                .map(Container::getPorts)
                .flatMap(Stream::of)
                .filter(containerPort -> Objects.equals(containerPort.getPrivatePort(), port))
                .map(ContainerPort::getPublicPort)
                .findFirst()
                .orElseThrow(() -> new IllegalStateException("No container found for " + host + ':' + port));
        log.debug("connecting to {}:{}", dockerHostIpAddress, publicJmxPort);
        return socketFactory.createSocket(dockerHostIpAddress, publicJmxPort);
    }

    @SneakyThrows
    public static void init() {
        RMISocketFactory.setSocketFactory(new DockerHackfixRMISocketFactory());
    }

}