redis.embedded.core.PortProvider Maven / Gradle / Ivy

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package redis.embedded.core;

import java.io.IOException;
import java.net.ServerSocket;
import java.util.Collection;
import java.util.Iterator;
import java.util.concurrent.atomic.AtomicInteger;

public interface PortProvider {
    //Redis uses a cluster bus port as the first node port + 10000, so we need to make sure we use ports lower than
    // 55535 to ensure we always get a valid cluster bus port. We chose 50000 in order to have a safe margin.
    // Theoretically we could use the "cluster-port" as documented here:
    // https://redis.io/docs/reference/cluster-spec/#the-cluster-bus
    // however adding that config to the redis server currently results in an error when running on Windows.
    int REDIS_CLUSTER_MAX_PORT_EXCLUSIVE = 50000;

    int get();

    static PortProvider newEphemeralPortProvider() {
        return () -> {
            try (final ServerSocket socket = new ServerSocket(0)) {
                socket.setReuseAddress(false);
                return socket.getLocalPort();
            } catch (IOException e) {
                throw new IllegalArgumentException("Could not provide ephemeral port", e);
            }
        };
    }

    static PortProvider newEphemeralPortProviderInRedisClusterRange() {
        final PortProvider ephemeralPortProvider = newEphemeralPortProvider();
        return () -> {
            int port = ephemeralPortProvider.get();
            while (port > REDIS_CLUSTER_MAX_PORT_EXCLUSIVE) { port = ephemeralPortProvider.get();}
            return port;
        };
    }

    static PortProvider newPredefinedPortProvider(final Collection ports) {
        final Iterator iterator = ports.iterator();
        return () -> {
            if (!iterator.hasNext())
                throw new IllegalArgumentException("Ran out of Redis ports");
            return iterator.next();
        };
    }

    static PortProvider newSequencePortProvider() {
        return newSequencePortProvider(26379);
    }

    static PortProvider newSequencePortProvider(final int start) {
        final AtomicInteger currentPort = new AtomicInteger(start);
        return currentPort::getAndIncrement;
    }
}