RabbitMQUtils.java

package io.lumify.model.rabbitmq;

import com.rabbitmq.client.Address;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import io.lumify.core.config.Configuration;
import io.lumify.core.exception.LumifyException;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import static com.google.common.base.Preconditions.checkNotNull;

public class RabbitMQUtils {
    private static final String RABBITMQ_ADDR_PREFIX = "rabbitmq.addr";
    private static final int DEFAULT_PORT = 5672;

    public static Channel openChannel(Connection connection) {
        try {
            return connection.createChannel();
        } catch (IOException ex) {
            throw new LumifyException("Could not open channel to RabbitMQ", ex);
        }
    }

    public static Connection openConnection(Configuration configuration) throws IOException {
        ConnectionFactory factory = new ConnectionFactory();
        Address[] addresses = getAddresses(configuration);
        if (addresses.length == 0) {
            throw new LumifyException("Could not configure RabbitMQ. No addresses specified. expecting configuration parameter 'rabbitmq.addr.0.host'.");
        }
        return factory.newConnection(addresses);
    }

    private static Address[] getAddresses(Configuration configuration) {
        List<Address> addresses = new ArrayList<Address>();
        for (String key : configuration.getKeys(RABBITMQ_ADDR_PREFIX)) {
            if (key.endsWith(".host")) {
                String host = configuration.get(key, null);
                checkNotNull(host, "Configuration " + key + " is required");
                int port = configuration.getInt(key.replace(".host", ".port"), DEFAULT_PORT);
                addresses.add(new Address(host, port));
            }
        }
        return addresses.toArray(new Address[addresses.size()]);
    }
}