HeroicStartupPinger.java

/*
 * Copyright (c) 2015 Spotify AB.
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package com.spotify.heroic;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.collect.ImmutableList;
import com.spotify.heroic.cluster.ClusterManager;
import com.spotify.heroic.http.HttpServer;
import com.spotify.heroic.lifecycle.LifeCycleRegistry;
import com.spotify.heroic.lifecycle.LifeCycles;
import eu.toolchain.async.AsyncFramework;
import eu.toolchain.async.AsyncFuture;
import lombok.Data;
import lombok.ToString;
import lombok.extern.slf4j.Slf4j;

import javax.inject.Inject;
import javax.inject.Named;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.URI;
import java.util.Collection;
import java.util.List;
import java.util.Optional;

/**
 * Component that executes a startup 'ping' after the service has started.
 * <p>
 * This is used primarally to hook into integration tests to assert that the service has been
 * configured before tests are being executed.
 *
 * @author udoprog
 */
@Slf4j
@ToString(of = {"ping", "id"})
public class HeroicStartupPinger implements LifeCycles {
    private final Optional<HttpServer> server;
    private final ObjectMapper mapper;
    private final HeroicContext context;
    private final AsyncFramework async;
    private final ClusterManager cluster;
    private final URI ping;
    private final String id;

    @Inject
    public HeroicStartupPinger(
        final Optional<HttpServer> server, @Named("application/json") final ObjectMapper mapper,
        final HeroicContext context, final AsyncFramework async, final ClusterManager cluster,
        @Named("pingURI") final URI ping, @Named("pingId") final String id
    ) {
        this.server = server;
        this.mapper = mapper;
        this.context = context;
        this.async = async;
        this.cluster = cluster;
        this.ping = ping;
        this.id = id;
    }

    @Override
    public void register(LifeCycleRegistry registry) {
        registry.start(this::start);
    }

    private AsyncFuture<Void> start() {
        final AsyncFuture<Collection<String>> protocolFutures = async.collect(ImmutableList.copyOf(
            cluster.protocols().stream().map(p -> p.getListenURI()).iterator()));

        return protocolFutures.directTransform(uris -> {
            final ImmutableList<String> protocols = ImmutableList.copyOf(uris);

            context.startedFuture().onResolved(n -> {
                log.info("Sending startup ping to {}", ping);
                sendStartupPing(
                    new PingMessage(server.map(HttpServer::getPort).orElse(0), id, protocols));
            });

            return null;
        });
    }

    private void sendStartupPing(PingMessage p) throws IOException {
        switch (ping.getScheme()) {
            case "udp":
                sendUDP(p);
                break;
            default:
                throw new IllegalArgumentException("Startup URL scheme: " + ping.getScheme());
        }
    }

    private void sendUDP(PingMessage p) throws IOException {
        if (ping.getPort() == -1) {
            throw new IllegalArgumentException("Invalid URI, port is required: " + ping);
        }

        final byte[] frame = mapper.writeValueAsBytes(p);

        InetSocketAddress address = new InetSocketAddress(ping.getHost(), ping.getPort());
        final DatagramPacket packet = new DatagramPacket(frame, frame.length, address);

        try (final DatagramSocket socket = new DatagramSocket()) {
            socket.send(packet);
        }
    }

    @Data
    public static final class PingMessage {
        private final int port;
        private final String id;
        private final List<String> protocols;
    }
}