聊聊AsyncHttpClient的ClientStats

序

本文主要研究一下AsyncHttpClient的ClientStats

ClientStats

org/asynchttpclient/ClientStats.java

/**
 * A record class representing the state of an (@link org.asynchttpclient.AsyncHttpClient).
 */
public class ClientStats {

  private final Map statsPerHost;

  public ClientStats(Map statsPerHost) {
    this.statsPerHost = Collections.unmodifiableMap(statsPerHost);
  }

  /**
   * @return A map from hostname to statistics on that host's connections.
   * The returned map is unmodifiable.
   */
  public Map getStatsPerHost() {
    return statsPerHost;
  }

  /**
   * @return The sum of {@link #getTotalActiveConnectionCount()} and {@link #getTotalIdleConnectionCount()},
   * a long representing the total number of connections in the connection pool.
   */
  public long getTotalConnectionCount() {
    return statsPerHost
            .values()
            .stream()
            .mapToLong(HostStats::getHostConnectionCount)
            .sum();
  }

  /**
   * @return A long representing the number of active connections in the connection pool.
   */
  public long getTotalActiveConnectionCount() {
    return statsPerHost
            .values()
            .stream()
            .mapToLong(HostStats::getHostActiveConnectionCount)
            .sum();
  }

  /**
   * @return A long representing the number of idle connections in the connection pool.
   */
  public long getTotalIdleConnectionCount() {
    return statsPerHost
            .values()
            .stream()
            .mapToLong(HostStats::getHostIdleConnectionCount)
            .sum();
  }

  @Override
  public String toString() {
    return "There are " + getTotalConnectionCount() +
            " total connections, " + getTotalActiveConnectionCount() +
            " are active and " + getTotalIdleConnectionCount() + " are idle.";
  }

  @Override
  public boolean equals(final Object o) {
    if (this == o) return true;
    if (o == null || getClass() != o.getClass()) return false;
    final ClientStats that = (ClientStats) o;
    return Objects.equals(statsPerHost, that.statsPerHost);
  }

  @Override
  public int hashCode() {
    return Objects.hashCode(statsPerHost);
  }
}

ClientStats通过Map维护了每个host对应的统计；它提供了getStatsPerHost、getTotalConnectionCount、getTotalActiveConnectionCount、getTotalIdleConnectionCount方法

HostStats

org/asynchttpclient/HostStats.java

/**
 * A record class representing the status of connections to some host.
 */
public class HostStats {

  private final long activeConnectionCount;
  private final long idleConnectionCount;

  public HostStats(long activeConnectionCount,
                   long idleConnectionCount) {
    this.activeConnectionCount = activeConnectionCount;
    this.idleConnectionCount = idleConnectionCount;
  }

  /**
   * @return The sum of {@link #getHostActiveConnectionCount()} and {@link #getHostIdleConnectionCount()},
   * a long representing the total number of connections to this host.
   */
  public long getHostConnectionCount() {
    return activeConnectionCount + idleConnectionCount;
  }

  /**
   * @return A long representing the number of active connections to the host.
   */
  public long getHostActiveConnectionCount() {
    return activeConnectionCount;
  }

  /**
   * @return A long representing the number of idle connections in the connection pool.
   */
  public long getHostIdleConnectionCount() {
    return idleConnectionCount;
  }

  @Override
  public String toString() {
    return "There are " + getHostConnectionCount() +
            " total connections, " + getHostActiveConnectionCount() +
            " are active and " + getHostIdleConnectionCount() + " are idle.";
  }

  @Override
  public boolean equals(final Object o) {
    if (this == o) return true;
    if (o == null || getClass() != o.getClass()) return false;
    final HostStats hostStats = (HostStats) o;
    return activeConnectionCount == hostStats.activeConnectionCount &&
            idleConnectionCount == hostStats.idleConnectionCount;
  }

  @Override
  public int hashCode() {
    return Objects.hash(activeConnectionCount, idleConnectionCount);
  }
}

HostStats定义了activeConnectionCount、idleConnectionCount属性

getClientStats

org/asynchttpclient/netty/channel/ChannelManager.java

  public ClientStats getClientStats() {
    Map totalConnectionsPerHost = openChannels.stream().map(Channel::remoteAddress).filter(a -> a.getClass() == InetSocketAddress.class)
            .map(a -> (InetSocketAddress) a).map(InetSocketAddress::getHostName).collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));
    Map idleConnectionsPerHost = channelPool.getIdleChannelCountPerHost();
    Map statsPerHost = totalConnectionsPerHost.entrySet().stream().collect(Collectors.toMap(Entry::getKey, entry -> {
      final long totalConnectionCount = entry.getValue();
      final long idleConnectionCount = idleConnectionsPerHost.getOrDefault(entry.getKey(), 0L);
      final long activeConnectionCount = totalConnectionCount - idleConnectionCount;
      return new HostStats(activeConnectionCount, idleConnectionCount);
    }));
    return new ClientStats(statsPerHost);
  }

ChannelManager提供了getClientStats方法，它从openChannels获取totalConnectionsPerHost，从channelPool.getIdleChannelCountPerHost()获取idleConnectionCount，然后创建HostStats，最后返回ClientStats

小结

AsyncHttpClient提供了ClientStats用于获取连接的统计信息，可按host维度，统计activeConnectionCount、idleConnectionCount，也可汇总查看totalConnectionCount、totalActiveConnectionCount、totalIdleConnectionCount。它可以从ChannelManager获取。对于使用micrometer的可以使用这个作为数据源进行适配。