Redis 连接在 Vert.x 3.9.4 上丢失

Question

将vertx-redis-client升级到版本3.9.4后

需要更新连接代码以符合新版本。代码基于上述文档中的示例，如下所示：

Redis.createClient(vertx, redisOptions).connect(onConnect -> {
    if (onConnect.succeeded()) {
        RedisConnection client = onConnect.result();
        RedisAPI redis = RedisAPI.api(client);
        vertx.getOrCreateContext().put("redis", redis);
    }
});

但一个小时后（或多或少），我的连接丢失并出现以下错误堆栈跟踪：

io.vertx.redis.client.impl.ConnectionManager lambda$static[=12=] - Unhandled Error
java.nio.channels.ClosedChannelException 
at io.netty.channel.AbstractChannel$AbstractUnsafe.newClosedChannelException(AbstractChannel.java:957)
at io.netty.channel.AbstractChannel$AbstractUnsafe.write(AbstractChannel.java:865) 
at io.netty.channel.DefaultChannelPipeline$HeadContext.write(DefaultChannelPipeline.java:1367) 
at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:717) 
at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:764) 
at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:790) 
at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:758) 
at io.vertx.core.net.impl.ConnectionBase.write(ConnectionBase.java:124) 
at io.vertx.core.net.impl.ConnectionBase.writeToChannel(ConnectionBase.java:205) 
at io.vertx.core.net.impl.NetSocketImpl.writeMessage(NetSocketImpl.java:130) 
at io.vertx.core.net.impl.NetSocketImpl.write(NetSocketImpl.java:174) 
at io.vertx.core.net.impl.NetSocketImpl.write(NetSocketImpl.java:168) 
at io.vertx.redis.client.impl.RedisConnectionImpl.lambda$send(RedisConnectionImpl.java:136) 
at io.vertx.core.impl.ContextImpl.executeTask(ContextImpl.java:366) 
at io.vertx.core.impl.EventLoopContext.lambda$executeAsync[=12=](EventLoopContext.java:38) 
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164) 
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472) 
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:497) 
at io.netty.util.concurrent.SingleThreadEventExecutor.run(SingleThreadEventExecutor.java:989) 
at io.netty.util.internal.ThreadExecutorMap.run(ThreadExecutorMap.java:74) 
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) 
at java.lang.Thread.run(Thread.java:748)

有谁知道为什么会这样？或者知道如何解决这个问题？

Answer 1

如果您的连接长时间处于空闲状态，Redis 服务器可能会关闭连接。有几种方法可以解决这个问题。 issue

中解释了类似的内容

添加固定周期虚拟命令 (PING)，这样连接就不会关闭。

Redis.createClient(vertx, new RedisOptions()).connect(onConnect -> {
    if (onConnect.succeeded()) {
        RedisConnection client = onConnect.result();
        RedisAPI redis = RedisAPI.api(client);
        vertx.getOrCreateContext().put("redis", redis);

        vertx.setPeriodic(30 * 1000, handler -> {
            redis.ping(new ArrayList<>(), result -> {
                if (result.failed()) {
                    System.out.println("Error " + result.cause().getMessage());
                }
            });
        });
    }
});

添加将获取和替换您的连接的周期性任务。

final AtomicReference<RedisConnection> vertxConnection = new AtomicReference<>();
private void refreshConnection(Redis client, RedisConnection fallback) {
    // get a connection
    client.connect()
      .onFailure(err -> {
        // maybe log, don't change the current connection
        System.out.println("connect failed: " + err.getMessage());
        vertx.setTimer(5000L, t -> refreshConnection(client, fallback));
      })
      .onSuccess(conn -> {
        // swap old with new
        System.out.println("connect swapped: " + (conn != null ? conn.hashCode() : null));
        final RedisConnection old = vertxConnection.getAndSet(conn);
        vertx.setTimer(5000L, t -> refreshConnection(client, old));
        // the fallback isn't needed anymore
        if (fallback != null) {
          fallback.close();
        }
      });
  }
// create client
Redis client = Redis.createClient(vertx, redisOptions);

// get a connection
refreshConnection(client, null);

发生这种情况时添加异常处理程序以刷新连接，可以在官方文档中找到很好的例子：https://vertx.io/docs/vertx-redis-client/java/#_implementing_reconnect_on_error

Redis 连接在 Vert.x 3.9.4 上丢失

Redis connection lost on Vert.x 3.9.4

java

redis

vert.x