Class IdleConnectionReaper

  • All Implemented Interfaces:
    Runnable

    public final class IdleConnectionReaper
    extends Thread
    Daemon thread to periodically check connection pools for idle connections.

    Connections sitting around idle in the HTTP connection pool for too long will eventually be terminated by the AWS end of the connection, and will go into CLOSE_WAIT. If this happens, sockets will sit around in CLOSE_WAIT, still using resources on the client side to manage that socket. Many sockets stuck in CLOSE_WAIT can prevent the OS from creating new connections.

    This class closes idle connections before they can move into the CLOSE_WAIT state.

    This thread is important because by default, we disable Apache HttpClient's stale connection checking, so without this thread running in the background, cleaning up old/inactive HTTP connections, we'd see more IO exceptions when stale connections (i.e. closed on the AWS side) are left in the connection pool, and requests grab one of them to begin executing a request.

    • Method Detail

      • registerConnectionManager

        public static boolean registerConnectionManager​(org.apache.http.conn.HttpClientConnectionManager connectionManager)
        Registers the given connection manager with this reaper;
        Returns:
        true if the connection manager has been successfully registered; false otherwise.
      • removeConnectionManager

        public static boolean removeConnectionManager​(org.apache.http.conn.HttpClientConnectionManager connectionManager)
        Removes the given connection manager from this reaper, and shutting down the reaper if there is zero connection manager left.
        Returns:
        true if the connection manager has been successfully removed; false otherwise.
      • shutdown

        public static boolean shutdown()
        Shuts down the thread, allowing the class and instance to be collected.

        Since this is a daemon thread, its running will not prevent JVM shutdown. It will, however, prevent this class from being unloaded or garbage collected, in the context of a long-running application, until it is interrupted. This method will stop the thread's execution and clear its state. Any use of a service client will cause the thread to be restarted.

        Returns:
        true if an actual shutdown has been made; false otherwise.
      • run

        public void run()
        Specified by:
        run in interface Runnable
        Overrides:
        run in class Thread