|| || || || || || || ||

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ChannelProxy.h

Go to the documentation of this file.

#ifndef Impala_Util_ChannelProxy_h
#define Impala_Util_ChannelProxy_h

#include "Util/ChannelPool.h"
#include "Util/Channel.h"

namespace Impala
{
namespace Util
{

/**********************************************************************
 Instances of this class support communication with channel based
 servers, hiding explicit channel management.
***********************************************************************/

class ChannelProxy
{

public:

    ChannelProxy(CString serverName, int port, CString passwordFile) :
        mServer(serverName), mPort(port), mPasswordFile(passwordFile),
        mChannel(0)
    {
    }

    virtual
    ~ChannelProxy()
    {
    }

    bool
    GetChannel()
    {
        ILOG_INFO("Need a channel to " << mServer << ":" << mPort);
        mChannel = ChannelPool::Instance().Get(mServer, mPort, mPasswordFile);
        if (ChannelIsValid())
        {
            ILOG_INFO("Open channel to " << mServer << " available at port " <<
                      mChannel->GetPortNumber(0));
            return true;
        }
        else
        {
            ILOG_ERROR("No valid channel to " << mServer << ":" << mPort);
            return false;
        }
    }

    bool
    ChannelIsValid()
    {
        return (mChannel && mChannel->Valid());
    }

    String
    Send(CString msg)
    {
        if (!ChannelIsValid())
        {
            ILOG_ERROR("Invalid channel, cannot send");
            return "ERROR";
        }

        ILOG_DEBUG("Sending: " << msg);

        char* buf = mChannel->Buffer();
        sprintf(buf, "%s\0", msg.c_str());
        int len = mChannel->SendRequest(strlen(buf) + 1);

        if (len < 0)
        {
            ILOG_ERROR("Send failed (" << len << "); closing channel");
            ChannelPool::Instance().Remove(mServer, mPort);
            mChannel = 0;
            return "ERROR: 503: Send failed; closing channel";
        }

        buf[len] = 0;
        ILOG_DEBUG("Response: " << buf);
        return String(buf);
    }

private:

    String   mServer;
    int      mPort;
    String   mPasswordFile;
    Channel* mChannel;

    ILOG_VAR_DECL;

}; // class

ILOG_VAR_INIT(ChannelProxy, Impala.Util);

} // namespace 
} // namespace 

#endif

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