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rinki.goyal avatar image
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How to specify multiple hosts while connecting using ETA reactor api?

I am using reactor api for consuming data from reuters feed. How to specify multiple hosts in connection config?

I am using below code:

connectOptions.connectionList().add(connectInfo);
   connectOptions.connectionList().get(0).connectOptions().majorVersion(Codec.majorVersion());
   connectOptions.connectionList().get(0).connectOptions().minorVersion(Codec.minorVersion());
   connectOptions.connectionList().get(0).connectOptions().connectionType(ConnectionTypes.SOCKET);
   connectOptions.connectionList().get(0).connectOptions().unifiedNetworkInfo().address(srvrHostname);
   connectOptions.connectionList().get(0).connectOptions().unifiedNetworkInfo().serviceName(srvrPortNo);
   connectOptions.connectionList().get(0).connectOptions().guaranteedOutputBuffers(1000);


   // Prepare our connection
//connectOptions.connectionList().add(connectInfo);
   connectOptions.connectionList().get(1).connectOptions().majorVersion(Codec.majorVersion());
   connectOptions.connectionList().get(1).connectOptions().minorVersion(Codec.minorVersion());
   connectOptions.connectionList().get(1).connectOptions().connectionType(ConnectionTypes.SOCKET);
   connectOptions.connectionList().get(1).connectOptions().unifiedNetworkInfo().address(srvrHostname2);
   connectOptions.connectionList().get(1).connectOptions().unifiedNetworkInfo().serviceName(srvrPortNo);
   connectOptions.connectionList().get(1).connectOptions().guaranteedOutputBuffers(1000);

After hit trial, I noticed that by uncommenting the code, I can make connection.

However, when I print host name in channel_Up or channel_ready events, It is always 2nd host i.e. 

connectOptions.connectionList().get(1).connectOptions().unifiedNetworkInfo().address(srvrHostname2);


1) Is above correct way to connect using multiple hosts ?

2) I am using reconnect tries as -1, so how reactor api will be failed over to other host in pipeline?

eta-apireactor
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Shadab Hussain avatar image   Shadab Hussain

Hi @rinki.goyal,

Thank you for your participation in the forum. Is the reply below satisfactory in resolving your query?

If so please can you click the 'Accept' text next to the appropriate reply? This will guide all community members who have a similar question.


Thanks,

AHS

Shadab Hussain avatar image   Shadab Hussain

Hi @rinki.goyal,

Please be informed that a reply has been verified as correct in answering the question, and has been marked as such.


Thanks,

AHS

3 Answers

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Jirapongse avatar image
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@rinki.goyal

You can refer to the VAConsumer example code. It demonstrates how to add a backup server.

        if (consumerCmdLineParser.backupHostname() != null && consumerCmdLineParser.backupPort() != null)
        {
            ReactorConnectInfo connectInfo = ReactorFactory.createReactorConnectInfo();
            chnlInfo.connectOptions.connectionList().add(connectInfo);
            chnlInfo.connectOptions.connectionList().get(1).connectOptions().majorVersion(Codec.majorVersion());
            chnlInfo.connectOptions.connectionList().get(1).connectOptions().minorVersion(Codec.minorVersion());
            chnlInfo.connectOptions.connectionList().get(1).connectOptions().connectionType(chnlInfo.connectionArg.connectionType());
            chnlInfo.connectOptions.connectionList().get(1).connectOptions().unifiedNetworkInfo().serviceName(consumerCmdLineParser.backupPort());
            chnlInfo.connectOptions.connectionList().get(1).connectOptions().unifiedNetworkInfo().address(consumerCmdLineParser.backupHostname());
            chnlInfo.connectOptions.connectionList().get(1).connectOptions().userSpecObject(chnlInfo);
            chnlInfo.connectOptions.connectionList().get(1).connectOptions().guaranteedOutputBuffers(1000);

It creates a new instance of ReactorConnectInfo and then adds it to the connection list.

Please let me know which line causes the index out-of-bounds exception.

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rinki.goyal avatar image rinki.goyal
@Jirapongse please see below comment
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rinki.goyal avatar image
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@Jirapongse

If i uncomment this line , then i wont get Index out of bound exception

  1. //connectOptions.connectionList().add(connectInfo);

IF there are two hosts, then we need below line twice :

connectOptions.connectionList().add(connectInfo);


I have fixed the code to below, however I still dont see in logs connection being made to back up host, Could you please assist here ?

private ReactorConnectInfo backUpConnectInfo = ReactorFactory.createReactorConnectInfo();
private ReactorDispatchOptions dispatchOptions = ReactorFactory.createReactorDispatchOptions();
// Prepare our connection
    connectOptions.connectionList().add(connectInfo);
        connectOptions.connectionList().get(0).connectOptions().majorVersion(Codec.majorVersion());
        connectOptions.connectionList().get(0).connectOptions().minorVersion(Codec.minorVersion());
        connectOptions.connectionList().get(0).connectOptions().connectionType(ConnectionTypes.SOCKET);
        connectOptions.connectionList().get(0).connectOptions().unifiedNetworkInfo().address(srvrHostname);
        connectOptions.connectionList().get(0).connectOptions().unifiedNetworkInfo().serviceName(srvrPortNo);
        connectOptions.connectionList().get(0).connectOptions().guaranteedOutputBuffers(1000);


        // Prepare our back up connection
connectOptions.connectionList().add(backUpConnectInfo);
connectOptions.connectionList().get(1).connectOptions().majorVersion(Codec.majorVersion());
        connectOptions.connectionList().get(1).connectOptions().minorVersion(Codec.minorVersion());
        connectOptions.connectionList().get(1).connectOptions().connectionType(ConnectionTypes.SOCKET);
        connectOptions.connectionList().get(1).connectOptions().unifiedNetworkInfo().address(srvrHostname2);
        connectOptions.connectionList().get(1).connectOptions().unifiedNetworkInfo().serviceName(srvrPortNo);
        connectOptions.connectionList().get(1).connectOptions().guaranteedOutputBuffers(1000);



        connectOptions.reconnectAttemptLimit(-1); // attempt to recover forever
        connectOptions.reconnectMinDelay(1000); // 1 second minimum
        connectOptions.reconnectMaxDelay(60000); // 60 second
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Jirapongse avatar image
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@rinki.goyal

You can specify many ReactorConnectInfo in the connection list but ETA will connect to one server at a time. For example, if you have two servers in the list, ETA will establish a connection to the first server. It will failover to the second server if it can detect disconnection from the first server.


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