EMA channel failover and tunnel stream

ye.li
ye.li
in EMA

I am using EMA C++ application and create a tunnel stream for posting messages.

I have two channels in the Ema Config. When channel 1 has status of down, it works as expected to auto failover to channel 2.

Question:

if a tunnel stream is already created after channel 1 is up, when channel 1 is down and failover to channel 2, is the original tunnel stream still valid? Or do I have to create a new tunnel stream for posting data.


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Best Answer

  • veerapath.rungruengrayubkul
    veerapath.rungruengrayubkul
    Answer ✓

    To close the tunnel stream, the unregister method can be called on the tunnel stream handle. The call has been implemented and there have been no issue since June 10th.

Answers

  • veerapath.rungruengrayubkul
    veerapath.rungruengrayubkul

    Hi @ye.li,

    Once connection is down, the Tunnel Stream will be closed and there is no recovery on tunnel stream. Application has to create a new Tunnel Stream once the connection is recovered or failover. You can find the instructions for EMA application to handle the tunnel stream recovery in this question. The instructions are similar for both EMA C++ and Java.

  • ye.li
    ye.li

    okay, I can create a new tunnel stream in the onUpdateMsg for directory domain. However sometimes i got the following errors in the log after i log on to the private tunnel stream. What do these errors mean? I haven't posted anything yet when I received them.

    loggerMsg
    TimeStamp: 2020/06/04 17:17:25.729
    ClientName: TunnelItem
    Severity: Error
    Text: Internal error. Current stream Id in TunnelItem::getSubItem( UInt32 ) is less than the starting stream id.
    loggerMsgEnd

    loggerMsg
    TimeStamp: 2020/06/04 17:17:25.729
    ClientName: ItemCallbackClient
    Severity: Error
    Text: Received a tunnel stream message event containing sub stream message with unknown streamId 1. Message is dropped.
    Instance Name TRConsumer_1
    RsslChannel 0x0x1759550
    Tunnel Stream Handle 140323426698640
    Tunnel Stream name XXX_TUNNEL
    Tunnel Stream serviceId 10
    Tunnel Stream streamId 6
    loggerMsgEnd




  • veerapath.rungruengrayubkul
    veerapath.rungruengrayubkul

    Hi @ye.li,

    From the code, the error message indicates that EMA received a tunnel stream message containing sub stream message with invalid stream ID (1).

    To investigate the issue:

    - please enable and provide me the message tracing. The tracing should log the raw message received from network.

    To enable the tracing, please add the XmlTraceToFile parameter for the Channel that you wish to enable Xml Trace for. The file will be in "emaLog_<pid>.log" format.

    e.g.

    <Channel>
    <Name value="Channel_1"/>
    <ChannelType value="ChannelType::RSSL_SOCKET"/>
    ...
    <XmlTraceToFile value="1"/> 
    </Channel>

    - provide snippet code of your modification which recreates the tunnel stream.

  • ye.li
    ye.li

    The issue doesn't happen all the time, and didn't reproduce it until yesterday. I got the same error, it happened after a normal tunnel stream open and login.

    attached logger file logger_error.txt

    ema trace file EmaTrace_error.txt


  • veerapath.rungruengrayubkul
    veerapath.rungruengrayubkul

    Hi @ye.li,

    Thanks for the files. I have seen the following message received from server. The Status message was sent on tunnel stream with stream id=1 which is not valid stream id for EMA so the error message was logged.

    To investigate this issue further, please contact Contribution Channel support to verify the cause of the "Duplicate Session Name Detected - Please contact support - Your connection will now be closed. Issued by CFE" status. On the MyRefinitiv Product support, please select the "Thomson Reuters Contributions Channel" as Product. 

    <!-- End Message (Channel IPC descriptor = 16) -->
    <!-- Incoming Message (Channel IPC descriptor = 16) -->
    <!-- Time: 10:41:25:310 -->
    <!-- rwfMajorVer="14" rwfMinorVer="1" -->
    <genericMsg domainType="RSSL_DMT_SYSTEM" streamId="4" containerType="RSSL_DT_MSG" flags="0x19 (RSSL_GNMF_HAS_EXTENDED_HEADER|RSSL_GNMF_HAS_SEQ_NUM|RSSL_GNMF_MESSAGE_COMPLETE)" seqNum="6" dataSize="121">
        <extendedHeader data="0100"/>
        <dataBody>
    <!-- rwfMajorVer="14" rwfMinorVer="1" -->
            <statusMsg domainType="RSSL_DMT_MARKET_PRICE" streamId="1" containerType="RSSL_DT_NO_DATA" flags="0x60 (RSSL_STMF_HAS_STATE|RSSL_STMF_CLEAR_CACHE)" dataState="RSSL_DATA_SUSPECT" streamState="RSSL_STREAM_CLOSED" code="RSSL_SC_NOT_ENTITLED" text="Duplicate Session Name Detected - Please contact support - Your connection will now be closed. Issued by CFE"  dataSize="0">
                <dataBody>
                </dataBody>
            </statusMsg>
        </dataBody>
    </genericMsg>
  • ye.li
    ye.li

    I reached out to the product support on the duplicate session error. They said it could be related to previous session is not properly closed.

    When I exit the application, do I need to close the post stream or the tunnel stream or unregister anything?


  • veerapath.rungruengrayubkul
    veerapath.rungruengrayubkul
    Hi @ye.li,

    I have been looking into the cleanup method. I will keep you posted.

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