Source Directory Update message processing by EMA Consumer application

kelvinyoung048
kelvinyoung048 Explorer
in Elektron

We are writing a consumer application to connect to TREP:

  1. When
    a Source Directory Update message is received indicating AcceptingRequests=No, what should be done by the application when it needs to create a new
    item stream? (Should the application search for another service that provides
    the same Capabilities and use that service to send new item requests?)
  2. When a Source Directory Update message is received
    indicating Status = None, according to EMA30_RDMUsageGuideAPI fan out it to Status message for each item
    stream? Suppose we are using a service related to MarketPrice domain. Then does this mean, the application receives MarketPrice Status messages for each item stream that have been opened. If so, what
    will be the DataState and StreamState of each Status message received by the application?
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Best Answer

  • moragodkrit.chumsri_1
    moragodkrit.chumsri_1 LSEG
    Answer ✓

    @kelvinyoung048

    For #1

    I think your understanding is correct.
    From section 4.4.2 ServiceState and AcceptingRequests
    If the servicestate is up but acceptingRequests is No. The immediate provider is not accepting new
    requests. However reissue requests on already open streams can be processed. In this case you want to send a
    new item requests(not reissue), so you need to find another service that provide the capability you want to request and the new service must have ServiceState=Up and AcceptingRequests=Yes.

    For #2

    As far as I understand,for the publisher/provider such as UPA/ETA provider, sending Status with directory is
    equivalent to sending an RsslStatusMsg to each item. This status only applies to item streams that have received a refresh or status of stream state OPEN with data state OK(OPEN/OK). I think None in the Status is the status code inside Status object. Therefore EMA Consumer should receive stream state Open and Data state OK.

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