How should I respond to A7 Source did not respond

james_molohon
james_molohon Explorer
in WebSocket API

My application submits a batch streaming request with many rics. Some rics received the status response A7 Source did not respond.
What is the appropriate way to handle this? Will the Elektron Websocket API resume sending updates when they are available without any intervention, or is it like a poison message, and once I have received this I will not receive any updates?


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Best Answer

  • wasin.w
    wasin.w admin
    Answer ✓

    Hi @james_molohon

    The "A7: Source did not respond" is generated by the ADS server. This status message sent when a requested service is known to be available but ADS did not receive a response for an item and the item retry limit has been reached.

    Therefore, this would indicate that the ADH is not sending the instrument to the ADS / it is not receiving the item from the ADH for some reason.

    I recommend you contact Elektron Realtime support team to help you investigate this issue in more detail.


Answers

  • james_molohon
    james_molohon Explorer

    Thank you for your response @Wasin Waeosri We've already been in contact with the support team, and learned there was a system outage that I could monitor status by subscribing to ric "ALERT55".

    My question is about the future, when this status is sent, and what steps are necessary on my end to recover. Will ADS stream any updates for a ric after that message is sent?

    I ask this because when I observed this A7 message in the application log, I was able to connect to the ADS from my browser and receive tick updates for the same ric.

  • wasin.w
    wasin.w admin

    Hello @james_molohon

    The application can check for the Status Response Message (message type "Status") attributes to verify the action on the consumer application side.

    • Data: Represents the quality of the data in the response or in the event stream.
    • Stream: The state of the event stream when using the request/response with interest paradigm.
    • Text: Specifies additional information about the current state.

    Example Status message is following:

    {
        "ID":2,
        "Key":{
          "Name":"IBM.N",
          "Service":"API_RDF"
        },
        "State":{
          "Data":"Suspect",
          "Stream":"Open",
          "Text":"A23: Service has gone down. Will recall when service becomes available."
        },
        "Type":"Status"
      }

    If the application gets "Stream": "Open" with "Data":"Suspect" values, it means the item stream remain opened but data is not available right now. Basically, TREP/Elektron automatic recovery item subscription for the application once the problem resolved on the server-side. However, if it takes too long you may need to contact the Elektron Support team.

    If the application gets "Stream":"Closed" value, it means the item stream is closed because the data is not available on this service.

    If the application gets "Stream":"ClosedRecover" value, it means the item stream is closed however data can be recovered on this service and connection at a later time.

    Please see more detail regarding other Stream/Data State values in the Status Message Document of Elektron WebSocket API Developer Guide page.

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