Exchange Stream API Release - 19th Nov 2019 - SUB_IMAGE change

[BetfairDeveloperProgram]

We are contacting you to regarding an Exchange Stream API release scheduled to take place on Tuesday 19th Nov.

Please be aware that, following this release, it will be possible for a Change Message with ChangeType ('ct') SUB_IMAGE to be published while a subscription is on-going.

This message should be interpreted in the same way as the initial image returned at the start of subscription: it contains the current state of all markets matching the existing subscription and should replace any existing values in any local cache.

This may cause a slight pause in message delivery but should be an infrequent event with gaps of weeks to months between occurrences. This will only occur if for some reason the set of markets available to you has changed e.g. due to technical maintenance or licensing changes.

To allow customers to test the above SUB_IMAGE change, we’ll simulate this behaviour on the following dates on the Exchange Stream API integration endpoint - stream-api-integration.betfair.com

Monday - 11th Nov - 10:00 GMT
Tuesday - 12th Nov - 10:00 GMT
Wednesday - 13th Nov - 10:00 GMT
Thursday - 14th Nov - 10:00 GMT
Friday - 15th Nov - 10:00 GMT

At this time, all connections to the stream-api-integration.betfair.com endpoint with receive a Change Message with ChangeType ('ct') SUB_IMAGE


Betfair Developer Program

[LiamP]

Is it possible to get an example of this through the integration endpoint before release?

[BetfairDeveloperProgram]

Hi LiamP

Yes, we'll add this capability and will let you know as soon as this is available.

Kind Regards

Neil

[BetfairDeveloperProgram]

Hi LiamP.

i've now added details of when and how this can be tested in the announcement above.

Thanks

Neil

[geoffw123]

Hi Neil

Presumbably this change means a code change is required in your Streaming example code ? If so can you confirm if and when you will be updating the github client example code ?

Thanks

Geoff

[LetsGo]

Hi Neil,

What are the consequence of not making this change to my code?
For example, will I be unsubscribed to the market or just lose a streaming market change?

Thanks

[LiamP]

Anyone have a connection that got data? Mine failed...

betfairlightweight.exceptions.ListenerError: 
connection_id: 100-061119095447-34, 
data: {"op":"status","statusCode":"FAILURE","errorCode":"UNEXPECTED_ERROR","errorMessage":"Unable to provide initial image due to capacity limitations, please try again","connectionClosed":true,"connectionId":"100-0611134395937-3434"}

[bfexplorer]

Do you really simulate this new behaviour because I just switched to stream-api-integration.betfair.com, and I did not notice SUB_IMAGE.

I have done test on my desktop app, and as well prepared simple code for testing, so the question is how we should write our unit test code for this new feature?

Well yes, all seems to be working as before for me.

Here is video from my test:

https://youtu.be/oNnA1NI_Xps

[WTPooh]

It looks like no changes are needed for the sample C# client.
Here is how it works now:
MarketCache.cs

public void OnMarketChange(ChangeMessage<MarketChange> changeMessage)
{
if (changeMessage.IsStartOfNewSubscription)
{
//clear cache
_markets.Clear();
}
//...
}

ChangeMessage.cs

public bool IsStartOfNewSubscription
{
get
{
return ChangeType == ChangeType.SUB_IMAGE &&
(SegmentType == SegmentType.NONE || SegmentType == SegmentType.SEG_START);
}
}

[BetfairDeveloperProgram]

Today's test on the stream-api-integration.betfair.com endpoint worked for some connections but the image executor got overloaded and had to disconnect the remaining ones.

We are preparing a fix for the next test which will now take place on Friday at 10:00 GMT.

Kind Regards

Neil

[LiamP]

Today's test on the stream-api-integration.betfair.com endpoint worked for some connections but the image executor got overloaded and had to disconnect the remaining ones.

We are preparing a fix for the next test which will now take place on Friday at 10:00 GMT.

Kind Regards

Neil

Hi Neil,

I am not going to be available on Friday, is it possible to add a test next week as well? Seem to be cutting it very fine with it being released on Tuesday, will this be pushed back due to today’s problems?

[BetfairDeveloperProgram]

Morning Liam.

Yes, can add an additional test period on on Monday moring at 10am. I'll update the schedule accordingly.

I'll know whether or not the release on Tuesday will go ahead as planned before the of the day and will provide an update regarding this then,

Kind Regards

Neil

[BetfairDeveloperProgram]

The above release has now been delayed until the 19th November and new testing times have been added from Monday - Friday next week.

Kind Regards

Neil

[LetsGo]

Good sense and sound judgement in practical matters as always from the BDP team.

[LiamP]

Excellent, thanks Neil.