Azure Topic Subscription Names Limited to 50 Characters

[SimonCropp]

Raised by @onesadjam
Migrated from by Particular/NServiceBus#1300

When using Azure Service Bus to manage PubSub, the name of the subscription to a topic is limited to 50 characters. The naming convention for topic subscriptions is [endpoint queue name].[message type]. We have rather descriptive queue and message names, and ran into this limitation. The endpoint continued to run even though the subscription could not be made.

Recommendations:

• Fail fast if the topic subscription cannot be made
• Lobby Microsoft to increase the string length of topic subscription names :-)

[SimonCropp]

Raised by @johnsimons

@onesadjam Feel like sending us a PR to fix this?

[SimonCropp]

Raised by @SimonCropp

@onesadjam

"Lobby Microsoft to increase the string length of topic subscription names " that is a great idea. please attach the MS connect issue url and I will vote for it

"Fail fast if the topic subscription cannot be made" fail fast is problematic. we have discovered this the hard way Particular/NServiceBus#1137 As @johnsimons suggested could you put together a PR that illustrates how you would handle this

[SimonCropp]

Raised by @onesadjam

I submitted an idea on Connect, feel free to pile on: http://visualstudio.uservoice.com/forums/121579-visual-studio/suggestions/4175354-increase-the-maximum-length-of-the-name-of-a-topic

I've not performed a pull-request to this project, or any project on github for that matter. Do you have guidelines that I should reference to get started?

[SimonCropp]

Raised by @SimonCropp

@onesadjam here you go https://github.com/NServiceBus/NServiceBus/blob/develop/CONTRIBUTING.md

[SimonCropp]

Raised by @SimonCropp

Particular/NServiceBus#1341

[SimonCropp]

Raised by @SimonCropp

@onesadjam how did you go?

[SimonCropp]

Raised by @onesadjam

I don't think I'm going to be able to supply a PR. We are currently
working around this issue by using names that do not result in overflowing
the subscription name length limit. The issue posted to MS connect
received 4 votes and a comment from an MS rep that they are reviewing it
for future release.

[SimonCropp]

Raised by @andreasohlund

Both websphere and windows service bus is solving this by generating
shorter q names using deterministic guids

https://github.com/Particular/NServiceBus.WebSphereMQ/blob/master/src/NServiceBus.Transports.WebSphereMQ/WebSphereMqAddress.cs#L47

Would that work here?

[SimonCropp]

Raised by @onesadjam

That looks like it would work, but it would make upgrading from the current
NSB to the new pattern painful. The steps would be:

• Delete existing subscription (and start missing events due to this)
• Restart endpoint to force the subscription to be recreated
• Modify the filter rule for the subscription (the filter rule created in
  the previous step enforces that the subscriber will only receive messages
  when the publisher is referencing the same build of the message definition
  assembly as the subscriber).

[SimonCropp]

Raised by @andreasohlund

Since we only do this for names > 50 there is no backwards compatibility issue?

[SimonCropp]

Raised by @onesadjam

True, if the implementation is to only apply the hash when the name exceeds
the limit it would eliminate the backwards compatibility issue.

[aanttila]

Since the original User Voice for increasing the length of queue names was closed because it was submitted to the wrong team, I've created a new request here:
https://feedback.azure.com/forums/216926-service-bus/suggestions/18552391-increase-the-maximum-length-of-the-name-of-a-topic

[SeanFeldman]

@aanttila thank you. You might to want straight to the ASB dev team and raise it in https://github.com/Azure/azure-service-bus