Add support for Google Cloud Pub/Sub as a transport

[CharlieDigital]

Hey there, I am interested in taking on the implementation of the Google Cloud Pub/Sub transport.

• There are currently no .NET messaging middleware that supports Pub/Sub
• Wolverine's support is actually a bit broken because it utilizes the wrong SDK/API and is subject to frequent disconnects
• Wolverine's design of bundled handlers is somewhat antithetical to how Pub/Sub works

The implementer of Wolverine's Pub/Sub used the emulator for testing which does not behave correctly (as the streaming pull API will consistently drop connections and is reliant on the higher level SDK to manage a pool of connections/reconnect).

There are some things I'm curious about before embarking.

Objective

Add support for Google Cloud Pub/Sub as a transport.

See also: #1821

Key Items

• Key design/contributor docs to read?
• What is the general high level architecture?
  • Would Azure Service Bus be the closest analogue to use as a template?
• I am seeking more clarity around the testing approach
• I am seeking some more clarity around the Reactor/Proactor pattern (ELI5 🤣)
  • I've done some reading, but it's not clear to me how it fits into Brighter's architecture
• Any known gotchas with Pub/Sub to be aware of as it pertains to Brighter's architecture?
  • FIFO config?
  • At most once support?
• As my primary goal is to have this implemented for use in a business context, what is the best approach to ensure that my team can publish builds at a faster pace than the Brighter team might want to ship?
• What can I expect around the pace of publishing releases?
• What is the best way to perform real-world testing as I'm developing?

Would love some feedback; really want to understand workflow/process.

[iancooper]

Hi Charlie, thanks for raising these. I'll provide a full reply in the next couple of days.

[iancooper]

Hi @CharlieDigital, it looks like @lillo42 has a backlog item for this one. Let's see if you had any feedback on that. If you want to tackle another transport or make improvements, we would still be delighted to find a way to get you involved.