Initial offline mode ADR

[cardenaso11]

Making this draft publicly visible before the full PR etc, so everyone can see what to prepare for ahead of time. The current status of the implementation, is that it is nearing completion.

This ADR is for support for an offline mode, for the hydra-node target. SundaeSwap intends to contribute these patches upstream. Feedback is welcome, if there are any questions or suggestions or problems.

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• CHANGELOG updated or not needed
• Documentation updated or not needed
• Haddocks updated or not needed
• No new TODOs introduced or explained hereafter

[abailly-iohk]

Some comments left, I think we could probably pair or work in team on this ADR to speed up the feedback loop

[cardenaso11]

Some comments left, I think we could probably pair or work in team on this ADR to speed up the feedback loop

Thank you! Taking a look now. Making some initial adjustments based on feedback, will message about pairing. Sounds good to me

[abailly-iohk]

Following our discussion, an updated lightweight architecture diagram taking into account what would be dropped/adapted:

[abailly-iohk]

@cardenaso11 Do you want more feedback on this? Is it ready for review, or do you want to make the ADR part of the PR introducing the feature?

[abailly-iohk]

Follow-up discussion outcome:

• Implement a "mock chain" by providing a Chain m tx handler and do not bother with mocking actual Cardano interactions
• "Dependency injection" Is not really needed in Direct but could improve readability and maintainability of hydra-cluster code
• Old mock-chain code from the early days of Hydra could be useful inspiration

  hydra/local-cluster/src/HydraNode.hs

  Line 207 in 00026ec

  withMockChain :: ((Int, Int, Int) -> IO ()) -> IO ()

• Polishing the off-line ADR
• Need more work to refine the need for the event streaming ADR

[abailly-iohk]

@cardenaso11 I would like to move this forward, I think the off-line ADR is in good shape and it's in Proposed state anyway, until the PR comes in. Can you remove the other one?

[cardenaso11]

@cardenaso11 I would like to move this forward, I think the off-line ADR is in good shape and it's in Proposed state anyway, until the PR comes in. Can you remove the other one?

Absolutely, thanks a ton. I'd done that locally but think I had not pushed it

[cardenaso11]

GitHub UI somehow rebased like 3 times instead of one for some reason, but either way, removed the other ADR. I also added the edits based on our meeting, let me know if anything else would help. Thanks a ton, @abailly-iohk

[abailly-iohk]

Some comments to clarify

[v0d1ch]

@cardenaso11 This looks good to me. Not sure if we want to specify exactly how to get to the open Head with this initial utxo we will have as the argument to hydra-node and bypass Commit. Perhaps this would be too much information for an adr and can be left for the implementation.

[abailly-iohk]

@cardenaso11 Apart from some minor comments, we are good to go :)

[cardenaso11]

Great! Let me know if there's anything else remaining on this ADR to get merged, in the meantime I am gonna make sure the actual cleaned up implementation branch is reviewable for you guys by Monday. Thanks a ton!

[abailly-iohk]

@cardenaso11 Seems like you need to add your handle to the authors.yml :)