Craft cardano-client library

[coot]

• export block, header, tx types from ouroboros-consensus
• export NodeToClient
• specialise all the codecs for the current version of consensus
• export common tx-submission client (which is common for wallet, explorer), and export null tx submission client for explorer
• prefix modules with Cardano.Client (?)

It should export everything that is required by cardano-explorer and cardano-wallet (in cardano-node), and hide the dependency on ouroboros-network and ouroboros-consensus.

[mrBliss]

@coot Is somebody working on this?

@erikd is this necessary for 1.0.0 or 1.1.0?

[coot]

@mrBliss not yet; I don't think this is necessary, but it's nice to have.

[erikd]

The time this was really needed was back in July when I started work on the explorer.

Do we need this now? Well that depends on how much the APIs in network (and to a lesser extent node) are going to change. Every time they do change I spend significant amounts of time chasing type errors trying to unbreak the explorer. Since network exposes so much of its internals, much of the code that needs fixing is due to type changes in code that should be in this proposed client library anyway. Ignoring all this extra stuff the interface between network and the explorer is actually really small.

[coot]

@erikd I am aware that it's still needed, we didn't had time to start working on it. There will be substantial changes in the future, though I am not sure we'll have time to finish cardano-client before they will land. The wallet team will also appreciate a simpler interface.

[edsko]

I am removing the consensus label from this ticket. Once the networking layer has a clear API, we can use that as a basis for an API for consensus (though consensus already provides a reasonably concise API through run).

[dcoutts]

This is very useful to simplify clients, but it is not release critical.

[coot]

This is subsumed by the cardano-cli library in cardano-node repository.