LPv2: Batch message logic (r2)

[lemunozm]

Description

This PR overrides the previous https://github.com/centrifuge/centrifuge-chain/pull/1923, in a simplified version

Responsibilities

• pallet-liquidity-pools-gateway knows to batch/unbatch but doesn't know what a Batch message is. To handle this, the LPMessage trait allows pack/unpack methods.
• pallet-liquidity-pools will never send or receive a batch. The gateway is responsible for the batching process.

Details

Batching is handled by two extrinsic:

• Gateway::start_batch_message(sender, destination): When calling this, any submitted messages from LP, that match the sender & destination will be packed. NOTE: We need to index also by destination domain because the destination information is not inside the message. So, we can never bundle two messages with two different destinations.
• Gateway::end_batch_message(sender, destination): When calling this, the batch is finally submitted. If this is not called, no message is sent. If the batch reaches the limit size, it will dispatch an error.

Later, the user can call pallet_utility::batch(calls), and any message sent between start_pack and end_pack will be bundled in the batch.

Changes

• Added Gateway::start_batch_message() and Gateway::end_batch_message() to allow creating batches.
• Renamed process_msg() to receive_message().
• Removed try_range for header message deserialization and use a BufferReader.
• Test message moved to the gateway mock.

Docs

See the updated diagrams: https://centrifuge.hackmd.io/i_wfI19XTgSkfWeN7IxXiQ?view

[lemunozm]

Still missings UTs, will do later, but the PR is ready to be reviewed

[lemunozm]

There are still pending batching tests (UTs and ITs). But maybe we can start merging this to avoid more conflicts with the incoming Cosmin PRs, WDYT?

We can fix some clean-ups in a next PR along with the tests.

cc @wischli @cdamian

[cdamian]

There are still pending batching tests (UTs and ITs). But maybe we can start merging this to avoid more conflicts with the incoming Cosmin PRs, WDYT?

We can fix some clean-ups in a next PR along with the tests.

cc @wischli @cdamian

I'm OK with this. If we merge this, I will rebase my multi-router branch, then you can continue with the rest of the stuff here.

[lemunozm]

@cdamian you will have quite conflicts but wanted to merge this ASAP to avoid even more 😅

Tell me if I can help you in the rebase 🙏🏻, or with some tricky union of some part

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 57.30337% with 38 lines in your changes missing coverage. Please review.

Project coverage is 47.69%. Comparing base (8245ce2) to head (7a9868d).

Files	Patch %	Lines
pallets/liquidity-pools-gateway/src/lib.rs	64.61%	23 Missing :warning:
pallets/liquidity-pools/src/message.rs	0.00%	12 Missing :warning:
libs/utils/src/lib.rs	90.00%	1 Missing :warning:
...pools-gateway/axelar-gateway-precompile/src/lib.rs	0.00%	1 Missing :warning:
pallets/liquidity-pools/src/lib.rs	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1949 +/- ## ========================================== - Coverage 47.72% 47.69% -0.04% ========================================== Files 184 183 -1 Lines 12969 12953 -16 ========================================== - Hits 6190 6178 -12 + Misses 6779 6775 -4 ```

:umbrella: View full report in Codecov by Sentry.
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[lemunozm]

@wischli @cdamian can we merge this to avoid conflicts with the cosmin part? 🙏🏻😃

[wischli]

@lemunozm Feel free to press the button. We can merge #1946 afterwards.