Support for bidirectional routers

[lemunozm]

Description

Support configuring routers for inbound and outbound directions, based on a RouterId that identify it for both directions

Main changes of this PR:

• Added pallet-axelar-router which connects in both directions with Axelar. It allows the configuration of different domains under Axelar for inbound and outbound messages. It is a mix of axelar-gateway-preocompile and routers/axelar_evm which will be removed.

• Added RouterId. It is like Domain but with information about by where the message needs to be sent.

• Added MessageSender trait and MessageReceiver. The middleware parameter represents by where the message must be sent. Normally, it will be the RouterId but not mandatory, it could be any subset of RouterId, i.e: AxelarId.

• Added a RouterSupport trait (name can change), to allow mapping any Domain in a list of supported routers that can lead the message to that Domain. Will be used by the gateway to obtain the RouterId list for a Domain.

• Added RouterDispatcher in runtime level to redirect a message to the correct router_id.

Use case we want to support

Suppose gateway is configured with the following (dynamically configured by an operator):

• AxelarXcm
• AxelarEvm
• SnowbridgeEvm

And the chain offers the following routers (statically configured in the runtime):

• AxelarXcm
• AxelarEvm
• SnowbridgeEvm
• OtherEvm

If a message with Domain::Evm needs to be sent, it must be sent only to AxelarEvm and SnowbridgeEvm.

• AxelarXcm will not used because that router is not retrieved by for_domain(Domain::Evm)
• OtherEvm will not used because it's not configured in the gateway

[wischli]

Overall, the design looks really good! I am mostly curious on how to extend this to support message relaying, see my long comment.

[cdamian]

I like how this is implemented, thank you for taking care @lemunozm!

[lemunozm]

List of pendings todos

[lemunozm]

If nothing wrong CI should be green with the commented sections in the code

[codecov]

Codecov Report

Attention: Patch coverage is 50.81967% with 60 lines in your changes missing coverage. Please review.

Project coverage is 47.63%. Comparing base (3def5e9) to head (a59c6aa).

Files	Patch %	Lines
pallets/axelar-router/src/lib.rs	72.22%	20 Missing ⚠️
pallets/liquidity-pools-gateway/src/lib.rs	0.00%	15 Missing ⚠️
runtime/common/src/routing.rs	0.00%	15 Missing ⚠️
libs/mocks/src/router_message.rs	62.50%	3 Missing ⚠️
runtime/altair/src/lib.rs	0.00%	2 Missing ⚠️
runtime/centrifuge/src/lib.rs	0.00%	2 Missing ⚠️
runtime/development/src/lib.rs	0.00%	2 Missing ⚠️
runtime/common/src/gateway.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1958      +/-   ##
==========================================
- Coverage   48.11%   47.63%   -0.48%     
==========================================
  Files         183      183              
  Lines       12926    12904      -22     
==========================================
- Hits         6219     6147      -72     
- Misses       6707     6757      +50     

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[wischli]

Super straight-forward and clear - awesome work! A few nits and one question regarding a test.

[wischli]

LS(uper)M(ega)GTM!

[cdamian]

The multi router PR is based on this and I'm super happy with everything so far.

Awesome job @lemunozm!

[lemunozm]

Thanks for your reviews! Should be merged once CI passes 🤞🏻