[Proxy] feat: implement relayer proxy full workflow

[red-0ne]

Summary

Human Summary

Implemented the needed parts of the RelayerProxy flow which involves:

• Building the RelayRequest from the http.Request
• Verifying the RelayRequest signature and session
• Forwarding the request to the native service
• Building the RelayReponse and signing it
• Replying to the requester
• Notifying the serverdRelays observable
• Replying appropriately if any error happens

It assumes the availability BlockClient and Session query client with the appropriate SessionHeader fields (available when PRs #78 and #65 get merged)

AI Summary

Summary generated by Reviewpad on 08 Nov 23 22:31 UTC

This pull request includes various changes across multiple files in the codebase. Here's a summary of the changes:

1. In the file "file_diff.go":

   • Updated imports to include the packages "github.com/pokt-network/poktroll/pkg/relayer" and "github.com/pokt-network/poktroll/x/supplier/types".
   • Added a new variable "rp.supplierAddress" and modified the types of two variables: "serviceEndpoints" and "server" to use types from the "relayer" package.

2. In the file "relay_signer.go":

   • Introduced a new file that contains a method to sign the hash of the RelayResponse.
   • The method relies on the keyring and keyName to sign the payload and returns the signature.
   • There are TODO_TECHDEBT comments suggesting improvements for the method.

3. In the file "interface.go":

   • Added new imports and defined interfaces for managing relay servers and relay sessions.
   • These interfaces provide methods for starting and stopping relay servers, retrieving served relays, and managing SMSTs.
   • Removed unused methods and modified existing type declarations.

4. In the file "error_reply.go":

   • Introduced a new file that contains a method to generate and write JSONRPC error responses.
   • The method builds an error response based on the input error and writes it to the HTTP ResponseWriter.
   • There are TODO_TECHDEBT comments suggesting improvements for the method.

5. In the file "other_file_diff.go":

   • Added imports for various packages.
   • Updated type declarations and added new methods.
   • Removed an unused interface.

6. In the file "interface.go":

   • This file has been deleted. It contained interfaces for managing relay servers and relaying requests, which are no longer needed.

7. In the file "proxy_test.go":

   • Introduced a new file that contains tests for the "relayerProxy" and its jsonRPC component.
   • There is a TODO comment suggesting adding more tests.

8. In the file "relay.proto":

   • Made changes to import statements and uncommented a message field in the RelayRequestMetadata message and the RelayResponseMetadata message.

9. In the file "jsonrpc.go":

   • Made changes related to implementing a JSON-RPC server for relaying requests.
   • Added imports, changed type assertions, and added new methods.
   • Modified the logic for serving relay requests and sending responses.

10. In the file "relay_verifier.go":

    • Introduced a new file that contains a method to verify relay requests.
    • The method checks the relay request signature, session validity, and whether the relayer proxy can serve the request.
    • TODO comments suggest areas for further investigation.

11. In the file "errors.go":

    • Made changes to define new error variables for specific error scenarios.

12. In the file "new_file.go":

    • Added a new file that contains functions for building RelayRequest and RelayResponse objects from HTTP requests and responses.
    • The functions handle marshaling and unmarshaling of JSON data.

Please let me know if you need more information.

Issue

• [Proxy] Foundation for the Proxy submodule #14

Type of change

Select one or more:

• New feature, functionality or library
• Bug fix
• Code health or cleanup
• Documentation
• Other (specify)

Testing

• Run all unit tests: make go_test
• Verify Localnet manually: See the instructions [here](TODO: add link to instructions)

Sanity Checklist

• I have tested my changes using the available tooling
• I have performed a self-review of my own code
• I have commented my code, updated documentation and left TODOs throughout the codebase

[Olshansk]

Just left one update in a TODO comment, but otherwise really clean and g2g!

[Olshansk]

@bryanchriswhite After you merge in #65, let's try to rebase & update this PR as it should be g2g.

[Olshansk]

@red-0ne Please merge (and fix conflicts) with main, and will re-review then.

Please also add *_test.go files with a TODO_TEST comment where applicable explaining that we're biasing towards an E2E relay and that building test utilities for these off-chain components is a non-trivial amount of work.

[Olshansk]

Reviewed everything with the exception of pkg/relayer/proxy/relay_verifier.go. Going to check that out tomorrow. Great work!

[red-0ne]

This PR should be merged after #150

[red-0ne]

@h5law , we switched from only signing the RelayResponse payload to signing the whole response (including session headers). Please make sure to reflect this in the AppGate response verification.

[Olshansk]

I think it's kind of confusing that:

1. We pass in a pointer to an object
2. That pointer may be mutated
3. We return it

I believe it should be one of:

1. Pass a pointer that may be mutated
2. Pass a value that's copied, mutated, and returned

[red-0ne]

I see... I'll revert to passing the pointer without returning and mutate it inside the function as I can't clearly foresee the impact of changing the whole workflow to not use pointers. We'll keep that question to when we start implementing the middleware capabilities.

[red-0ne]

cc @bryanchriswhite

[Olshansk]

@red-0ne Also, please update this PR w/ main