Add Orchestrator gRPC API

[NicolasMahe]

Related to #1764

This PR adds the Orchestrator API.

This API requires authentication by verifying a base64-encoded signature of the request, set in the request's metadata using the key mesg_request_signature.

It defines the following RPC functions:

service Event {
  // Stream returns a stream of events that satisfy criteria specified.
  rpc Stream(EventStreamRequest) returns (stream types.Event) {}
}

service Execution {
  // Create an execution on the blockchain.
  rpc Create(ExecutionCreateRequest) returns (ExecutionCreateResponse) {}

  // Stream returns a stream of executions that satisfy specified filter.
  rpc Stream(ExecutionStreamRequest) returns (stream types.Execution) {}
}

service Runner {
  // Register registers a new runner to the Engine.
  // This endpoint should only be called when the runner is ready to receive execution and emit events.
  // This endpoint returns a credential token that must be use to reach the Runner APIs.
  rpc Register(RunnerRegisterRequest) returns (RunnerRegisterResponse) {}

  // Delete a runner from the blockchain.
  rpc Delete(RunnerDeleteRequest) returns (RunnerDeleteResponse) {}
}

Note: the runner register rpc has been moved from Runner API to this Orchestrator API.

[antho1404]

I had some issues with the validation of the pub key. Here is my config.yml file (generated from mesg-foundation/js-sdk#221). The key seems valid but the engines send me an error.

AuthorizedPubKeys[0] must be a valid bech32accpubkey

authorized_pubkeys:
  - mesgtestpub1pakk3s28ym3pjj443e4g3u3jnch04cuhgjdfqx
account:
  mnemonic: >-
    guard paddle nature laptop space patient one wait airport side buffalo
    ceiling prevent ten planet immune sample duty fox box option know slot bone

What am I missing?

[NicolasMahe]

I had some issues with the validation of the pub key. Here is my config.yml file (generated from mesg-foundation/js-sdk#221). The key seems valid but the engines send me an error.

AuthorizedPubKeys[0] must be a valid bech32accpubkey

authorized_pubkeys:
  - mesgtestpub1pakk3s28ym3pjj443e4g3u3jnch04cuhgjdfqx
account:
  mnemonic: >-
    guard paddle nature laptop space patient one wait airport side buffalo
    ceiling prevent ten planet immune sample duty fox box option know slot bone

What am I missing?

Your pubkey seems truncated. The one I'm using is much longer: mesgtestpub1addwnpepqwl7axwafcqnc9z92eyrl835w6j54r8806x3lnnqedydt47j6papjmn0439

[NicolasMahe]

i will do this in an other PR. Same for https://github.com/mesg-foundation/engine/pull/1771/files#diff-d7befae5ac5d72ce8456da5eae6f2500R117-R118

[antho1404]

Is it a good thing to return the error here, shouldn't we have an error channel?
Here the first error will actually stop the whole stream.
Might have the same issue on the runner API which might be more critical

[NicolasMahe]

There is no error channel with gRPC streams. The only way to return the error to the client is to return it as it does.