Implement gRPC delegation in Local Hub

[mszostok]

Description

After Investigate existing solutions to speed up Local Hub rewrite task, we decided to give up with Local Hub rewrite. Instead, we will implement our delegated storage in separate Go service and use gRPC in Local Hub to delegate values resolution.

The initial protobufs were defined in https://github.com/capactio/capact/pull/644

Steps

• [x] Distinguish if backend is built-in or not:
  • if external, execute gRPC call to save/lock/unlock/update/delete a given value. (for now context is ignored, will be done in https://github.com/capactio/capact/issues/634)
  • ensure that transaction is aborted in case of any error
  • store returned TypeInstance.backend.context if not empty

    Q: what is the contract here? should delegated storage always return context, even if not modified or not?

• [x] Refactor Local Hub structure to enable its extensibility.
• [x] Refactor the createTypeInstance mutation to use the createTypeInstances. If not possible, remove it and adjust all its usage.
• [x] Refactor Local Hub and extract logic for backend resolution: https://github.com/capactio/capact/blob/f6f487e32a7bcad582cfca2e8ce6847c84dc699b/hub-js/graphql/local/schema.graphql#L386-L401
• [x] Refactor Local Hub and store value only for built-in storage backends
• [x] Execute gRPC call to:
  • create
  • lock/unlock
  • update
  • delete

Additional

• [x] Update Local Hub GraphQL mutations and queries with backend.context property. It should be of type Any!. For example:

  • Mutation

    mutation CreateTypeInstances {
    createTypeInstances(
      in: {
       typeInstances: [
        {
          alias: "helm-release"
          typeRef: { path: "cap.type.helm.chart.release", revision: "0.1.0" }
          value: {
            key: "test" # same as it was
          }
          backend: {
            id: "123" # it's like that already.
            context: { # new property of type `Any!`
              name: "release-name",
              namespace: "release-namespace",
            }
          }
        }
      ]
    }
    ) {
      id
      alias
    }
    }

  • Query

    query GetTypeInstance($typeInstanceID: ID!) {
    typeInstance(id: $typeInstanceID) {
      id
      typeRef {
        path
        revision
      }
      backend { # current backend entry
        id
        abstract
      }    
      lockedBy
      latestResourceVersion {
          resourceVersion
          createdBy
          metadata {
            attributes {
              path
              revision
            }
          }
          spec {
            value
          }
          backend {
            context { # new property of type `Any!`
              name
              namespace
            }
          }
      }
    }
    }

• [x] Validate Storage TypeInstance value - Stretch, if not possible, extract to dedicated task. - extracted to: https://github.com/capactio/capact/issues/656

• Integration tests are out of scope

Related issues

See epic #604 for reason and use cases.

[mszostok]

PRs:

• https://github.com/capactio/capact/pull/649
  • https://github.com/capactio/website/pull/112
• https://github.com/capactio/capact/pull/652
• https://github.com/capactio/capact/pull/654