Fix Local layer to only look at operational resource paths

[gordon-klotho]

Since it's a little hard to parse the test data, here's the test yaml I was using

constraints:
  - node: aws:ecs_service:ecs_service_0
    operator: add
    scope: application
  - node: aws:load_balancer:load-balancer-2
    operator: add
    scope: application
  - operator: must_exist
    scope: edge
    target:
      source: aws:load_balancer:load-balancer-2
      target: aws:ecs_service:ecs_service_0

Which results in (annotated):

provider: aws
resources:
  ecs_service/ecs_service_0:
    children:
      # AZs added because ecs -> subnet -> az is all within the operational side effect (glue) boundary
      - aws:availability_zone:region-0:availability_zone-0
      - aws:availability_zone:region-0:availability_zone-1
      # ECR things via the task definition
      - aws:ecr_image:ecs_service_0-image
      - aws:ecr_repo:ecr_repo-0
      - aws:ecs_cluster:ecs_cluster-0
      - aws:ecs_task_definition:ecs_service_0
      - aws:iam_role:ecs_service_0-execution-role
      - aws:log_group:ecs_service_0-log-group
      - aws:region:region-0
      - aws:subnet:vpc-0:subnet-0
      - aws:subnet:vpc-0:subnet-1
      - aws:vpc:vpc-0
    parent: vpc/vpc-0
    tag: big

  vpc/vpc-0:
    children:
      # VPC includes resource for which it is the namespace
      - aws:internet_gateway:vpc-0:internet_gateway-0
      - aws:route_table:vpc-0:subnet-0-route_table
      - aws:route_table:vpc-0:subnet-1-route_table
      - aws:route_table:vpc-0:subnet-2-route_table
      - aws:route_table:vpc-0:subnet-3-route_table
      - aws:security_group:vpc-0:ecs_service_0-security_group
      - aws:subnet:vpc-0:subnet-0
      - aws:subnet:vpc-0:subnet-1
      - aws:subnet:vpc-0:subnet-2
      - aws:subnet:vpc-0:subnet-3
    tag: parent

  load_balancer/load-balancer-2:
    children:
      - aws:availability_zone:region-0:availability_zone-0
      - aws:availability_zone:region-0:availability_zone-1
      - aws:region:region-0
      - aws:subnet:vpc-0:subnet-0
      - aws:subnet:vpc-0:subnet-1
      - aws:vpc:vpc-0
    parent: vpc/vpc-0
    tag: big

  load_balancer/load-balancer-2 -> ecs_service/ecs_service_0:
    path:
      # resources included in any path from load_balancer to ecs_service
      - aws:load_balancer_listener:load-balancer-2-ecs_service_0
      - aws:security_group:vpc-0:ecs_service_0-security_group
      - aws:subnet:vpc-0:subnet-0
      - aws:subnet:vpc-0:subnet-1
      - aws:target_group:load-balancer-2-6c8c4811

[jhsinger-klotho]

Is the glue layer used in any templates today or in path selection anywhere? As afar as i can tell i see it used in determining the candidate weight

klotho/pkg/engine2/path_selection/candidate_weight.go

Line 32 in f4b6669

downstreams, err := solution_context.Downstream(ctx, src, knowledgebase.ResourceGlueLayer)

in which case i think we need to be able to separate these search patterns because this will definitely affect path selection.

could we add some unit tests around the glue layer search? i realize our functional tests do cover it so not blocking but would be great to have isolated tests

[gordon-klotho]

in which case i think we need to be able to separate these search patterns because this will definitely affect path selection.

I intentionally changed the glue layer logic instead of implementing it just for the visualizer because I believe the old glue layer logic was incorrect and the new logic is better for what it was intended to be.

could we add some unit tests around the glue layer search? i realize our functional tests do cover it so not blocking but would be great to have isolated tests

Yeah, I was going to add some but decided to post this as soon as I had it working to get an early review. Standby for some tests

[gordon-klotho]