Can't create two lambdas using the same eventBus

Bug Report

Description

Create two lambda functions using the same eventBus on EventBridge service gives an error that eventBus cannot be created.

1. What did you do? Try to create two lambda functions using the same event bus

2. What happened? Gives an error failed to create resource already exists

3. What should’ve happened? Create the two lambdas using the same eventBus

4. What’s the content of your serverless.yml file?

service: my-service

provider:
  name: aws
  stage: ${opt:stage}
  runtime: go1.x
  region: us-east-1

package:
  exclude:
  stage: ${opt:stage}
    - ./**
  include:
    - ./bin/**

functions:
  plans-create:
    handler: bin/eventbridge/plans/create
    events:
      - eventBridge:
          eventBus: mybus-${opt:stage}
          pattern:
            source:
            - prod.admin.plans
            detail-type:
            - plan-created

  plans-update:
    handler: bin/eventbridge/plans/update
    events:
      - eventBridge:
          eventBus: mybus-${opt:stage}
          pattern:
            source:
              - prod.admin.plans
            detail-type:
              - plan-updated

Failed to create resource. Event bus mybus-dev already exists.

Similar or dependent issues:

• #1842

[eduardonunesp]

Ok find a way to workaround this, like the following example, but it needs at least the arn:aws to work

custom:
  accountNumber: 123456789
  eventBus: arn:aws:events:us-east-1:${self:custom.accountNumber}:event-bus/mybus-${opt:stage}

functions:
  plans-create:
    handler: bin/eventbridge/plans/create
    events:
      - eventBridge:
          eventBus: ${self:custom.eventBus}
          pattern:
            source:
            - prod.admin.plans
            detail-type:
            - plan-created

resources:
  Resources:
    EventBridgeBus:
      Type: AWS::Events::EventBus
      Properties:
          Name: mybus-${opt:stage}

[michalorman]

@TreeMan360 Got the same EventBus.startsWith is not a function error with:

    events:
      - eventBridge:
          eventBus:
            Fn::GetAtt: [EventBus, Arn]

The event bus is being created fine when using resources, but I can’t reference with GetAtt.

So far I’m having 2 issues:

1. Creating 2 lambdas using same eventBus with a custom name (according to serverless documentation it automatically creates event bus in such case) raises Cloud Formation error that EventBus is already created.
2. Creating custom eventBus in resources section I can’t reference it with !GetAtt nor Fn::GetAtt.

I can work this around with the custom attribute hardcoding the ARN as Eduardo did in this thread, but would be good to do it in more declarative way rather than hardcoding ARN’s.