Multiple event definitions for existing S3 bucket

[pmuens]

What did you implement:

Closes #6461

Adds support to define multiple S3 events in one function.

How did you implement it:

Fix it and write regression tests.

How can we verify it:

Use the following serverless.yml file or run the S3 integration tests (which were updated as well).

service: test-${self:custom.idx}

provider:
  name: aws
  runtime: nodejs10.x
  versionFunctions: false

custom:
  idx: 0
  bucket: serverless-existing-s3-bucket # replace this with your bucket name

functions:
  created:
    handler: handler.hello
    events:
      - s3:
          bucket: ${self:custom.bucket}
          events: s3:ObjectCreated:*
          rules:
            - suffix: .txt
            - prefix: files
          existing: true
      - s3:
          bucket: ${self:custom.bucket}
          events: s3:ObjectCreated:*
          rules:
            - suffix: .pdf
            - prefix: files
          existing: true
  removed:
    handler: handler.hello
    events:
      - s3:
          bucket: ${self:custom.bucket}
          event: s3:ObjectRemoved:*
          rules:
            - suffix: .txt
            - prefix: files
          existing: true
      - s3:
          bucket: ${self:custom.bucket}
          event: s3:ObjectRemoved:*
          rules:
            - suffix: .pdf
            - prefix: files
          existing: true

The easiest way is to run the integration tests for S3 buckets.

Todos:

Note: Run npm run test-ci to run all validation checks on proposed changes

• Write tests and confirm existing functionality is not broken.
  Validate via npm test
• Ensure there are no lint errors.
  Validate via npm run lint-updated
  Note: Some reported issues can be automatically fixed by running npm run lint:fix
• Ensure introduced changes match Prettier formatting.
  Validate via npm run prettier-check-updated
  Note: All reported issues can be automatically fixed by running npm run prettify-updated
• Make sure code coverage hasn't dropped
• Provide verification config / commands / resources
• Enable "Allow edits from maintainers" for this PR
• Update the messages below

Is this ready for review?: YES
Is it a breaking change?: NO

[anshul1790]

Hi @pmuens, I have tagged you in the same issue which I am facing. It comes when I try to redeploy the YAML file again.
Error says: Failed to create resource. Configuration is ambiguously defined. Cannot have overlapping suffixes in two rules if the prefixes are overlapping for the same event type. See details in CloudWatch Log

#7536