GCP Cloud Build - multiple builds from directories

gcp-cloud-build-multiple.yaml

# If a directory has a cb-deploy.yaml file, it will run for CD
steps:
- name: 'gcr.io/cloud-builders/gcloud'
  entrypoint: 'bash'
  args:
  - '-c'
  - |
    for d in */; do
      config="${d}cb-deploy.yaml"
      if [[ ! -f "${config}" ]]; then
        continue
      fi

      echo "Building and deploying $d ... "
        if [[ -z "${SHORT_SHA}" ]]
        then
          echo "==== $SHORT_SHA NOT FOUND - USING CLOUD BUILD LOCAL ===="
          cloud-build-local --config=cb-deploy.yaml --dryrun=false --push $d
        else
          (
            gcloud builds submit $d --config=${config}
          ) &
        fi
    done
    wait
options:
  substitution_option: 'ALLOW_LOOSE'

Unfortunately, without a custom builder, this won't work with Cloud Build Local because cloud-build-local requires Docker.... Docker in Docker.