version: "3"

name: my-project-name

services:
  env-test:
    image: busybox
    command: sh -c "export | grep ZZ"
    environment:
      ZZVAR1: myval1
      ZZVAR2: 2-$ZZVAR1
      ZZVAR3: 3-$ZZVAR2

  project-name-test:
    image: busybox
    command: sh -c "echo $$PNAME"
    environment:
      PNAME: ${COMPOSE_PROJECT_NAME}