Sharing Variables between GNU Make and the Bash

.envrc

file=$(cat env)

for line in $file; do
	export "${line}"
done

docker-compose.myproject.yaml

---
version: '3'

services:
  nginx:
    image: nginx:1.16.0-alpine
    ports:
      - "8080:80"

env

COMPOSE_FILE=docker-compose.myproject.yaml
DOCKER_CONTEXT=default
COMPOSE_PROJECT_NAME=myproject

Makefile

include env
export

all:
	@echo $(COMPOSE_FILE)

up:
	docker compose up -d

down:
	docker compose down -v