Dockerizing our Heroku apps

Dockerfile

ARG STACK_VERSION=20

FROM gliderlabs/herokuish:latest-${STACK_VERSION} AS build
COPY . /tmp/app
ARG NPM_TOKEN
ENV NODE_ENV=production

RUN (cat /tmp/app/app.json || echo '{}') | jq -r '.buildpacks[].url' > /tmp/app/.buildpacks && \
    (test -s /tmp/app/.buildpacks || rm /tmp/app/.buildpacks)
RUN /build && \
    rm -Rf /tmp/* && \
    rm -Rf /app/.npmrc
RUN herokuish slug generate && \
    herokuish slug export > /app.tar.gz

FROM gliderlabs/herokuish:latest-${STACK_VERSION}
ENV PORT 3000
ENV NODE_ENV=production
COPY --from=0 /etc /etc
RUN --mount=type=bind,from=build,source=/app.tar.gz,target=/app.tar.gz \
    herokuish slug import < /app.tar.gz
ENTRYPOINT [ "/start" ]
CMD [ "web" ]

Makefile

APP_NAME?=some-app
APP_NAMESPACE?=default
IMAGE_NAME?="ambassify/$(APP_NAME)"

export DOCKER_BUILDKIT = 1

up: build
	docker run -t -i \
		-e PORT=3000 \
		-p 3000:3000/tcp \
		$(IMAGE_NAME)

pull:
	docker pull gliderlabs/herokuish

build: pull
	docker build --build-arg NPM_TOKEN -t $(IMAGE_NAME) .

debug: build
	docker run -t -i --entrypoint /bin/bash $(IMAGE_NAME)

publish: build
	docker tag $(IMAGE_NAME) ghcr.io/$(IMAGE_NAME)
	docker push ghcr.io/$(IMAGE_NAME)

deploy: publish
	kubectl rollout restart deployment $(APP_NAME) -n $(APP_NAMESPACE)