Parameterize a multi-stage Docker build output using ARG and ENV

build.sh

docker build --build-arg MODULE=my_app -t my_app .

Dockerfile

# Build the $MODULE target (which produces a $MODULE binary)
FROM debian:latest as builder

ARG MODULE
COPY src/ .
RUN make ${MODULE}


# Build a minimal image containing the $MODULE binary
FROM alpine:latest as product

## important! declare MODULE for each stage where you need to use it
ARG MODULE

COPY --from=builder /${MODULE} /

# Define an environnement variable $CALL_MODULE in the image
ENV CALL_MODULE=${MODULE}
# Docker does not substitute variable in ENTRYPOINT instruction
# So we define an environnement variable inside the image which will be the ENTRYPOINT
ENTRYPOINT /${CALL_MODULE}