arm64 and amd64 docker builds

Makefile

# Get the machine architecture.
# On arm64 (Apple Silicon M1/M2/etc.), `uname -m` outputs "arm64".
# On amd64 (Intel), `uname -m` outputs "x86_64".
ARCH := $(shell uname -m)

ifeq ($(ARCH), arm64)
        this_arch=arm64
else ifeq ($(ARCH), x86_64)
        this_arch=amd64
else
        @echo "Unknown architecture: $(ARCH). Cannot determine if Mac is new or old."
endif

docker push multiple platforms using buildx

I wasn't able to get docker manifest to amend both amd64 and arm64, so I used the buildx approach:

docker buildx build --push --platform linux/arm64,linux/amd64 --tag benislocated/allofphysicscom-flask:latest .

References

https://www.docker.com/blog/multi-arch-build-and-images-the-simple-way/