Dockerfile snippet to detect platform arch

dockerfile_detect_platform_arch

FROM ubuntu:latest

ARG PLATFORM_ARCH=

RUN case "$(uname -m)" in \
      x86_32) export PLATFORM_ARCH='386' ;; \
      x86_64) export PLATFORM_ARCH='amd64' ;; \
      amd64) export PLATFORM_ARCH='amd64' ;; \
      armhf) export PLATFORM_ARCH='arm' ;; \
      armv7) export PLATFORM_ARCH='arm' ;; \
      aarch64) export PLATFORM_ARCH='arm64' ;; \
      arm64) export PLATFORM_ARCH='arm64' ;; \
      *) echo >&2 "error: unsupported architecture ($PLATFORM_ARCH)"; exit 1 ;; \
    esac; \
    echo "Detected System Architecture \"$PLATFORM_ARCH\""