Dockerfile arm architecture

[PeterSurda]

The buildscripts/docker/Dockerfile.bionic doesn't work on arm architecture (Apple M1, Raspberry Pi, ...).

[PeterSurda]

Update on how to deal with this:

• it helps if you use BuildKit for building. You can enable it by export DOCKER_BUILDKIT=1 before running docker build
• if BuildKit is enabled, add a new line with ARG TARGETARCH just after the top FROM
• if BuildKit isn't enabled, you need to add the TARGETARCH argument into the command line when executing the command line manually
• then the $TARGETARCH argument in the rest of the Dockerfile can be used to distinguish between amd64 and arm64. I haven't tested other platforms.
• since Dockerfile syntax doesn't support branching, the way I found to do this is to have a per-architecture stage, for example

# default
ARG TARGETARCH=amd64

# Intel and AMD
FROM base AS deps-amd64
RUN apt install bla bla

# ARM
FROM base AS deps-arm64
RUN apt install bla bla

# next stage
FROM deps-$TARGETARCH AS travis
RUN blabla