#17539 Build docker image for specific platform New issue created by huonw Is your feature request related to a problem? Please describe. A docker image can be targeted to a specific platform, e.g.

linux/amd64

will run on x86-64 Linux systems, while

linux/arm64

will run on AArch64 ones. This can be configured via the

--platform

argument to

docker build

, and defaults to the current platform: https://docs.docker.com/engine/reference/commandline/build/#options . This means that an uncustomised

docker build

on ARM (e.g. macOS with Apple Silicon) will build for

linux/arm64

. It'd be nice to be able to control the platform for a

docker_image

, so that, for example, docker images that are deployed on

amd64

can be built for that platform, independent of the host. Currently, we're having to have two complete platforms JSON specs (one for amd64 and one for arm64), and build our dependency PEX for both (following https://blog.pantsbuild.org/optimizing-python-docker-deploys-using-pants/ and/or https://pex.readthedocs.io/en/v2.1.113/recipes.html#pex-app-in-a-container), which ~doubles the size of the resulting PEX, takes longer to download from a cache, and takes longer to manipulate. Describe the solution you'd like A

platform

(or similar) argument to

docker_image

that is passed through as

docker build --platform ...

. Describe alternatives you've considered I don't know of one. Additional context N/A pantsbuild/pants