This Dockerfile allows you to compile static linux crystal binaries on any system that supports docker. The dockerhub repo can be found here:
https://hub.docker.com/r/durosoft/crystal-alpine/
Tags exist on the repo for every version of crystal since 0.25.0. Builds are not automated so every distinct tag should work properly.
Build the local file test.cr statically with the latest version of crystal:
docker run --rm -it -v $PWD:/app -w /app durosoft/crystal-alpine:latest crystal build test.cr -o output --release --static --no-debug
Build the local file test.cr statically with crystal 0.25.0:
docker run --rm -it -v $PWD:/app -w /app durosoft/crystal-alpine:0.25.0 crystal build test.cr -o output --release --static --no-debug