crystal smallest docker file

Dockerfile

# FROM alpine:latest as builder

# RUN apk add -u crystal shards libc-dev

# WORKDIR /src

# COPY . .

# RUN crystal build --release src/api_demo.cr -o /src/api_demo

# FROM busybox

# WORKDIR /app

# COPY --from=builder /src/api_demo /app/api_demo

# ENTRYPOINT ["/app/api_demo"]

FROM crystallang/crystal:latest as builder

WORKDIR /src

COPY . .

RUN shards build --production --progress --verbose --warnings=all
RUN ldd ./bin/api_demo | tr -s '[:blank:]' '\n' | grep '^/' | xargs -I % sh -c 'mkdir -p $(dirname deps%); cp % deps%;'
RUN find ./deps/
RUN ls /src/bin

FROM scratch

COPY --from=builder /src/deps /
COPY --from=builder /lib/x86_64-linux-gnu/libnss_dns.so.* /lib/x86_64-linux-gnu/
COPY --from=builder /lib/x86_64-linux-gnu/libresolv.so.*  /lib/x86_64-linux-gnu/

COPY --from=builder /src/bin/api_demo /app


ENTRYPOINT [ "/app" ]