Install fclones on a Rust-less system using Rust in Docker

fclones-build.sh

#! /usr/bin/env bash
#
# Install fclones on a Rust-less system using Rust in Docker.
#
set -e
set -u
set -x

# latest stable release
FC_TAG=v0.35.0
RUST_VER=1-trixie
MACH=$(uname --machine)
TARGET="$MACH-unknown-linux-musl"

main() {
    src
    cd fclones.git
    git switch --detach $FC_TAG

    img
    bld

    ins
    cd ..
    cln
}

src() {
    ! test -d fclones.git ||return 0
    git clone git@github.com:pkolaczk/fclones.git fclones.git
}

img() {
    docker pull rust:$RUST_VER
    docker build -t build-fclones - <<-EOF
	FROM rust:$RUST_VER

	# give make build proper perms in .:/fclones
	RUN useradd --uid $UID --user-group \
	    --create-home --shell /bin/bash $USER

        # needed so we can build static
	RUN rustup target add $TARGET

	WORKDIR /fclones
	EOF
}

bld() {
    # TODO: --user-group above doesn't always mean :$UID below
    docker run --rm \
      --volume "$PWD:/fclones" \
      --user "$UID:$UID" \
      build-fclones \
      cargo build --release --target="$TARGET"
}

ins() {
    mkdir --parents ~/.local/bin
    cp --force --preserve "target/$TARGET/release/fclones" ~/.local/bin/
}

cln() {
    rm --force --recursive fclones.git
    docker image rm build-fclones
}

main
exit 0