Create Linux release version with Docker.

Dockerfile

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+FROM crystallang/crystal:0.36.1-alpine
+WORKDIR /app
+COPY . .
+
+# dependencies
+RUN apk add libmagic
+
+# work around alpine not shipping with static libmagic.a
+RUN apk add libtool autoconf automake
+RUN mkdir -p /opt/src
+# zlib
+RUN cd /opt/src && git clone https://github.com/madler/zlib.git && cd zlib && ./configure --static --64 && make
+# bz2
+RUN cd /opt/src && git clone git://sourceware.org/git/bzip2.git && cd bzip2 && make
+# file/libmagic
+RUN cd /opt/src && git clone https://github.com/file/file.git
+RUN cd /opt/src/file && SH_LIBTOOL='/usr/share/build-1/libtool' autoreconf -f -i
+RUN cd /opt/src/file && CFLAGS="-static" ./configure --prefix=/usr --datadir=/usr/share --enable-static --disable-xzlib
+RUN cd /opt/src/file && make LDFLAGS="-all-static"
+
+# by default just run the tests
+CMD ["crystal", "spec"]

scripts/console_docker

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+#!/usr/bin/env bash
+
+docker run -it --entrypoint /bin/sh -v "$PWD":/workspace -w /workspace lister:latest

scripts/release

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+#!/usr/bin/env bash
+
+thispath="$(dirname "${BASH_SOURCE[0]}")"
+
+cd "$thispath"/.. || exit 1
+
+command_exists() { command -v "$1" > /dev/null 2>&1; }
+#find_libd () { dirname "$(find /usr/lib /opt /usr/local/opt -name "*lib$1.so*" -quit 2> /dev/null;)"; }
+find_liba () { find /usr/lib /opt /usr/local/opt -name "*lib$1.a*" -quit 2> /dev/null; }
+
+if command_exists osinfo.bash; then
+  OS=$(osinfo.bash)
+else
+  OS=$(uname)
+fi
+
+# Linker flags, primarily useful for static builds but also for systems which don't have libraries in the normal search path
+if command_exists brew; then
+  # MacOS Linker flags from Homebrew
+  echo "Pulling library dependencies from Homebrew..."
+  LINK_FLAGS="$(brew --prefix zlib)/lib/libz.a $(brew --prefix bzip2)/lib/libbz2.a $(brew --prefix libmagic)/lib/libmagic.a"
+else
+  # ideally these should be pulled in for any OS
+  echo "Looking for libraries, this might take some time, especially if they're missing!"
+  LINK_FLAGS="-lmagic -lz -lbz2 $(find_liba magic) $(find_liba z) $(find_liba bz2)"
+fi
+
+echo "Building standard release for native platform ($OS)..."
+crystal build src/lister.cr -o "bin/lister.$OS" --release --no-debug
+echo "Building libmagic-static release for native platform ($OS)..."
+crystal build src/lister.cr -o "bin/lister.static.$OS" --release --no-debug --link-flags "$LINK_FLAGS"
+
+# for the docker image with known locations
+ALPINE_LINK_FLAGS="-lmagic -lz -lbz2 -L /opt/src/file/src/.libs -L /opt/src/zlib -L /opt/src/bzip2"
+
+echo "Building standard release for Linux x86_64..."
+docker run --rm -it -v "$PWD":/workspace -w /workspace lister:latest \
+    crystal build src/lister.cr -o "bin/lister.alpine" --release --no-debug --link-flags "$ALPINE_LINK_FLAGS"
+echo "Building static release for Linux x86_64..."
+docker run --rm -it -v "$PWD":/workspace -w /workspace lister:latest \
+    crystal build src/lister.cr -o "bin/lister.static.alpine" --static --release --no-debug --link-flags "$ALPINE_LINK_FLAGS"