Install dependencies:
shards install --production
Build with shards:
shards build --production --release --no-debug
Build with crystal (warning: binaries will be output in the current directory, not in bin/):
crystal build src/*.cr --release --no-debug
Install dependencies:
shards install --production
As the Crystal documentations says:
Building fully statically linked executables is currently only supported on Alpine Linux.
For that purpose, the documentation recommends using musl-libc:
Official Docker Images based on Alpine Linux are available on Docker Hub at crystallang/crystal. The latest release is tagged as crystallang/crystal:latest-alpine.
As an example replace the local build:
# With Shards (in bin/)
shards build --production --release --static --no-debug
# With Crystal (in ./)
crystal build src/*.cr --release --static --no-debug
with
# With Shards (in bin/)
docker run --rm -it -v $PWD:/workspace -w /workspace crystallang/crystal:1.12.1-alpine \
shards build --production --release --static --no-debug
# With Crystal (in ./)
docker run --rm -it -v $PWD:/workspace -w /workspace crystallang/crystal:1.12.1-alpine \
crystal build src/*.cr --release --static --no-debug
Since you are cross-compiling from a docker container, it would be wiser to ensure to provide the correct cross compilation flags.
Find your platform with llvm-config --host-target (examples: x86_64-pc-linux-gnu on a modern Linux host) on your host or the target (see platform support and LLVM - Cross-compilation using Clang).
So change from (unfortunately shards doesn’t support cross-compilation)
crystal build src/*.cr --release --static --no-debug --cross-compile --target x86_64-pc-linux-gnu
cc *.o -o * -rdynamic -static -L/usr/bin/../lib/crystal -lpcre2-8 -lgc -lpthread -ldl -lpthread -levent -lrt -lpthread -ldl
to
docker run --rm -it -v $PWD:/workspace -w /workspace crystallang/crystal:1.12.1-alpine \
crystal build src/*.cr --release --static --no-debug \
-o bin/*-x86_64-pc-linux-gnu --cross-compile --target x86_64-pc-linux-gnu
cc bin/*-x86_64-pc-linux-gnu.o -o bin/*-x86_64-pc-linux-gnu -rdynamic -static -L/usr/bin/../lib/crystal -lpcre -lm -lgc -lpthread -levent -lrt -lpthread -ldl
Note: the second line must be executed on the target platform.
Finally, check your binary is fully static:
ldd bin/*-x86_64-pc-linux-gnu
not a dynamic executable
Note: of course, you need to replace * with the name of a utility. For more convenience, cross_compile_objects.cr (crystal run cross_compile_objects.cr) script will compile all pre-compiled objects for all tier 1 & 2 platforms.
With this we can compile a pre-compiled object without needing Crystal, Docker or managing the dependencies.
cc *-x86_64-linux-gnu.o -o *-x86_64-linux-gnu -rdynamic -static -L/usr/lib/crystal -lpcre -lm -lgc -lpthread -levent -lrt -lpthread -ldl
cc *-aarch64-linux-gnu.o -o *-aarch64-linux-gnu -rdynamic -static -L/usr/lib/crystal -lpcre -lm -lgc -lpthread -levent -lrt -lpthread -ldl
cc *-aarch64-linux-musl.o -o *-aarch64-linux-musl -rdynamic -static -L/usr/lib/crystal -lpcre -lgc -levent
Dependencies Debian 11: apt install libpcre3-dev libgc-dev libevent-dev
cc *-arm-linux-gnueabihf.o -o *-arm-linux-gnueabihf -rdynamic -static -L/usr/lib/crystal -lpcre -lm -lgc -lpthread -levent -lpthread -ldl
cc *-i386-linux-gnu.o -o *-i386-linux-gnu -rdynamic -static -L/usr/lib/crystal -lpcre -lm -lgc -lpthread -levent -lrt -lpthread -ldl
cc *-i386-linux-musl.o -o *-i386-linux-musl -rdynamic -static -L/usr/lib/crystal -lpcre -lgc -levent
cc *-x86_64-linux-musl.o -o *-x86_64-linux-musl -rdynamic -static -L/usr/lib/crystal -lpcre -lgc -levent
cc *-x86_64-openbsd.o -o *-x86_64-openbsd -rdynamic -static -L/usr/lib/crystal -lpcre -lm -lgc -lpthread -levent_extra -levent_core -lc++abi -lpthread -liconv
cc *-x86_64-freebsd.o -o *-x86_64-freebsd -rdynamic -static -L/usr/lib/crystal -lpcre -lm -lgc-threaded -lpthread -levent -lpthread
cc *-x86_64-darwin.o -o *-x86_64-darwin -rdynamic -static -L/usr/lib/crystal -lpcre -lgc -levent -liconv
cc *-aarch64-darwin.o -o *-aarch64-darwin -rdynamic -static -L/usr/lib/crystal -lpcre -lgc -levent -liconv