river/PACKAGING.md
2022-05-22 15:35:42 +02:00

4.4 KiB

Packaging river for distribution

First of all, I apologize for writing river in Zig. It will likely make your job harder until Zig is more mature/stable. I do however believe that writing my software in Zig allows me to deliver the best quality I can despite the drawbacks of depending on a relatively immature language/toolchain.

Source tarballs

Source tarballs with stable checksums and git submodule sources included may be found on the github releases page. These tarballs are signed with the PGP key available on my website at https://isaacfreund.com/public_key.txt.

For the 0.1.3 release for example, the tarball and signature URLs are:

https://github.com/riverwm/river/releases/download/v0.1.3/river-0.1.3.tar.gz
https://github.com/riverwm/river/releases/download/v0.1.3/river-0.1.3.tar.gz.sig

Zig version

Until Zig 1.0, Zig releases will often have breaking changes that prevent river from building. River tracks the latest minor version Zig release and is only compatible with that release and any patch releases. At the time of writing for example river is compatible with Zig 0.9.0 and 0.9.1 but not Zig 0.8.0 or 0.10.0.

Build options

River is built using the Zig build system. To see all available build options run zig build --help.

Important: By default Zig will build for the host system/cpu using the equivalent of -march=native. To produce a portable binary -Dcpu=baseline at a minimum must be passed.

Here are a few other options that are particularly relevant to packagers:

  • -Dcpu=baseline: Target the baseline CPU, or any other set of CPU features.

  • -Dtarget=x86_64-linux-gnu: Target architecture, OS, and ABI triple. See the output of zig targets for an exhaustive list of targets and CPU features, use of jq(1) to inspect the output recommended.

  • -Dpie: Build a position independent executable.

  • -Dstrip: Build without debug info. This not the same as invoking strip(1) on the resulting binary as it prevents the compiler from emitting debug info in the first place. For greatest effect, both may be used.

  • --sysroot /path/to/sysroot: Set the sysroot for cross compilation.

  • --libc my_libc.txt: Set system libc paths for cross compilation. Run zig libc to see a documented template for what this file should contain.

  • Enable compiler optimizations:

    • -Drelease-safe: Keep all assertions and runtime safety checks active.

    • -Drelease-fast: Optimize for execution speed, disable all assertions and runtime safety checks.

    • -Drelease-small: Optimize for binary size, disable all assertions and runtime safety checks.

Please use -Drelease-safe when building river for general use. CPU execution speed is not the performance bottleneck for river, the GPU is. Additionally, the increased safety is more than worth the binary size trade-off in my opinion.

Build prefix and DESTDIR

To control the build prefix and directory use --prefix and the DESTDIR environment variable. For example

DESTDIR="/foo/bar" zig build --prefix /usr install

will install river to /foo/bar/usr/bin/river.

The Zig build system only has a single install step, there is no way to build artifacts for a given prefix and then install those artifacts to that prefix at some later time. However, much existing distribution packaging tooling expect separate build and install steps. To fit the Zig build system into this tooling, I recommend the following pattern:

build() {
    DESTDIR="/tmp/river-destdir" zig build --prefix /usr install
}

install() {
    cp -r /tmp/river-destdir/* /desired/install/location
}

Examples

Build for the host architecture and libc ABI:

DESTDIR=/foo/bar zig build -Drelease-safe -Dcpu=baseline \
    -Dstrip -Dpie --prefix /usr install

Cross compile for aarch64 musl libc based linux:

cat > xbps_zig_libc.txt <<-EOF
    include_dir=${XBPS_CROSS_BASE}/usr/include
    sys_include_dir=${XBPS_CROSS_BASE}/usr/include
    crt_dir=${XBPS_CROSS_BASE}/usr/lib
    msvc_lib_dir=
    kernel32_lib_dir=
    gcc_dir=
EOF

DESTDIR="/foo/bar" zig build \
    --sysroot "${XBPS_CROSS_BASE}" \
    --libc xbps_zig_libc.txt \
    -Dtarget=aarch64-linux-musl -Dcpu=baseline \
    -Drelease-safe -Dstrip -Dpie \
    --prefix /usr install

Questions?

If you have any questions feel free to reach out to me at mail@isaacfreund.com or in #zig or #river on irc.libera.chat, my nick is ifreund.