build.rs

use fs_extra::dir;
use fs_extra::dir::CopyOptions;
use std::env;
use std::fs;
use std::path::{Path, PathBuf};

const MANIFEST_TEMPLATE_NAME: &str = "manifest.yaml.template";

#[cfg(target_os = "linux")]
const LIB_EXT: &str = "so";

#[cfg(target_os = "macos")]
const LIB_EXT: &str = "dylib";

fn get_output_path() -> PathBuf {
    let manifest_dir_string = env::var("CARGO_MANIFEST_DIR").unwrap();
    let build_type = env::var("PROFILE").unwrap();
    Path::new(&manifest_dir_string)
        .join("target")
        .join(build_type)
}

fn main() {
    let crate_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
    let crate_dir = Path::new(&crate_dir);

    let template_path = crate_dir.join(MANIFEST_TEMPLATE_NAME);
    let template =
        fs::read_to_string(template_path).expect("template for manifest plugin not found");
    let template = liquid::ParserBuilder::with_stdlib()
        .build()
        .unwrap()
        .parse(&template)
        .expect("invalid manifest template");

    let migrations_dir = crate_dir.join("migrations");
    let migrations: Vec<String> = fs::read_dir(&migrations_dir)
        .unwrap()
        .map(|path| {
            path.unwrap()
                .path()
                .strip_prefix(crate_dir)
                .unwrap()
                .to_string_lossy()
                .into()
        })
        .collect();

    let pkg_version = env::var("CARGO_PKG_VERSION").unwrap();

    let template_ctx = liquid::object!({
        "version": pkg_version,
        "migrations": migrations,
    });

    let out_dir = get_output_path();
    let out_manifest_path = Path::new(&out_dir).join("manifest.yaml");
    fs::write(&out_manifest_path, template.render(&template_ctx).unwrap()).unwrap();

    let mut cp_opts = CopyOptions::new();
    cp_opts.overwrite = true;
    dir::copy(migrations_dir, &out_dir, &cp_opts).unwrap();

    // create symbolic link
    let pkg_name = env::var("CARGO_PKG_NAME").unwrap();
    let plugin_path = out_dir.join(&pkg_name).join(pkg_version);
    dir::remove(&plugin_path).unwrap();
    fs::create_dir_all(&plugin_path).unwrap();
    std::os::unix::fs::symlink(out_manifest_path, plugin_path.join("manifest.yaml")).unwrap();
    let lib_name = format!("lib{}.{}", pkg_name, LIB_EXT);
    std::os::unix::fs::symlink(out_dir.join(&lib_name), plugin_path.join(lib_name)).unwrap();
    std::os::unix::fs::symlink(out_dir.join("migrations"), plugin_path.join("migrations")).unwrap();

    for m in &migrations {
        println!("cargo::rerun-if-changed={m}");
    }

    println!("cargo::rerun-if-changed={MANIFEST_TEMPLATE_NAME}");
}