use std::{env, path::PathBuf}; use xtask::{create_symlink_to_binary, AYA_BUILD_INTEGRATION_BPF}; /// Building this crate has an undeclared dependency on the `bpf-linker` binary. This would be /// better expressed by [artifact-dependencies][bindeps] but issues such as /// https://github.com/rust-lang/cargo/issues/12385 make their use impractical for the time being. /// /// This file implements an imperfect solution: it causes cargo to rebuild the crate whenever the /// mtime of `which bpf-linker` changes. Note that possibility that a new bpf-linker is added to /// $PATH ahead of the one used as the cache key still exists. Solving this in the general case /// would require rebuild-if-changed-env=PATH *and* rebuild-if-changed={every-directory-in-PATH} /// which would likely mean far too much cache invalidation. /// /// [bindeps]: https://doc.rust-lang.org/nightly/cargo/reference/unstable.html?highlight=feature#artifact-dependencies fn main() { println!("cargo:rerun-if-env-changed={}", AYA_BUILD_INTEGRATION_BPF); let build_integration_bpf = env::var(AYA_BUILD_INTEGRATION_BPF) .as_deref() .map(str::parse) .map(Result::unwrap) .unwrap_or_default(); if build_integration_bpf { let out_dir = env::var_os("OUT_DIR").unwrap(); let out_dir = PathBuf::from(out_dir); let bpf_linker_symlink = create_symlink_to_binary(&out_dir, "bpf-linker").unwrap(); println!( "cargo:rerun-if-changed={}", bpf_linker_symlink.to_str().unwrap() ); } }