Explore alternatives to meta-rust-bin

[elBoberido]

Brief

While meta-rust-bin works quite well, it has the disadvantage to require network for the compile task to download the crates. This is not ideal and alternatives shall be explored.

Detail

The recipes with meta-rust-bin requite do_compile[network] = "1" to be set. Alternatives are:

• meta-rust
  • cargo bitbake does not work well with cargo workspaces
    • cargo bitbake is used to create the list of crate dependencies
    • { workspace = true } does not work with cargo bitbake and all values must be duplicated in the respective Cargo.toml
    • a virtual workspace also does not work with cargo bitbake but only on the members, e.g. iceoryx2-ffi/c
  • meta-rust must be placed before meta in bblayers.conf
    • if not placed before meta, it conflicts with the shipped Rust 1.75 compiler -> rust-native fails in do_compile with poky mickeldore meta-rust/meta-rust#427
  • compiler version can set by adding RUST_VERSION ?= "1.82.0 and require conf/distro/include/rust_versions.inc to local.conf
  • if it turns out that meta-rust is the only viable options, one solution would be to have a recipe that only builds the iceoryx2-ffi-c crate. That recipe would need to carry a patch to remove the workspace references from the Cargo.toml of iceoryx2-ffi-c. In order to not have two sets of recipes, the iceoryx2-c recipe should depend on either iceoryx2-dev or the new package created by the iceoryx2-ffi-c recipe.
• cargo.bbclass
  • https://git.openembedded.org/openembedded-core/tree/meta/classes-recipe/cargo.bbclass
  • https://git.openembedded.org/openembedded-core/tree/meta-selftest/recipes-extended/hello-rs/hello-rs_0.1.0.bb
  • https://git.openembedded.org/openembedded-core/tree/meta-selftest/recipes-extended/hello-rs/hello-rs-crates.inc
  • looks promising
• check if ptest-cargo works with the alternative approach
  • with meta-rust-bin it seems, ptest-cargo invokes meta-rust

[zachary0101]

Just want to provide some information from our project. Hope this is helpful for you!

We don't allow network connection at all for compile task. The reasons are the following:

1. In case it failed to download any crate, it will cause the whole build failed. For nightly build on our build server, it's difficult to re-trigger it in time.
2. Downloading crate will spent extra compiling time.
3. If every developer downloads dependencies by themselves, it will waste network traffic.

Instead, we pre-download all the dependencies to the downloads folder and compress it to a 7z file. Everyone, including the build server, share the same 7z file and decompress it to their workspace. And in our recipes, we use the downloaded crates like this:

SRC_URI += "${CRATE_DEPENDS}"

CRATE_DEPENDS = "
crate://crates.io/addr2line/0.24.2
crate://crates.io/adler2/2.0.0
crate://crates.io/aes/0.8.4
crate://crates.io/ahash/0.8.11
crate://crates.io/aho-corasick/1.1.3
"

SRC_URI[addr2line-0.24.2.sha256sum] = "dfbe277e56a376000877090da837660b4427aad530e3028d44e0bffe4f89a1c1"
SRC_URI[adler2-2.0.0.sha256sum] = "512761e0bb2578dd7380c6baaa0f4ce03e84f95e960231d1dec8bf4d7d6e2627"
SRC_URI[aes-0.8.4.sha256sum] = "b169f7a6d4742236a0a00c541b845991d0ac43e546831af1249753ab4c3aa3a0"
SRC_URI[ahash-0.8.11.sha256sum] = "e89da841a80418a9b391ebaea17f5c112ffaaa96f621d2c285b5174da76b9011"
SRC_URI[aho-corasick-1.1.3.sha256sum] = "8e60d3430d3a69478ad0993f19238d2df97c507009a52b3c10addcd7f6bcb916"

And the rust toolchain we are using now is:
https://git.yoctoproject.org/meta-lts-mixins, scarthgap/rust branch.