+++ title = "Miscellaneous notes" weight = 20 +++ ## Quirks about cargo2nix/rust in Nix If you use submodules in your crate (like `crdt` and `replication` in `garage_table`), you must list them in `default.nix` The Windows target does not work. it might be solvable through [overrides](https://github.com/cargo2nix/cargo2nix/blob/master/overlay/overrides.nix). Indeed, we pass `x86_64-pc-windows-gnu` but mingw need `x86_64-w64-mingw32` We have a simple [PR on cargo2nix](https://github.com/cargo2nix/cargo2nix/pull/201) that fixes critical bugs but the project does not seem very active currently. We must use [my patched version of cargo2nix](https://github.com/superboum/cargo2nix) to enable i686 and armv6l compilation. We might need to contribute to cargo2nix in the future. ## Nix Nix has no armv7 + musl toolchains but armv7l is backward compatible with armv6l. ```bash cat > $HOME/.awsrc <<EOF export AWS_ACCESS_KEY_ID="xxx" export AWS_SECRET_ACCESS_KEY="xxx" EOF # source each time you want to send on the cache source ~/.awsrc # copy garage build dependencies (and not only the output) nix-build nix-store -qR --include-outputs $(nix-instantiate default.nix) | xargs nix copy --to 's3://nix?endpoint=garage.deuxfleurs.fr®ion=garage' # copy shell dependencies nix-build shell.nix -A inputDerivation nix copy $(nix-store -qR result/) --to 's3://nix?endpoint=garage.deuxfleurs.fr®ion=garage' ``` More example of nix-copy ``` # nix-build produces a result/ symlink nix copy result/ --to 's3://nix?endpoint=garage.deuxfleurs.fr®ion=garage' # alternative ways to use nix copy nix copy nixpkgs.garage --to ... nix copy /nix/store/3rbb9qsc2w6xl5xccz5ncfhy33nzv3dp-crate-garage-0.3.0 --to ... ``` Clear the cache: ```bash mc rm --recursive --force garage/nix/ ``` --- A desirable `nix.conf` for a consumer: ```toml substituters = https://cache.nixos.org https://nix.web.deuxfleurs.fr trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= nix.web.deuxfleurs.fr:eTGL6kvaQn6cDR/F9lDYUIP9nCVR/kkshYfLDJf1yKs= ``` And now, whenever you run a command like: ``` nix-shell nix-build ``` Our cache will be checked. ### Some references about Nix - https://doc.rust-lang.org/nightly/rustc/platform-support.html - https://nix.dev/tutorials/cross-compilation - https://nixos.org/manual/nix/unstable/package-management/s3-substituter.html - https://fzakaria.com/2020/09/28/nix-copy-closure-your-nix-shell.html - http://www.lpenz.org/articles/nixchannel/index.html ## Woodpecker Woodpecker can do parallelism both at the step and the pipeline level. At the step level, parallelism is restricted to the same runner. ## Building Docker containers We were: - Unable to use the official Docker plugin because - it requires to mount docker socket in the container but it is not recommended - you cant set the platform when building - Unable to use buildah because it needs `CLONE_USERNS` capability - Unable to use the kaniko plugin for Drone as we can't set the target platform - Unable to use the kaniko container provided by Google as we can't run arbitrary logic: we need to put our secret in .docker/config.json. Finally we chose to build kaniko through nix and use it in a `nix-shell`. We then switched to using kaniko from nixpkgs when it was packaged.