nixos: my custom package derivation fails on `cargo build` - rust

Question

I'm writing a package derivation to install kryptco/kr and it fails on cargo build phase.
kryptco/kr has a submodule kryptco/sigchain which is written by rust.
In the Makefile of kryptco/sigchain, they use the cargo web deploy command to build its submodule. My package deriation fails on this cargo web deploy phase.
These two errors were given.
error: warning: replace for the non root package will be ignored, specify replace at the workspace root:
package: /build/src/github.com/kryptco/kr/sigchain/sigchain_client/Cargo.toml
workspace: /build/src/github.com/kryptco/kr/sigchain/Cargo.toml
error: failed to fetch `https://github.com/rust-lang/crates.io-index`
Caused by:
[6] Couldn't resolve host name; class=Net (12)
The former error says to edit Cargo.toml and add [replace] section, but I want to avoid edit source code if I can.
What is the cause of these error?
This is my package derivation:
# Original: https://github.com/bogsen/nixos-public/blob/a0dc497eab5de528ce3006d\
36c52bc601422cf87/pkgs/krypton/default.nix
{ config, lib, pkgs, ... }: with lib; let
cfg = config.services.krypton;
cargoWeb = with pkgs; rustPlatform.buildRustPackage rec {
...
};
dependencies = with pkgs; [
cargo
emscripten
go
makeWrapper
perl
];
kr = pkgs.stdenv.mkDerivation {
name = "kr";
src = pkgs.fetchFromGitHub {
owner = "kryptco";
repo = "kr";
rev = "2.4.10";
sha256 = "1xxhlkcw2d52q1y4h40iyvq25804w7hzv0lflqnib68aps491xnj";
fetchSubmodules = true;
};
buildInputs = dependencies ++ [cargoWeb];
dontBuild = true;
postUnpack = ''
# prevent referring /homeless-shelter
export HOME=$(pwd)
# https://github.com/kryptco/kr/issues/254#issuecomment-464890476
sed -i.bak -e '8,11d' source/sigchain/Cargo.toml
export GOPATH=$(pwd)
export GOCACHE=$GOPATH/.cache/go-build
mkdir -p src/github.com/kryptco
mv source src/github.com/kryptco/kr
ln -s src/github.com/kryptco/kr source
'';
postPatch = ''
substituteInPlace Makefile --replace sudo ""
'';
makeFlags = [ "PREFIX=$(out)" ];
};
in {
config = {
nixpkgs.config.packageOverrides = pkgs: { kr = kr; };
};
}
And whole error message is here.
# use rsync so that file modifed times are only updated when the contents change
cd dashboard_yew && cargo web deploy --release --target=wasm32-unknown-emscripten && rsync --checksum --delete -r ../target/deploy/* ../target/deploy-final
error: warning: replace for the non root package will be ignored, specify replace at the workspace root:
package: /build/src/github.com/kryptco/kr/sigchain/sigchain_client/Cargo.toml
workspace: /build/src/github.com/kryptco/kr/sigchain/Cargo.toml
Updating crates.io index
warning: spurious network error (2 tries remaining): [6] Couldn't resolve host name; class=Net (12)
warning: spurious network error (1 tries remaining): [6] Couldn't resolve host name; class=Net (12)
error: failed to fetch `https://github.com/rust-lang/crates.io-index`
Caused by:
[6] Couldn't resolve host name; class=Net (12)
make[1]: *** [Makefile:25: libsigchain-with-dashboard] Error 101
make[1]: Leaving directory '/build/src/github.com/kryptco/kr/sigchain'
make: *** [Makefile:71: all] Error 2
builder for '/nix/store/78r0kh34ljzgfx658f9n99f8lxydjfxy-kr.drv' failed with exit code 2

Answer 1

I don't think you'll get around the [replace] edit for the config files. The build failing at cargo web deploy is due to an outdated version of openssl-sys (which is discontinued). Here's how Parity fixed it. Looks like they edited the Cargo.lock file to depend on newer versions of this lib.

Answer 2

You need to make it a fixed-output path, for this take a look at nix-pills.