STATUS: unstable
The goal of this project is to simplify per-project developer environments.
Imagine, a new employee joins the company, or somebody transfers teams, or somebody wants to contribute to one of your Open Source projects. It should take them 10 minutes to clone the repo and get all of the development dependencies.
See docs
Keep it compatible with:
- nix-shell
- direnv
- nix flakes
pkgs.stdenv.mkDerivation and pkgs.mkShell build on top of the
pkgs.stdenv which introduces all sort of dependencies. Each added package,
like the pkgs.go in the "Story time!" section has the potential of adding
new environment variables, which then need to be unset. The stdenv itself
contains either GCC or Clang which makes it hard to select a specific C
compiler.
This is why mkDevShell builds its environment from a builtins.derivation.
direnv loads will change from:
direnv: export +AR +AS +CC +CONFIG_SHELL +CXX +HOST_PATH +IN_NIX_SHELL +LD +NIX_BINTOOLS +NIX_BINTOOLS_WRAPPER_TARGET_HOST_x86_64_unknown_linux_gnu +NIX_BUILD_CORES +NIX_BUILD_TOP +NIX_CC +NIX_CC_WRAPPER_TARGET_HOST_x86_64_unknown_linux_gnu +NIX_CFLAGS_COMPILE +NIX_ENFORCE_NO_NATIVE +NIX_HARDENING_ENABLE +NIX_INDENT_MAKE +NIX_LDFLAGS +NIX_STORE +NM +OBJCOPY +OBJDUMP +RANLIB +READELF +RUSTC +SIZE +SOURCE_DATE_EPOCH +STRINGS +STRIP +TEMP +TEMPDIR +TMP +TMPDIR +buildInputs +buildPhase +builder +builtDependencies +cargo_bins_jq_filter +cargo_build_options +cargo_options +cargo_release +cargo_test_options +cargoconfig +checkPhase +configureFlags +configurePhase +cratePaths +crate_sources +depsBuildBuild +depsBuildBuildPropagated +depsBuildTarget +depsBuildTargetPropagated +depsHostHost +depsHostHostPropagated +depsTargetTarget +depsTargetTargetPropagated +doCheck +doInstallCheck +docPhase +dontAddDisableDepTrack +dontUseCmakeConfigure +installPhase +name +nativeBuildInputs +out +outputs +patches +preInstallPhases +propagatedBuildInputs +propagatedNativeBuildInputs +remapPathPrefix +shell +src +stdenv +strictDeps +system +version ~PATH
to:
direnv: export +DEVSHELL_DIR +DEVSHELL_ROOT +IN_NIX_SHELL +NIXPKGS_PATH ~PATH
There are new environment variables useful to support the day-to-day activities:
DEVSHELL_DIR: contains all the programs.DEVSHELL_ROOT: points to the project root.NIXPKGS_PATH: path tonixpkgssource.
The shell comes pre-loaded with some utility functions. I'm not 100% sure if those are useful yet:
devshell-menu- list all the programs availabledevshell-root-cdback to the project root.
When entering a random project, it's useful to get a quick view of what commands are available.
When running nix-shell or nix develop, mkDevShell prints a welcome
message:
### 🔨 Welcome to mkDevShell ####
# Commands
devshell-menu - print this menu
devshell-root - change directory to root
hello - prints hello
nixpkgs-fmt - used to format Nix code
You might be passionate about Nix, but people on the team might be afraid of that non-mainstream technology. So let them write TOML instead. It should handle 80% of the use-cases and falling back on Nix is always possible.
Life is not complete otherwise. Huhu.
Packages that contain bash completions will automatically be loaded by
mkDevShell in nix-shell or nix develop modes.
With a CI + Binary cache setup, one often wants to be able to capture all the
build inputs of a shell.nix. Before, pkgs.mkShell would even refuse to
build! (my fault really). With pkgs.mkDevShell, capturing all of the
development dependencies is as easy as:
nix-build shell.nix | cachix push <mycache>A lot of things!
Explain how all of this works and all the use-cases.
Write integration tests for all of the use-cases.
This requires some coordination with the repository structure. To keep the dev closure small, it would be nice to be able to load some of the dependencies on demand.
Not everything can be nicely sandboxed. Is it possible to get a fast doctor script that checks that everything is in good shape?
What? Not everyone is using bash? Right now, support is already available in direnv mode.