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Design sec improvements

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Doron Behar 2020-08-16 15:44:17 +03:00
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rfcs/0075-declarative-wrappers.md
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@ -191,8 +191,8 @@ need feedback regarding whether `gdb` will play nice with this.
This issue may not directly relate to declarative wrappers, and it is already This issue may not directly relate to declarative wrappers, and it is already
addressed in @FRidh's [pull 95569](https://github.com/NixOS/nixpkgs/pull/95569), but perhaps addressed in @FRidh's [pull 95569](https://github.com/NixOS/nixpkgs/pull/95569), but perhaps
both ideas could be integrated into an alternative, simpler creation method of both ideas could be integrated into an alternative, simpler creation method of
binary wrappers. See binary wrappers. See [my
[comment](https://github.com/NixOS/nixpkgs/pull/95569#issuecomment-674508806) comment](https://github.com/NixOS/nixpkgs/pull/95569#issuecomment-674508806).
# Detailed design # Detailed design
[design]: #detailed-design [design]: #detailed-design
@ -200,13 +200,16 @@ binary wrappers. See
The current design is roughly implemented at The current design is roughly implemented at
[pull 85103](https://github.com/NixOS/nixpkgs/pull/85103) . [pull 85103](https://github.com/NixOS/nixpkgs/pull/85103) .
The idea is to have a Nix function, called `wrapGeneric` with an interface The idea is to have a Nix function, let us call it `wrapGeneric`, with an
similar to [`wrapMpv`](https://github.com/NixOS/nixpkgs/blob/a5985162e31587ae04ddc65c4e06146c2aff104c/pkgs/applications/video/mpv/wrapper.nix#L9-L23) and [`wrapNeovim`](https://github.com/NixOS/nixpkgs/blob/a5985162e31587ae04ddc65c4e06146c2aff104c/pkgs/applications/editors/neovim/wrapper.nix#L11-L24) which will accept a single derivation or interface similar to
an array of them and it'll wrap all of their executables with the proper [`wrapMpv`](https://github.com/NixOS/nixpkgs/blob/a5985162e31587ae04ddc65c4e06146c2aff104c/pkgs/applications/video/mpv/wrapper.nix#L9-L23)
environment, based on their inputs. and
[`wrapNeovim`](https://github.com/NixOS/nixpkgs/blob/a5985162e31587ae04ddc65c4e06146c2aff104c/pkgs/applications/editors/neovim/wrapper.nix#L11-L24)
which will accept a single derivation or an array of them and it'll wrap all of
their executables with the proper environment, based on their inputs.
`wrapGeneric` should iterate recursively all `buildInputs` and `wrapGeneric` should iterate recursively all `buildInputs` and
`propagatedBuildInputs` of the input derivations, and construct an attrset with `propagatedBuildInputs` of the input derivation(s), and construct an attrset with
which it'll calculate the necessary environment of the executables. Then either which it'll calculate the necessary environment of the executables. Then either
via `wrapProgram` or a better method, it'll create the wrappers. via `wrapProgram` or a better method, it'll create the wrappers.
@ -218,20 +221,16 @@ and with this information at hand, construct the necessary wrapper.
In order for `wrapGenric` to know all of this information about our packaged In order for `wrapGenric` to know all of this information about our packaged
libraries - the information about runtime env, we need to write in the libraries - the information about runtime env, we need to write in the
`passthru`s of these libraries, what env vars they need. `passthru`s of these libraries, what env vars they need. Such information was
added in the POC pull at [commit
This Nix function, let us call it `wrapGeneric`, should iterate recursively all
`buildInputs` and `propagatedBuildInputs` of a given derivation, and decide
what environment this derivation will need to run. Such information was added
in the [POC pull's
@6283f15](https://github.com/NixOS/nixpkgs/pull/85103/commits/6283f15bb9b65af64571a78b039115807dcc2958). @6283f15](https://github.com/NixOS/nixpkgs/pull/85103/commits/6283f15bb9b65af64571a78b039115807dcc2958).
Additional features / improvements are [already Additional features / improvements are [already
available](https://github.com/NixOS/nixpkgs/pull/85103#issuecomment-614195666) available](https://github.com/NixOS/nixpkgs/pull/85103#issuecomment-614195666)
in the POC pull. For example: in the POC pull. For example:
- It should be impossible for multi-value env vars to have duplicates, as - It should be **impossible** for multi-value env vars to have duplicates, as
that's guaranteed by Nix' behavior when constructing arrays. that's guaranteed by Nix' behavior when constructing arrays / attrsets.
- Asking the wrapper creator to use more links and less colon-separated values - Asking the wrapper creator to use more links and less colon-separated values
in env vars - should help avoid what [pull in env vars - should help avoid what [pull
84689](https://github.com/NixOS/nixpkgs/pull/84689) fixed. 84689](https://github.com/NixOS/nixpkgs/pull/84689) fixed.
@ -242,7 +241,7 @@ in the POC pull. For example:
All examples are copied from and based on the [POC All examples are copied from and based on the [POC
pull](https://github.com/NixOS/nixpkgs/pull/85103). pull](https://github.com/NixOS/nixpkgs/pull/85103).
The new method of creating a python environment: Here's a new method of creating a python environment:
```nix ```nix
my-python-env = wrapGeneric python3 { my-python-env = wrapGeneric python3 {