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Remove unecessary non-fileset part

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Silvan Mosberger 2023-11-22 21:47:35 +01:00
parent 69e6dd6d9d
commit 9ecfd01a0d
1 changed files with 5 additions and 73 deletions
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78
source/tutorials/file-sets.md
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@ -106,7 +106,6 @@ $ cd fileset
$ nix-shell -p niv --run "niv init --nixpkgs nixos/nixpkgs --nixpkgs-branch master"
```
Then create a `default.nix` file with the following contents:
```{code-block} nix
@ -132,79 +131,12 @@ $ echo hello > hello.txt
$ echo world > world.txt
```
Start with a minimal `build.nix` based on [`stdenv.mkDerivation`](https://nixos.org/manual/nixpkgs/stable/#part-stdenv):
```{code-block} nix
:caption: build.nix
{ stdenv }:
stdenv.mkDerivation {
name = "fileset";
# This doesn't use the file set library just yet!
src = ./.;
postInstall = ''
mkdir $out
cp -v hello.txt $out
'';
}
```
Try it out (note that it will take some time to fetch the first time around):
```shell-session
$ nix-build
this derivation will be built:
/nix/store/36p7xhc0rr8jvslban0zba0f7aij8cmb-fileset.drv
building '/nix/store/36p7xhc0rr8jvslban0zba0f7aij8cmb-fileset.drv'...
...
'hello.txt' -> '/nix/store/zdljz7v5bhv1nnh5mdh3xf418cf7z622-fileset/hello.txt'
...
/nix/store/zdljz7v5bhv1nnh5mdh3xf418cf7z622-fileset
```
Since only `hello.txt` is needed to build the derivation,
we can try passing it directly in `src`.
But this will result in an error, because `mkDerivation` expects a directory:
```{code-block} diff
:caption: build.nix
{ stdenv }:
stdenv.mkDerivation {
name = "fileset";
# This doesn't use the file set library just yet!
- src = ./.;
+ src = ./hello.txt;
postInstall = ''
mkdir $out
cp -v hello.txt $out
'';
}
```
```shell-session
$ nix-build
this derivation will be built:
/nix/store/kaik07l2i7s7wh7lcxpwynv4lmn4h742-fileset.drv
building '/nix/store/kaik07l2i7s7wh7lcxpwynv4lmn4h742-fileset.drv'...
unpacking sources
unpacking source archive /nix/store/i9pmrzmpshapij2kin22pff6fc2adavx-hello.txt
do not know how to unpack source archive /nix/store/i9pmrzmpshapij2kin22pff6fc2adavx-
hello.txt
error: builder for '/nix/store/kaik07l2i7s7wh7lcxpwynv4lmn4h742-fileset.drv' failed w
ith exit code 1;
last 3 log lines:
> unpacking sources
> unpacking source archive /nix/store/i9pmrzmpshapij2kin22pff6fc2adavx-hello.t
xt
> do not know how to unpack source archive /nix/store/i9pmrzmpshapij2kin22pff6
fc2adavx-hello.txt
For full logs, run 'nix log /nix/store/kaik07l2i7s7wh7lcxpwynv4lmn4h742-filese
t.drv'.
```
## Adding files to the Nix store
That's where [`toSource`](https://nixos.org/manual/nixpkgs/unstable/#function-library-lib.fileset.toSource) comes in:
It adds exactly the files in the given file set to a directory in the Nix store, starting from a specified root path.
To add files in a given file set to the Nix store,
we use [`toSource`](https://nixos.org/manual/nixpkgs/unstable/#function-library-lib.fileset.toSource).
This function needs a `root` attribute to know which path to use as the root of the resulting store path,
but only exactly the files in the `fileset` argument are included in the result.
Define `build.nix` as follows:
@ -233,7 +165,7 @@ stdenv.mkDerivation {
The call to `fs.trace` prints the file set that will be used as a derivation input.
The build will succeed:
The build will succeed (note that it will take some time to fetch the first time around):
```
$ nix-build