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doc: update buildNixShellImage docs, add streamNixShellImage docs

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doc/build-helpers/images/dockertools.section.md
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@ -1282,141 +1282,288 @@ dockerTools.buildLayeredImage {
```
:::
[]{#ssec-pkgs-dockerTools-buildNixShellImage-arguments}
## buildNixShellImage {#ssec-pkgs-dockerTools-buildNixShellImage}
Create a Docker image that sets up an environment similar to that of running `nix-shell` on a derivation.
When run in Docker, this environment somewhat resembles the Nix sandbox typically used by `nix-build`, with a major difference being that access to the internet is allowed.
It additionally also behaves like an interactive `nix-shell`, running things like `shellHook` and setting an interactive prompt.
If the derivation is fully buildable (i.e. `nix-build` can be used on it), running `buildDerivation` inside such a Docker image will build the derivation, with all its outputs being available in the correct `/nix/store` paths, pointed to by the respective environment variables like `$out`, etc.
`buildNixShellImage` uses [`streamNixShellImage`](#ssec-pkgs-dockerTools-streamNixShellImage) underneath to build a compressed Docker-compatible repository tarball of an image that sets up an environment similar to that of running `nix-shell` on a derivation.
Basically, `buildNixShellImage` runs the script created by `streamNixShellImage` to save the compressed image in the Nix store.
::: {.warning}
The behavior doesn't match `nix-shell` or `nix-build` exactly and this function is known not to work correctly for e.g. fixed-output derivations, content-addressed derivations, impure derivations and other special types of derivations.
:::
`buildNixShellImage` supports the same options as `streamNixShellImage`, see [`streamNixShellImage`](#ssec-pkgs-dockerTools-streamNixShellImage) for details.
### Arguments {#ssec-pkgs-dockerTools-buildNixShellImage-arguments}
[]{#ssec-pkgs-dockerTools-buildNixShellImage-example}
### Examples {#ssec-pkgs-dockerTools-buildNixShellImage-examples}
`drv`
:::{.example #ex-dockerTools-buildNixShellImage-hello}
# Building a Docker image with `buildNixShellImage` with the build environment for the `hello` package
: The derivation on which to base the Docker image.
Adding packages to the Docker image is possible by e.g. extending the list of `nativeBuildInputs` of this derivation like
```nix
buildNixShellImage {
drv = someDrv.overrideAttrs (old: {
nativeBuildInputs = old.nativeBuildInputs or [] ++ [
somethingExtra
];
});
# ...
}
```
Similarly, you can extend the image initialization script by extending `shellHook`
`name` _optional_
: The name of the resulting image.
*Default:* `drv.name + "-env"`
`tag` _optional_
: Tag of the generated image.
*Default:* the resulting image derivation output path's hash
`uid`/`gid` _optional_
: The user/group ID to run the container as. This is like a `nixbld` build user.
*Default:* 1000/1000
`homeDirectory` _optional_
: The home directory of the user the container is running as
*Default:* `/build`
`shell` _optional_
: The path to the `bash` binary to use as the shell. This shell is started when running the image.
*Default:* `pkgs.bashInteractive + "/bin/bash"`
`command` _optional_
: Run this command in the environment of the derivation, in an interactive shell. See the `--command` option in the [`nix-shell` documentation](https://nixos.org/manual/nix/stable/command-ref/nix-shell.html?highlight=nix-shell#options).
*Default:* (none)
`run` _optional_
: Same as `command`, but runs the command in a non-interactive shell instead. See the `--run` option in the [`nix-shell` documentation](https://nixos.org/manual/nix/stable/command-ref/nix-shell.html?highlight=nix-shell#options).
*Default:* (none)
### Example {#ssec-pkgs-dockerTools-buildNixShellImage-example}
The following shows how to build the `pkgs.hello` package inside a Docker container built with `buildNixShellImage`.
This example shows how to build the `hello` package inside a Docker container built with `buildNixShellImage`.
The Docker image generated will have a name like `hello-<version>-env` and tag `latest`.
This example is the `buildNixShellImage` equivalent of [](#ex-dockerTools-streamNixShellImage-hello).
```nix
with import <nixpkgs> {};
{ dockerTools, hello }:
dockerTools.buildNixShellImage {
drv = hello;
tag = "latest";
}
```
Build the derivation:
The result of building this package is a `.tar.gz` file that can be loaded into Docker:
```console
nix-build hello.nix
```shell
$ nix-build
(some output removed for clarity)
/nix/store/pkj1sgzaz31wl0pbvbg3yp5b3kxndqms-hello-2.12.1-env.tar.gz
$ docker load -i /nix/store/pkj1sgzaz31wl0pbvbg3yp5b3kxndqms-hello-2.12.1-env.tar.gz
(some output removed for clarity)
Loaded image: hello-2.12.1-env:latest
```
these 8 derivations will be built:
/nix/store/xmw3a5ln29rdalavcxk1w3m4zb2n7kk6-nix-shell-rc.drv
...
Creating layer 56 from paths: ['/nix/store/crpnj8ssz0va2q0p5ibv9i6k6n52gcya-stdenv-linux']
Creating layer 57 with customisation...
Adding manifests...
Done.
/nix/store/cpyn1lc897ghx0rhr2xy49jvyn52bazv-hello-2.12-env.tar.gz
After starting an interactive container, the derivation can be built by running `buildDerivation`, and the output can be executed as expected:
Load the image:
```shell
$ docker run -it hello-2.12.1-env:latest
[nix-shell:~]$ buildDerivation
Running phase: unpackPhase
unpacking source archive /nix/store/pa10z4ngm0g83kx9mssrqzz30s84vq7k-hello-2.12.1.tar.gz
source root is hello-2.12.1
(some output removed for clarity)
Running phase: fixupPhase
shrinking RPATHs of ELF executables and libraries in /nix/store/f2vs29jibd7lwxyj35r9h87h6brgdysz-hello-2.12.1
shrinking /nix/store/f2vs29jibd7lwxyj35r9h87h6brgdysz-hello-2.12.1/bin/hello
checking for references to /build/ in /nix/store/f2vs29jibd7lwxyj35r9h87h6brgdysz-hello-2.12.1...
gzipping man pages under /nix/store/f2vs29jibd7lwxyj35r9h87h6brgdysz-hello-2.12.1/share/man/
patching script interpreter paths in /nix/store/f2vs29jibd7lwxyj35r9h87h6brgdysz-hello-2.12.1
stripping (with command strip and flags -S -p) in /nix/store/f2vs29jibd7lwxyj35r9h87h6brgdysz-hello-2.12.1/bin
```console
docker load -i result
[nix-shell:~]$ $out/bin/hello
Hello, world!
```
:::
## streamNixShellImage {#ssec-pkgs-dockerTools-streamNixShellImage}
`streamNixShellImage` builds a **script** which, when run, will stream to stdout a Docker-compatible repository tarball of an image that sets up an environment similar to that of running `nix-shell` on a derivation.
This means that `streamNixShellImage` does not output an image into the Nix store, but only a script that builds the image, saving on IO and disk/cache space, particularly with large images.
See [](#ex-dockerTools-streamNixShellImage-hello) to understand how to load in Docker the image generated by this script.
The environment set up by `streamNixShellImage` somewhat resembles the Nix sandbox typically used by `nix-build`, with a major difference being that access to the internet is allowed.
It also behaves like an interactive `nix-shell`, running things like `shellHook` (see [](#ex-dockerTools-streamNixShellImage-addingShellHook)) and setting an interactive prompt.
If the derivation is buildable (i.e. `nix-build` can be used on it), running `buildDerivation` in the container will build the derivation, with all its outputs being available in the correct `/nix/store` paths, pointed to by the respective environment variables (e.g. `$out`).
::: {.caution}
The environment in the image doesn't match `nix-shell` or `nix-build` exactly, and this function is known not to work correctly for fixed-output derivations, content-addressed derivations, impure derivations and other special types of derivations.
:::
### Inputs {#ssec-pkgs-dockerTools-streamNixShellImage-inputs}
`streamNixShellImage` expects one argument with the following attributes:
`drv` (Attribute Set)
: The derivation for which the environment in the image will be set up.
Adding packages to the Docker image is possible by extending the list of `nativeBuildInputs` of this derivation.
See [](#ex-dockerTools-streamNixShellImage-extendingBuildInputs) for how to do that.
Similarly, you can extend the image initialization script by extending `shellHook`.
[](#ex-dockerTools-streamNixShellImage-addingShellHook) shows how to do that.
`name` (String; _optional_)
: The name of the generated image.
_Default value:_ the value of `drv.name + "-env"`.
`tag` (String or Null; _optional_)
: Tag of the generated image.
If `null`, the hash of the nix derivation that builds the Docker image will be used as the tag.
_Default value:_ `null`.
`uid` (Number; _optional_)
: The user ID to run the container as.
This can be seen as a `nixbld` build user.
_Default value:_ 1000.
`gid` (Number; _optional_)
: The group ID to run the container as.
This can be seen as a `nixbld` build group.
_Default value:_ 1000.
`homeDirectory` (String; _optional_)
: The home directory of the user the container is running as.
_Default value:_ `/build`.
`shell` (String; _optional_)
: The path to the `bash` binary to use as the shell.
This shell is started when running the image.
This can be seen as an equivalent of the `NIX_BUILD_SHELL` [environment variable](https://nixos.org/manual/nix/stable/command-ref/nix-shell.html#environment-variables) for {manpage}`nix-shell(1)`.
_Default value:_ the `bash` binary from the `bashInteractive` package.
`command` (String or Null; _optional_)
: If specified, this command will be run in the environment of the derivation in an interactive shell.
A call to `exit` will be added after the command if it is specified, so the shell will exit after it's finished running.
This can be seen as an equivalent of the `--command` option in {manpage}`nix-shell(1)`.
_Default value:_ `null`.
`run` (String or Null; _optional_)
: Similar to the `command` attribute, but runs the command in a non-interactive shell instead.
A call to `exit` will be added after the command if it is specified, so the shell will exit after it's finished running.
This can be seen as an equivalent of the `--run` option in {manpage}`nix-shell(1)`.
_Default value:_ `null`.
### Examples {#ssec-pkgs-dockerTools-streamNixShellImage-examples}
:::{.example #ex-dockerTools-streamNixShellImage-hello}
# Building a Docker image with `streamNixShellImage` with the build environment for the `hello` package
This example shows how to build the `hello` package inside a Docker container built with `streamNixShellImage`.
The Docker image generated will have a name like `hello-<version>-env` and tag `latest`.
This example is the `streamNixShellImage` equivalent of [](#ex-dockerTools-buildNixShellImage-hello).
```nix
{ dockerTools, hello }:
dockerTools.streamNixShellImage {
drv = hello;
tag = "latest";
}
```
0d9f4c4cd109: Loading layer [==================================================>] 2.56MB/2.56MB
...
ab1d897c0697: Loading layer [==================================================>] 10.24kB/10.24kB
Loaded image: hello-2.12-env:pgj9h98nal555415faa43vsydg161bdz
The result of building this package is a script.
Running this script and piping it into `docker load` gives you the same image that was built in [](#ex-dockerTools-buildNixShellImage-hello).
Run the container:
```shell
$ nix-build
(some output removed for clarity)
/nix/store/8vhznpz2frqazxnd8pgdvf38jscdypax-stream-hello-2.12.1-env
```console
docker run -it hello-2.12-env:pgj9h98nal555415faa43vsydg161bdz
$ /nix/store/8vhznpz2frqazxnd8pgdvf38jscdypax-stream-hello-2.12.1-env | docker load
(some output removed for clarity)
Loaded image: hello-2.12.1-env:latest
```
[nix-shell:/build]$
After starting an interactive container, the derivation can be built by running `buildDerivation`, and the output can be executed as expected:
In the running container, run the build:
```shell
$ docker run -it hello-2.12.1-env:latest
[nix-shell:~]$ buildDerivation
Running phase: unpackPhase
unpacking source archive /nix/store/pa10z4ngm0g83kx9mssrqzz30s84vq7k-hello-2.12.1.tar.gz
source root is hello-2.12.1
(some output removed for clarity)
Running phase: fixupPhase
shrinking RPATHs of ELF executables and libraries in /nix/store/f2vs29jibd7lwxyj35r9h87h6brgdysz-hello-2.12.1
shrinking /nix/store/f2vs29jibd7lwxyj35r9h87h6brgdysz-hello-2.12.1/bin/hello
checking for references to /build/ in /nix/store/f2vs29jibd7lwxyj35r9h87h6brgdysz-hello-2.12.1...
gzipping man pages under /nix/store/f2vs29jibd7lwxyj35r9h87h6brgdysz-hello-2.12.1/share/man/
patching script interpreter paths in /nix/store/f2vs29jibd7lwxyj35r9h87h6brgdysz-hello-2.12.1
stripping (with command strip and flags -S -p) in /nix/store/f2vs29jibd7lwxyj35r9h87h6brgdysz-hello-2.12.1/bin
```console
buildDerivation
[nix-shell:~]$ $out/bin/hello
Hello, world!
```
:::
:::{.example #ex-dockerTools-streamNixShellImage-extendingBuildInputs}
# Adding extra packages to a Docker image built with `streamNixShellImage`
This example shows how to add extra packages to an image built with `streamNixShellImage`.
In this case, we'll add the `cowsay` package.
The Docker image generated will have a name like `hello-<version>-env` and tag `latest`.
This example uses [](#ex-dockerTools-streamNixShellImage-hello) as a starting point.
```nix
{ dockerTools, cowsay, hello }:
dockerTools.streamNixShellImage {
tag = "latest";
drv = hello.overrideAttrs (old: {
nativeBuildInputs = old.nativeBuildInputs or [] ++ [
cowsay
];
});
}
```
unpacking sources
unpacking source archive /nix/store/8nqv6kshb3vs5q5bs2k600xpj5bkavkc-hello-2.12.tar.gz
...
patching script interpreter paths in /nix/store/z5wwy5nagzy15gag42vv61c2agdpz2f2-hello-2.12
checking for references to /build/ in /nix/store/z5wwy5nagzy15gag42vv61c2agdpz2f2-hello-2.12...
The result of building this package is a script which can be run and piped into `docker load` to load the generated image.
Check the build result:
```shell
$ nix-build
(some output removed for clarity)
/nix/store/h5abh0vljgzg381lna922gqknx6yc0v7-stream-hello-2.12.1-env
```console
$out/bin/hello
$ /nix/store/h5abh0vljgzg381lna922gqknx6yc0v7-stream-hello-2.12.1-env | docker load
(some output removed for clarity)
Loaded image: hello-2.12.1-env:latest
```
Hello, world!
After starting an interactive container, we can verify the extra package is available by running `cowsay`:
```shell
$ docker run -it hello-2.12.1-env:latest
[nix-shell:~]$ cowsay "Hello, world!"
_______________
< Hello, world! >
---------------
\ ^__^
\ (oo)\_______
(__)\ )\/\
||----w |
|| ||
```
:::
:::{.example #ex-dockerTools-streamNixShellImage-addingShellHook}
# Adding a `shellHook` to a Docker image built with `streamNixShellImage`
This example shows how to add a `shellHook` command to an image built with `streamNixShellImage`.
In this case, we'll simply output the string `Hello, world!`.
The Docker image generated will have a name like `hello-<version>-env` and tag `latest`.
This example uses [](#ex-dockerTools-streamNixShellImage-hello) as a starting point.
```nix
{ dockerTools, hello }:
dockerTools.streamNixShellImage {
tag = "latest";
drv = hello.overrideAttrs (old: {
shellHook = ''
${old.shellHook or ""}
echo "Hello, world!"
'';
});
}
```
The result of building this package is a script which can be run and piped into `docker load` to load the generated image.
```shell
$ nix-build
(some output removed for clarity)
/nix/store/iz4dhdvgzazl5vrgyz719iwjzjy6xlx1-stream-hello-2.12.1-env
$ /nix/store/iz4dhdvgzazl5vrgyz719iwjzjy6xlx1-stream-hello-2.12.1-env | docker load
(some output removed for clarity)
Loaded image: hello-2.12.1-env:latest
```
After starting an interactive container, we can see the result of the `shellHook`:
```shell
$ docker run -it hello-2.12.1-env:latest
Hello, world!
[nix-shell:~]$
```
:::

3
doc/manpage-urls.json
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@ -317,5 +317,6 @@
"udevadm(8)": "https://www.freedesktop.org/software/systemd/man/udevadm.html",
"passwd(5)": "https://man.archlinux.org/man/passwd.5",
"group(5)": "https://man.archlinux.org/man/group.5",
"login.defs(5)": "https://man.archlinux.org/man/login.defs.5"
"login.defs(5)": "https://man.archlinux.org/man/login.defs.5",
"nix-shell(1)": "https://nixos.org/manual/nix/stable/command-ref/nix-shell.html"
}