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https://github.com/tweag/rules_nixpkgs

Rules for importing Nixpkgs packages into Bazel.
https://github.com/tweag/rules_nixpkgs

bazel bazel-rules nix nixpkgs

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Rules for importing Nixpkgs packages into Bazel.

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README 

        



# Nixpkgs rules for Bazel



[![Continuous integration](https://github.com/tweag/rules_nixpkgs/actions/workflows/workflow.yaml/badge.svg?event=schedule)](https://github.com/tweag/rules_nixpkgs/actions/workflows/workflow.yaml)



Use [Nix][nix] and the [Nixpkgs][nixpkgs] package set to import

external dependencies (like system packages) into [Bazel][bazel]

hermetically. If the version of any dependency changes, Bazel will

correctly rebuild targets, and only those targets that use the

external dependencies that changed.



Links:

* [Nix + Bazel = fully reproducible, incremental

  builds][blog-bazel-nix] (blog post)

* [Nix + Bazel][youtube-bazel-nix] (lightning talk)



[nix]: https://nixos.org/nix

[nixpkgs]: https://github.com/NixOS/nixpkgs

[bazel]: https://bazel.build

[blog-bazel-nix]: https://www.tweag.io/posts/2018-03-15-bazel-nix.html

[youtube-bazel-nix]: https://www.youtube.com/watch?v=7-K_RmDasEg&t=2030s



See [examples](/examples/toolchains) for how to use `rules_nixpkgs` with different toolchains.



## Rules



* [nixpkgs_git_repository](#nixpkgs_git_repository)

* [nixpkgs_http_repository](#nixpkgs_http_repository)

* [nixpkgs_local_repository](#nixpkgs_local_repository)

* [nixpkgs_package](#nixpkgs_package)

* [nixpkgs_flake_package](#nixpkgs_flake_package)

* [nixpkgs_cc_configure](#nixpkgs_cc_configure)

* [nixpkgs_cc_configure_deprecated](#nixpkgs_cc_configure_deprecated)

* [nixpkgs_java_configure](#nixpkgs_java_configure)

* [nixpkgs_python_configure](#nixpkgs_python_configure)

* [nixpkgs_python_repository](#nixpkgs_python_repository)

* [nixpkgs_go_configure](toolchains/go/README.md#nixpkgs_go_configure)

* [nixpkgs_rust_configure](#nixpkgs_rust_configure)

* [nixpkgs_sh_posix_configure](#nixpkgs_sh_posix_configure)

* [nixpkgs_nodejs_configure](#nixpkgs_nodejs_configure)



## Setup



Add the following to your `WORKSPACE` file, and select a `$COMMIT` accordingly.



```bzl

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")



http_archive(

    name = "io_tweag_rules_nixpkgs",

    strip_prefix = "rules_nixpkgs-$COMMIT",

    urls = ["https://github.com/tweag/rules_nixpkgs/archive/$COMMIT.tar.gz"],

)



load("@io_tweag_rules_nixpkgs//nixpkgs:repositories.bzl", "rules_nixpkgs_dependencies")

rules_nixpkgs_dependencies()



load("@io_tweag_rules_nixpkgs//nixpkgs:nixpkgs.bzl", "nixpkgs_git_repository", "nixpkgs_package", "nixpkgs_cc_configure")



load("@io_tweag_rules_nixpkgs//nixpkgs:toolchains/go.bzl", "nixpkgs_go_configure") # optional

```



If you use `rules_nixpkgs` to configure a toolchain, then you will also need to

configure the build platform to include the

`@rules_nixpkgs_core//constraints:support_nix` constraint. For

example by adding the following to `.bazelrc`:



```

build --host_platform=@rules_nixpkgs_core//platforms:host

```



## Example



```bzl

nixpkgs_git_repository(

    name = "nixpkgs",

    revision = "17.09", # Any tag or commit hash

    sha256 = "" # optional sha to verify package integrity!

)



nixpkgs_package(

    name = "hello",

    repositories = { "nixpkgs": "@nixpkgs//:default.nix" }

)

```



## Migration from older releases



### `path` Attribute (removed in 0.3)



`path` was an attribute from the early days of `rules_nixpkgs`, and

its ability to reference arbitrary paths is a danger to build hermeticity.



Replace it with either `nixpkgs_git_repository` if you need

a specific version of `nixpkgs`. If you absolutely *must* depend on a

local folder, use Bazel's

[`local_repository` workspace rule](https://docs.bazel.build/versions/master/be/workspace.html#local_repository).

Both approaches work well with the `repositories` attribute of `nixpkgs_package`.



```bzl

local_repository(

  name = "local-nixpkgs",

  path = "/path/to/nixpkgs",

)



nixpkgs_package(

  name = "somepackage",

  repositories = {

    "nixpkgs": "@local-nixpkgs//:default.nix",

  },

)

```



# Reference documentation






### nixpkgs_cc_configure




nixpkgs_cc_configure(name, attribute_path, nix_file, nix_file_content, nix_file_deps, repositories,

                     repository, nixopts, quiet, fail_not_supported, exec_constraints,

                     target_constraints, register, cc_lang, cc_std, cross_cpu)




Use a CC toolchain from Nixpkgs. No-op if not a nix-based platform.



By default, Bazel auto-configures a CC toolchain from commands (e.g.

`gcc`) available in the environment. To make builds more hermetic, use

this rule to specify explicitly which commands the toolchain should use.



Specifically, it builds a Nix derivation that provides the CC toolchain

tools in the `bin/` path and constructs a CC toolchain that uses those

tools. Tools that aren't found are replaced by `${coreutils}/bin/false`.

You can inspect the resulting `@_info//:CC_TOOLCHAIN_INFO` to see

which tools were discovered.



If you specify the `nix_file` or `nix_file_content` argument, the CC

toolchain is discovered by evaluating the corresponding expression. In

addition, you may use the `attribute_path` argument to select an attribute

from the result of the expression to use as the CC toolchain (see example below).



If neither the `nix_file` nor `nix_file_content` argument is used, the

toolchain is discovered from the `stdenv.cc` and the `stdenv.cc.bintools`

attributes of the given `` repository.



```

# use GCC 11

nixpkgs_cc_configure(

  repository = "@nixpkgs",

  nix_file_content = "(import  {}).gcc11",

)

```

```

# use GCC 11 (same result as above)

nixpkgs_cc_configure(

  repository = "@nixpkgs",

  attribute_path = "gcc11",

  nix_file_content = "import  {}",

)

```

```

# alternate usage without specifying `nix_file` or `nix_file_content`

nixpkgs_cc_configure(

  repository = "@nixpkgs",

  attribute_path = "gcc11",

)

```

```

# use the `stdenv.cc` compiler (the default of the given @nixpkgs repository)

nixpkgs_cc_configure(

  repository = "@nixpkgs",

)

```



This rule depends on [`rules_cc`](https://github.com/bazelbuild/rules_cc).



**Note:**

You need to configure `--crosstool_top=@//:toolchain` to activate

this toolchain.



#### Parameters



name



optional.

default is "local_config_cc"



attribute_path



optional.

default is ""






optional, string, Obtain the toolchain from the Nix expression under this attribute path. Uses default repository if no `nix_file` or `nix_file_content` is provided.






nix_file



optional.

default is None






optional, Label, Obtain the toolchain from the Nix expression defined in this file. Specify only one of `nix_file` or `nix_file_content`.






nix_file_content



optional.

default is ""






optional, string, Obtain the toolchain from the given Nix expression. Specify only one of `nix_file` or `nix_file_content`.






nix_file_deps



optional.

default is []






optional, list of Label, Additional files that the Nix expression depends on.






repositories



optional.

default is {}






dict of Label to string, Provides `` and other repositories. Specify one of `repositories` or `repository`.






repository



optional.

default is None






Label, Provides ``. Specify one of `repositories` or `repository`.






nixopts



optional.

default is []






optional, list of string, Extra flags to pass when calling Nix. See `nixopts` attribute to `nixpkgs_package` for further details.






quiet



optional.

default is False






bool, Whether to hide `nix-build` output.






fail_not_supported



optional.

default is True






bool, Whether to fail if `nix-build` is not available.






exec_constraints



optional.

default is None






Constraints for the execution platform.






target_constraints



optional.

default is None






Constraints for the target platform.






register



optional.

default is True






bool, enabled by default, Whether to register (with `register_toolchains`) the generated toolchain and install it as the default cc_toolchain.






cc_lang



optional.

default is "c++"






string, `"c++"` by default. Used to populate `CXX_FLAG` so the compiler is called in C++ mode. Can be set to `"none"` together with appropriate `copts` in the `cc_library` call: see above.






cc_std



optional.

default is "c++0x"






string, `"c++0x"` by default. Used to populate `CXX_FLAG` so the compiler uses the given language standard. Can be set to `"none"` together with appropriate `copts` in the `cc_library` call: see above.






cross_cpu



optional.

default is ""






string, `""` by default. Used if you want to add a cross compilation C/C++ toolchain. Set this to the CPU architecture for the target CPU. For example x86_64, would be k8.









### nixpkgs_cc_configure_deprecated




nixpkgs_cc_configure_deprecated(repository, repositories, nix_file, nix_file_deps, nix_file_content,

                                nixopts)




Use a CC toolchain from Nixpkgs. No-op if not a nix-based platform.



Tells Bazel to use compilers and linkers from Nixpkgs for the CC toolchain.

By default, Bazel auto-configures a CC toolchain from commands available in

the environment (e.g. `gcc`). Overriding this autodetection makes builds

more hermetic and is considered a best practice.



#### Example



  ```bzl

  nixpkgs_cc_configure(repository = "@nixpkgs//:default.nix")

  ```



#### Parameters



repository



optional.

default is None






A repository label identifying which Nixpkgs to use.

Equivalent to `repositories = { "nixpkgs": ...}`.






repositories



optional.

default is {}






A dictionary mapping `NIX_PATH` entries to repository labels.



Setting it to

```

repositories = { "myrepo" : "//:myrepo" }

```

for example would replace all instances of `` in the called nix code by the path to the target `"//:myrepo"`. See the [relevant section in the nix manual](https://nixos.org/nix/manual/#env-NIX_PATH) for more information.



Specify one of `repository` or `repositories`.






nix_file



optional.

default is None






An expression for a Nix environment derivation.

The environment should expose all the commands that make up a CC

toolchain (`cc`, `ld` etc). Exposes all commands in `stdenv.cc` and

`binutils` by default.






nix_file_deps



optional.

default is None






Dependencies of `nix_file` if any.






nix_file_content



optional.

default is None






An expression for a Nix environment derivation.






nixopts



optional.

default is []






Options to forward to the nix command.









### nixpkgs_flake_package




nixpkgs_flake_package(name, nix_flake_file, nix_flake_lock_file, nix_flake_file_deps, package,

                      build_file, build_file_content, nixopts, quiet, fail_not_supported,

                      legacy_path_syntax, kwargs)




Make the content of a local Nix Flake package available in the Bazel workspace.



**IMPORTANT NOTE**: Calling `nix build` copies the entirety of the Nix Flake

into the Nix Store.  When using the `path:` syntax, this means the directory

containing `flake.nix` and any subdirectories.  Without specifying `path:`

Nix may infer that the flake is the Git repository and copy the entire thing.

As a consequence, you may want to isolate your flake from the rest of the

repository to minimize the amount of unnecessary data that gets copied into

the Nix Store whenever the flake is rebuilt.



#### Parameters



name



required.






A unique name for this repository.






nix_flake_file



required.






Label to `flake.nix` that will be evaluated.






nix_flake_lock_file



required.






Label to `flake.lock` that corresponds to `nix_flake_file`.






nix_flake_file_deps



optional.

default is []






Additional dependencies of `nix_flake_file` if any.






package



optional.

default is None






Nix Flake package to make available.  The default package will be used if not specified.






build_file



optional.

default is None






The file to use as the BUILD file for this repository. See [`nixpkgs_package`](#nixpkgs_package-build_file) for more information.






build_file_content



optional.

default is ""






Like `build_file`, but a string of the contents instead of a file name. See [`nixpkgs_package`](#nixpkgs_package-build_file_content) for more information.






nixopts



optional.

default is []






Extra flags to pass when calling Nix. See [`nixpkgs_package`](#nixpkgs_package-nixopts) for more information.






quiet



optional.

default is False






Whether to hide the output of the Nix command.






fail_not_supported



optional.

default is True






If set to `True` (default) this rule will fail on platforms which do not support Nix (e.g. Windows). If set to `False` calling this rule will succeed but no output will be generated.






legacy_path_syntax



optional.

default is False






If set to True (not default), the Nix Flake invocation will directly call `nix build ` instead of `nix build path:` which may involve copying the entirety of the Git repo into the Nix Store instead of just the path and its children.






kwargs



optional.






Common rule arguments.









### nixpkgs_git_repository




nixpkgs_git_repository(name, revision, remote, sha256, kwargs)




Name a specific revision of Nixpkgs on GitHub or a local checkout.



#### Parameters



name



required.






String



A unique name for this repository.






revision



required.






String



Git commit hash or tag identifying the version of Nixpkgs to use.






remote



optional.

default is "https://github.com/NixOS/nixpkgs"






String



The URI of the remote Git repository. This must be a HTTP URL. There is

currently no support for authentication. Defaults to [upstream

nixpkgs](https://github.com/NixOS/nixpkgs).






sha256



optional.

default is None






String



The SHA256 used to verify the integrity of the repository.






kwargs



optional.






Additional arguments to forward to the underlying repository rule.









### nixpkgs_http_repository




nixpkgs_http_repository(name, url, urls, auth, strip_prefix, integrity, sha256, kwargs)




Download a Nixpkgs repository over HTTP.



#### Parameters



name



required.






String



A unique name for this repository.






url



optional.

default is None






String



A URL to download the repository from.



This must be a file, http or https URL. Redirections are followed.



More flexibility can be achieved by the urls parameter that allows

to specify alternative URLs to fetch from.






urls



optional.

default is None






List of String



A list of URLs to download the repository from.



Each entry must be a file, http or https URL. Redirections are followed.



URLs are tried in order until one succeeds, so you should list local mirrors first.

If all downloads fail, the rule will fail.






auth



optional.

default is None






Dict of String



An optional dict mapping host names to custom authorization patterns.



If a URL's host name is present in this dict the value will be used as a pattern when

generating the authorization header for the http request. This enables the use of custom

authorization schemes used in a lot of common cloud storage providers.



The pattern currently supports 2 tokens: <login> and

<password>, which are replaced with their equivalent value

in the netrc file for the same host name. After formatting, the result is set

as the value for the Authorization field of the HTTP request.



Example attribute and netrc for a http download to an oauth2 enabled API using a bearer token:




auth_patterns = {

    "storage.cloudprovider.com": "Bearer <password>"

}




netrc:




machine storage.cloudprovider.com

        password RANDOM-TOKEN




The final HTTP request would have the following header:




Authorization: Bearer RANDOM-TOKEN




strip_prefix



optional.

default is None






String



A directory prefix to strip from the extracted files.



Many archives contain a top-level directory that contains all of the useful

files in archive. This field can be used to strip it from all of the

extracted files.



For example, suppose you are using `nixpkgs-22.11.zip`, which contains

the directory `nixpkgs-22.11/` under which there is the `default.nix`

file and the `pkgs/` directory. Specify `strip_prefix =

"nixpkgs-22.11"` to use the `nixpkgs-22.11` directory as your top-level

directory.



Note that if there are files outside of this directory, they will be

discarded and inaccessible (e.g., a top-level license file). This includes

files/directories that start with the prefix but are not in the directory

(e.g., `nixpkgs-22.11.release-notes`). If the specified prefix does not

match a directory in the archive, Bazel will return an error.






integrity



optional.

default is None






String



Expected checksum in Subresource Integrity format of the file downloaded.



This must match the checksum of the file downloaded. _It is a security risk

to omit the checksum as remote files can change._ At best omitting this

field will make your build non-hermetic. It is optional to make development

easier but either this attribute or `sha256` should be set before shipping.






sha256



optional.

default is None






String

The expected SHA-256 of the file downloaded.



This must match the SHA-256 of the file downloaded. _It is a security risk

to omit the SHA-256 as remote files can change._ At best omitting this

field will make your build non-hermetic. It is optional to make development

easier but should be set before shipping.






kwargs



optional.






Additional arguments to forward to the underlying repository rule.









### nixpkgs_java_configure




nixpkgs_java_configure(name, attribute_path, java_home_path, repository, repositories, nix_file,

                       nix_file_content, nix_file_deps, nixopts, fail_not_supported, quiet, toolchain,

                       register, toolchain_name, toolchain_version, exec_constraints,

                       target_constraints)




Define a Java runtime provided by nixpkgs.



Creates a `nixpkgs_package` for a `java_runtime` instance. Optionally,

you can also create & register a Java toolchain. This only works with Bazel >= 5.0

Bazel can use this instance to run JVM binaries and tests, refer to the

[Bazel documentation](https://docs.bazel.build/versions/4.0.0/bazel-and-java.html#configuring-the-jdk) for details.



#### Example



##### Bazel 4



Add the following to your `WORKSPACE` file to import a JDK from nixpkgs:

```bzl

load("@io_tweag_rules_nixpkgs//nixpkgs:nixpkgs.bzl", "nixpkgs_java_configure")

nixpkgs_java_configure(

    attribute_path = "jdk11.home",

    repository = "@nixpkgs",

)

```



Add the following configuration to `.bazelrc` to enable this Java runtime:

```

build --javabase=@nixpkgs_java_runtime//:runtime

build --host_javabase=@nixpkgs_java_runtime//:runtime

# Adjust this to match the Java version provided by this runtime.

# See `bazel query 'kind(java_toolchain, @bazel_tools//tools/jdk:all)'` for available options.

build --java_toolchain=@bazel_tools//tools/jdk:toolchain_java11

build --host_java_toolchain=@bazel_tools//tools/jdk:toolchain_java11

```



##### Bazel 5



Add the following to your `WORKSPACE` file to import a JDK from nixpkgs:

```bzl

load("@io_tweag_rules_nixpkgs//nixpkgs:nixpkgs.bzl", "nixpkgs_java_configure")

nixpkgs_java_configure(

    attribute_path = "jdk11.home",

    repository = "@nixpkgs",

    toolchain = True,

    toolchain_name = "nixpkgs_java",

    toolchain_version = "11",

)

```



Add the following configuration to `.bazelrc` to enable this Java runtime:

```

build --host_platform=@io_tweag_rules_nixpkgs//nixpkgs/platforms:host

build --java_runtime_version=nixpkgs_java

build --tool_java_runtime_version=nixpkgs_java

```



##### Bazel 6



Add the following to your `WORKSPACE` file to import a JDK from nixpkgs:

```bzl

load("@io_tweag_rules_nixpkgs//nixpkgs:nixpkgs.bzl", "nixpkgs_java_configure")

nixpkgs_java_configure(

    attribute_path = "jdk11.home",

    repository = "@nixpkgs",

    toolchain = True,

    toolchain_name = "nixpkgs_java",

    toolchain_version = "11",

)

```



Add the following configuration to `.bazelrc` to enable this Java runtime:

```

build --host_platform=@io_tweag_rules_nixpkgs//nixpkgs/platforms:host

build --java_runtime_version=nixpkgs_java_11

build --tool_java_runtime_version=nixpkgs_java_11

build --java_language_version=11

build --tool_java_language_version=11

```



#### Parameters



name



optional.

default is "nixpkgs_java_runtime"






The name-prefix for the created external repositories.






attribute_path



optional.

default is None






string, The nixpkgs attribute path for `jdk.home`.






java_home_path



optional.

default is ""






optional, string, The path to `JAVA_HOME` within the package.






repository



optional.

default is None






See [`nixpkgs_package`](#nixpkgs_package-repository).






repositories



optional.

default is {}






See [`nixpkgs_package`](#nixpkgs_package-repositories).






nix_file



optional.

default is None






optional, Label, Obtain the runtime from the Nix expression defined in this file. Specify only one of `nix_file` or `nix_file_content`.






nix_file_content



optional.

default is ""






optional, string, Obtain the runtime from the given Nix expression. Specify only one of `nix_file` or `nix_file_content`.






nix_file_deps



optional.

default is None






See [`nixpkgs_package`](#nixpkgs_package-nix_file_deps).






nixopts



optional.

default is []






See [`nixpkgs_package`](#nixpkgs_package-nixopts).






fail_not_supported



optional.

default is True






See [`nixpkgs_package`](#nixpkgs_package-fail_not_supported).






quiet



optional.

default is False






See [`nixpkgs_package`](#nixpkgs_package-quiet).






toolchain



optional.

default is False






Create a Bazel toolchain based on the Java runtime.






register



optional.

default is None






Register the created toolchain. Requires `toolchain` to be `True`. Defaults to the value of `toolchain`.






toolchain_name



optional.

default is None






The name of the toolchain that can be used in --java_runtime_version.






toolchain_version



optional.

default is None






The version of the toolchain that can be used in --java_runtime_version.






exec_constraints



optional.

default is None






Constraints for the execution platform.






target_constraints



optional.

default is None






Constraints for the target platform.









### nixpkgs_local_repository




nixpkgs_local_repository(name, nix_file, nix_file_deps, nix_file_content, nix_flake_lock_file,

                         kwargs)




Create an external repository representing the content of Nixpkgs.



Based on a Nix expression stored locally or provided inline. One of

`nix_file` or `nix_file_content` must be provided.



#### Parameters



name



required.






String



A unique name for this repository.






nix_file



optional.

default is None






Label



A file containing an expression for a Nix derivation.






nix_file_deps



optional.

default is None






List of labels



Dependencies of `nix_file` if any.






nix_file_content



optional.

default is None






String



An expression for a Nix derivation.






nix_flake_lock_file



optional.

default is None






String



A flake lock file that can be used on the provided nixpkgs repository.






kwargs



optional.






Additional arguments to forward to the underlying repository rule.









### nixpkgs_nodejs_configure




nixpkgs_nodejs_configure(name, attribute_path, repository, repositories, nix_platform, nix_file,

                         nix_file_content, nix_file_deps, nixopts, fail_not_supported, quiet,

                         exec_constraints, target_constraints, register)




#### Parameters



name



optional.

default is "nixpkgs_nodejs"



attribute_path



optional.

default is "nodejs"



repository



optional.

default is None



repositories



optional.

default is {}



nix_platform



optional.

default is None



nix_file



optional.

default is None



nix_file_content



optional.

default is None



nix_file_deps



optional.

default is None



nixopts



optional.

default is []



fail_not_supported



optional.

default is True



quiet



optional.

default is False



exec_constraints



optional.

default is None



target_constraints



optional.

default is None



register



optional.

default is True






### nixpkgs_nodejs_configure_platforms




nixpkgs_nodejs_configure_platforms(name, platforms_mapping, attribute_path, repository,

                                   repositories, nix_platform, nix_file, nix_file_content,

                                   nix_file_deps, nixopts, fail_not_supported, quiet,

                                   exec_constraints, target_constraints, register, kwargs)




Runs nixpkgs_nodejs_configure for each platform.



Since rules_nodejs adds platform suffix to repository name, this can be helpful

if one wants to use npm_install and reference js dependencies from npm repo.

See the example directory.



#### Parameters



name



optional.

default is "nixpkgs_nodejs"



platforms_mapping



optional.

default is {"aarch64-darwin": struct(exec_constraints = ["@platforms//os:macos", "@platforms//cpu:arm64"], rules_nodejs_platform = "darwin_arm64", target_constraints = ["@platforms//os:macos", "@platforms//cpu:arm64"]), "x86_64-linux": struct(exec_constraints = ["@platforms//os:linux", "@platforms//cpu:x86_64"], rules_nodejs_platform = "linux_amd64", target_constraints = ["@platforms//os:linux", "@platforms//cpu:x86_64"]), "x86_64-darwin": struct(exec_constraints = ["@platforms//os:macos", "@platforms//cpu:x86_64"], rules_nodejs_platform = "darwin_amd64", target_constraints = ["@platforms//os:macos", "@platforms//cpu:x86_64"]), "aarch64-linux": struct(exec_constraints = ["@platforms//os:linux", "@platforms//cpu:arm64"], rules_nodejs_platform = "linux_arm64", target_constraints = ["@platforms//os:linux", "@platforms//cpu:arm64"])}






struct describing mapping between nix platform and rules_nodejs bazel platform with

target and exec constraints






attribute_path



optional.

default is "nodejs"



repository



optional.

default is None



repositories



optional.

default is {}



nix_platform



optional.

default is None



nix_file



optional.

default is None



nix_file_content



optional.

default is None



nix_file_deps



optional.

default is None



nixopts



optional.

default is []



fail_not_supported



optional.

default is True



quiet



optional.

default is False



exec_constraints



optional.

default is None



target_constraints



optional.

default is None



register



optional.

default is True



kwargs



optional.






### nixpkgs_package




nixpkgs_package(name, attribute_path, nix_file, nix_file_deps, nix_file_content, repository,

                repositories, build_file, build_file_content, nixopts, quiet, fail_not_supported,

                kwargs)




Make the content of a Nixpkgs package available in the Bazel workspace.



If `repositories` is not specified, you must provide a nixpkgs clone in `nix_file` or `nix_file_content`.



#### Parameters



name



required.






A unique name for this repository.






attribute_path



optional.

default is ""






Select an attribute from the top-level Nix expression being evaluated. The attribute path is a sequence of attribute names separated by dots.






nix_file



optional.

default is None






A file containing an expression for a Nix derivation.






nix_file_deps



optional.

default is []






Dependencies of `nix_file` if any.






nix_file_content



optional.

default is ""






An expression for a Nix derivation.






repository



optional.

default is None






A repository label identifying which Nixpkgs to use. Equivalent to `repositories = { "nixpkgs": ...}`






repositories



optional.

default is {}






A dictionary mapping `NIX_PATH` entries to repository labels.



Setting it to

```

repositories = { "myrepo" : "//:myrepo" }

```

for example would replace all instances of `` in the called nix code by the path to the target `"//:myrepo"`. See the [relevant section in the nix manual](https://nixos.org/nix/manual/#env-NIX_PATH) for more information.



Specify one of `repository` or `repositories`.






build_file



optional.

default is None






The file to use as the BUILD file for this repository.



Its contents are copied into the file `BUILD` in root of the nix output folder. The Label does not need to be named `BUILD`, but can be.



For common use cases we provide filegroups that expose certain files as targets:





  
:bin


  
Everything in the bin/ directory.


  
:lib


  
All .so, .dylib and .a files that can be found in subdirectories of lib/.


  
:include


  
All .h, .hh, .hpp and .hxx files that can be found in subdirectories of include/.





If you need different files from the nix package, you can reference them like this:

```

package(default_visibility = [ "//visibility:public" ])

filegroup(

    name = "our-docs",

    srcs = glob(["share/doc/ourpackage/**/*"]),

)

```

See the bazel documentation of [`filegroup`](https://docs.bazel.build/versions/master/be/general.html#filegroup) and [`glob`](https://docs.bazel.build/versions/master/be/functions.html#glob).



build_file_content



optional.

default is ""






Like `build_file`, but a string of the contents instead of a file name.






nixopts



optional.

default is []






Extra flags to pass when calling Nix.



Subject to location expansion, any instance of `$(location LABEL)` will be replaced by the path to the file referenced by `LABEL` relative to the workspace root.



Note, labels to external workspaces will resolve to paths that contain `~` characters if the Bazel flag `--enable_bzlmod` is true. Nix does not support `~` characters in path literals at the time of writing, see [#7742](https://github.com/NixOS/nix/issues/7742). Meaning, the result of location expansion may not form a valid Nix path literal. Use `./$${"$(location @for//:example)"}` to work around this limitation if you need to pass a path argument via `--arg`, or pass the resulting path as a string value using `--argstr` and combine it with an additional `--arg workspace_root ./.` argument using `workspace_root + ("/" + path_str)`.






quiet



optional.

default is False






Whether to hide the output of the Nix command.






fail_not_supported



optional.

default is True






If set to `True` (default) this rule will fail on platforms which do not support Nix (e.g. Windows). If set to `False` calling this rule will succeed but no output will be generated.






kwargs



optional.






### nixpkgs_python_configure




nixpkgs_python_configure(name, python3_attribute_path, python3_bin_path, repository, repositories,

                         nix_file_deps, nixopts, fail_not_supported, quiet, exec_constraints,

                         target_constraints, register)




Define and register a Python toolchain provided by nixpkgs.



Creates `nixpkgs_package`s for Python 2 or 3 `py_runtime` instances and a

corresponding `py_runtime_pair` and `toolchain`. The toolchain is

automatically registered and uses the constraint:



```

"@io_tweag_rules_nixpkgs//nixpkgs/constraints:support_nix"

```



#### Parameters



name



optional.

default is "nixpkgs_python_toolchain"






The name-prefix for the created external repositories.






python3_attribute_path



optional.

default is "python3"






The nixpkgs attribute path for python3.






python3_bin_path



optional.

default is "bin/python"






The path to the interpreter within the package.






repository



optional.

default is None






See [`nixpkgs_package`](#nixpkgs_package-repository).






repositories



optional.

default is {}






See [`nixpkgs_package`](#nixpkgs_package-repositories).






nix_file_deps



optional.

default is None






See [`nixpkgs_package`](#nixpkgs_package-nix_file_deps).






nixopts



optional.

default is []






See [`nixpkgs_package`](#nixpkgs_package-nixopts).






fail_not_supported



optional.

default is True






See [`nixpkgs_package`](#nixpkgs_package-fail_not_supported).






quiet



optional.

default is False






See [`nixpkgs_package`](#nixpkgs_package-quiet).






exec_constraints



optional.

default is None






Constraints for the execution platform.






target_constraints



optional.

default is None






Constraints for the target platform.






register



optional.

default is True






### nixpkgs_python_repository




nixpkgs_python_repository(name, repository, repositories, nix_file, nix_file_deps, quiet)




Define a collection of python packages based on a nix file.



The only entry point is a [`nix_file`](#nixpkgs_python_repository-nix_file)

which should expose a `pkgs` and a `python` attributes. `python` is the

python interpreter, and `pkgs` a set of python packages that will be made

available to bazel.



:warning: All the packages in `pkgs` are built by this rule. It is

therefore not a good idea to expose something as big as `pkgs.python3` as

provided by nixpkgs.



This rule is instead intended to expose an ad-hoc set of packages for your

project, as can be built by poetry2nix, mach-nix, dream2nix or by manually

picking the python packages you need from nixpkgs.



The format is generic to support the many ways to generate such packages

sets with nixpkgs. See our python [`tests`](/testing/toolchains/python) and

[`examples`](/examples/toolchains/python) to get started.



This rule is intended to mimic as closely as possible the [rules_python

API](https://github.com/bazelbuild/rules_python#using-the-package-installation-rules).

`nixpkgs_python_repository` should be a drop-in replacement of `pip_parse`.

As such, it also provides a `requirement` function.



:warning: Using the `requirement` fucntion inherits the same advantages and

limitations as the one in rules_python. All the function does is create a

label of the form `@{nixpkgs_python_repository_name}//:{package_name}`.

While depending on such a label directly will work, the layout may change

in the future. To be on the safe side, define and import your own

`requirement` function if you need to play with these labels.



:warning: Just as with rules_python, nothing is done to enforce consistency

between the version of python used to generate this repository and the one

configured in your toolchain, even if you use nixpkgs_python_toolchain. You

should ensure they both use the same python from the same nixpkgs version.



:warning: packages names exposed by this rule are determined by the `pname`

attribute of the corresponding nix package. These may vary slightly from

names used by rules_python. Should this be a problem, you can provide you

own `requirement` function, for example one that lowercases its argument.



#### Parameters



name



required.






The name for the created package set.






repository



optional.

default is None






See [`nixpkgs_package`](#nixpkgs_package-repository).






repositories



optional.

default is {}






See [`nixpkgs_package`](#nixpkgs_package-repositories).






nix_file



optional.

default is None






See [`nixpkgs_package`](#nixpkgs_package-nix_file).






nix_file_deps



optional.

default is []






See [`nixpkgs_package`](#nixpkgs_package-nix_file_deps).






quiet



optional.

default is False






See [`nixpkgs_package`](#nixpkgs_package-quiet).









### nixpkgs_rust_configure




nixpkgs_rust_configure(name, default_edition, repository, repositories, nix_file, nix_file_deps,

                       nix_file_content, nixopts, fail_not_supported, quiet, exec_constraints,

                       target_constraints, register)




#### Parameters



name



optional.

default is "nixpkgs_rust"



default_edition



optional.

default is "2018"



repository



optional.

default is None



repositories



optional.

default is {}



nix_file



optional.

default is None



nix_file_deps



optional.

default is None



nix_file_content



optional.

default is None



nixopts



optional.

default is []



fail_not_supported



optional.

default is True



quiet



optional.

default is False



exec_constraints



optional.

default is None



target_constraints



optional.

default is None



register



optional.

default is True






### nixpkgs_sh_posix_configure




nixpkgs_sh_posix_configure(name, packages, exec_constraints, register, kwargs)




Create a POSIX toolchain from nixpkgs.



Loads the given Nix packages, scans them for standard Unix tools, and

generates a corresponding `sh_posix_toolchain`.



Make sure to call `nixpkgs_sh_posix_configure` before `sh_posix_configure`,

if you use both. Otherwise, the local toolchain will always be chosen in

favor of the nixpkgs one.



#### Parameters



name



optional.

default is "nixpkgs_sh_posix_config"






Name prefix for the generated repositories.






packages



optional.

default is ["stdenv.initialPath"]






List of Nix attribute paths to draw Unix tools from.






exec_constraints



optional.

default is None






Constraints for the execution platform.






register



optional.

default is True






Automatically register the generated toolchain if set to True.






kwargs



optional.