niv

Painless dependencies for Nix projects. Read more in the Getting started section below.

Install

niv is available in nixpkgs on the master branch as niv. It is also available on the release-19.09 branch as haskellPackages.niv. Otherwise, run:

$ nix-env -iA niv -f https://github.com/nmattia/niv/tarball/master

Build

Inside the provided nix shell:

$ repl

Run the test suite with this command:

$ ./script/test

Usage

niv simplifies adding and updating dependencies in Nix projects. It uses a single file, nix/sources.json, where it stores the data necessary for fetching and updating the packages.

• Add: inserts a package in nix/sources.json.
• Update: updates one or all packages in nix/sources.json.
• Drop: deletes a package from nix/sources.json.

niv has two more utility functions:

• Init: bootstraps a Nix project, in particular creates a nix/sources.json file containing niv and nixpkgs as well as a nix/sources.nix file that returns the sources as a Nix object.
• Show: shows the packages' information.

Configuration

The following environment variables are read by niv:

Name	Note
GITHUB_TOKEN	When set, the value is used to authenticate GitHub API requests.
GITHUB_HOST	The GitHub host to use when fetching packages. Port may be appended here.
GITHUB_API_HOST	The host used when performing GitHub API requests. Use GITHUB_API_PORT for specifying the port.
GITHUB_API_PORT	The port used when performing GitHub API requests. Defaults to 443 for secure requests. Defaults to 80 for insecure requests. See also: GITHUB_INSECURE.
GITHUB_INSECURE	When set to anything but the empty string, requests are performed over http instead of https.
GITHUB_PATH	The base path used when performing GitHub API requests.

The next two sections cover common use cases and full command description.

Getting started

This section covers common use cases:

• Bootstrapping a Nix project.
• Tracking a different nixpkgs branch.
• Importing packages from GitHub.
• Fetching packages from custom URLs.

Bootstrapping a Nix project

Use the init command when starting a new Nix project or when porting an existing Nix project to niv:

$ niv init
...
$ tree
.
└── nix
    ├── sources.json
    └── sources.nix

1 directory, 2 files

The file nix/sources.json is the file used by niv to store versions and is initialized with niv and nixpkgs:

{
    "nixpkgs": {
        "url": "https://github.com/NixOS/nixpkgs-channels/archive/109a28ab954a0ad129f7621d468f829981b8b96c.tar.gz",
        "owner": "NixOS",
        "branch": "nixos-19.09",
        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz",
        "repo": "nixpkgs-channels",
        "sha256": "12wnxla7ld4cgpdndaipdh3j4zdalifk287ihxhnmrzrghjahs3q",
        "description": "Nixpkgs/NixOS branches that track the Nixpkgs/NixOS channels",
        "rev": "109a28ab954a0ad129f7621d468f829981b8b96c"
    },
    "niv": {
        "homepage": "https://github.com/nmattia/niv",
        "url": "https://github.com/nmattia/niv/archive/72e77204544527279e8f1e2d982d29503482b8f4.tar.gz",
        "owner": "nmattia",
        "branch": "master",
        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz",
        "repo": "niv",
        "sha256": "1zjcyzxhq9iwxh58j5d7sx1vz5s3r1f6gpmnfgj2a3rxmclwvn3c",
        "description": "Easy dependency management for Nix projects",
        "rev": "72e77204544527279e8f1e2d982d29503482b8f4"
    }
}

To use those dependencies import the file nix/sources.nix, e.g.:

{ sources ? import ./sources.nix }:     # import the sources
with
  { overlay = _: pkgs:
      { niv = import sources.niv {};    # use the sources :)
      };
  };
import sources.nixpkgs                  # and use them again!
  { overlays = [ overlay ] ; config = {}; }

Tracking a nixpkgs branch

The init command sets the nix/sources.json file to track the latest commit present on nixpkgs 19.09 when the command was run. Run the following command to update it:

$ niv update nixpkgs

To change the branch being tracked run this command:

$ niv update nixpkgs -b nixos-19.09     # equivalent to --branch nixos-19.09

Importing packages from GitHub

The add command will infer information about the package being added, when possible. This works very well for GitHub repositories. Run this command to add jq to your project:

$ niv add stedolan/jq

The following data was added in nix/sources.json for jq:

{
  "homepage": "http://stedolan.github.io/jq/",
  "url": "https://github.com/stedolan/jq/archive/9fa2e51099c55af56e3e541dc4b399f11de74abe.tar.gz",
  "owner": "stedolan",
  "branch": "master",
  "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz",
  "repo": "jq",
  "sha256": "0819rvk8057qgcqvgn7fpldvly2pfdw9fxcjrlqa8gr59p8a1cic",
  "description": "Command-line JSON processor",
  "rev": "9fa2e51099c55af56e3e541dc4b399f11de74abe"
}

Using custom URLs

It is possible to use niv to fetch packages from custom URLs. Run this command to add the Haskell compiler GHC to your nix/sources.json:

$ niv add ghc   \
    -v 8.4.3    \
    -t 'https://downloads.haskell.org/~ghc/<version>/ghc-<version>-i386-deb8-linux.tar.xz'

The option -v sets the "version" attribute to 8.4.3. The option -t sets a template that can be reused by niv when fetching a new URL (see the documentation for add and update).

For updating the version of GHC used run this command:

$ niv update ghc -v 8.6.2

Commands

niv - dependency manager for Nix projects

version: 0.2.12

Usage: niv [-s|--sources-file FILE] COMMAND

Available options:
  -s,--sources-file FILE   Use FILE instead of nix/sources.json
  -h,--help                Show this help text

Available commands:
  init                     Initialize a Nix project. Existing files won't be
                           modified.
  add                      Add a GitHub dependency
  show                     
  update                   Update dependencies
  modify                   Modify dependency
  drop                     Drop dependency

Add

Examples:

  niv add stedolan/jq
  niv add NixOS/nixpkgs-channels -n nixpkgs -b nixos-19.09
  niv add my-package -v alpha-0.1 -t http://example.com/archive/<version>.zip

Usage: niv add PACKAGE [-n|--name NAME] ([-a|--attribute KEY=VAL] |
               [-s|--string-attribute KEY=VAL] | [-b|--branch BRANCH] |
               [-o|--owner OWNER] | [-r|--repo REPO] | [-v|--version VERSION] |
               [-t|--template URL] | [-T|--type TYPE])
  Add a GitHub dependency

Available options:
  -n,--name NAME           Set the package name to <NAME>
  -a,--attribute KEY=VAL   Set the package spec attribute <KEY> to <VAL>, where
                           <VAL> may be JSON.
  -s,--string-attribute KEY=VAL
                           Set the package spec attribute <KEY> to <VAL>.
  -b,--branch BRANCH       Equivalent to --attribute branch=<BRANCH>
  -o,--owner OWNER         Equivalent to --attribute owner=<OWNER>
  -r,--repo REPO           Equivalent to --attribute repo=<REPO>
  -v,--version VERSION     Equivalent to --attribute version=<VERSION>
  -t,--template URL        Used during 'update' when building URL. Occurrences
                           of <foo> are replaced with attribute 'foo'.
  -T,--type TYPE           The type of the URL target. The value can be either
                           'file' or 'tarball'. If not set, the value is
                           inferred from the suffix of the URL.
  -h,--help                Show this help text

Experimental commands:
  git                      Add a git dependency. Experimental.
  github                   Add a GitHub dependency

Update

Examples:
  
  niv update                     # update all packages
  niv update nixpkgs             # update nixpkgs
  niv update my-package -v beta-0.2 # update my-package to version "beta-0.2"

Usage: niv update [PACKAGE] ([-a|--attribute KEY=VAL] |
                  [-s|--string-attribute KEY=VAL] | [-b|--branch BRANCH] |
                  [-o|--owner OWNER] | [-r|--repo REPO] | [-v|--version VERSION]
                  | [-t|--template URL] | [-T|--type TYPE])
  Update dependencies

Available options:
  -a,--attribute KEY=VAL   Set the package spec attribute <KEY> to <VAL>, where
                           <VAL> may be JSON.
  -s,--string-attribute KEY=VAL
                           Set the package spec attribute <KEY> to <VAL>.
  -b,--branch BRANCH       Equivalent to --attribute branch=<BRANCH>
  -o,--owner OWNER         Equivalent to --attribute owner=<OWNER>
  -r,--repo REPO           Equivalent to --attribute repo=<REPO>
  -v,--version VERSION     Equivalent to --attribute version=<VERSION>
  -t,--template URL        Used during 'update' when building URL. Occurrences
                           of <foo> are replaced with attribute 'foo'.
  -T,--type TYPE           The type of the URL target. The value can be either
                           'file' or 'tarball'. If not set, the value is
                           inferred from the suffix of the URL.
  -h,--help                Show this help text

Drop

Examples:

  niv drop jq
  niv drop my-package version

Usage: niv drop PACKAGE [ATTRIBUTE]
  Drop dependency

Available options:
  -h,--help                Show this help text

Init

Usage: niv init 
  Initialize a Nix project. Existing files won't be modified.

Available options:
  -h,--help                Show this help text

show

Usage: niv show [PACKAGE]

Available options:
  -h,--help                Show this help text