nvfetcher: Generate nix sources expr for the latest version of packages

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Dependencies aeson (>=1.5.6 && <2.3), aeson-pretty, base (>=4.8 && <5), binary, binary-instances (>=1.0 && <1.1), bytestring, containers, data-default (>=0.7.1 && <0.8), extra (>=1.7 && <1.8), free (>=5.1 && <5.3), microlens, microlens-th, neat-interpolation (>=0.5.1 && <0.6), nvfetcher, optparse-simple (>=0.1.1 && <0.2), parsec, prettyprinter, regex-tdfa (>=1.3.1 && <1.4), shake (>=0.19 && <0.20), text, toml-reader (>=0.2 && <0.3), transformers, unordered-containers, validation-selective [details]
License MIT
Copyright 2021-2023 berberman
Author berberman
Maintainer berberman <berberman.yandex.com>
Revised Revision 1 made by berberman at 2024-01-17T04:06:51Z
Category Nix
Home page https://github.com/berberman/nvfetcher
Bug tracker https://github.com/berberman/nvfetcher/issues
Source repo head: git clone https://github.com/berberman/nvfetcher.git
Uploaded by berberman at 2023-08-18T15:17:23Z
Distributions NixOS:
Executables example, nvfetcher
Downloads 688 total (28 in the last 30 days)
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Status Docs available [build log]
Last success reported on 2023-08-18 [all 1 reports]

Readme for nvfetcher-

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Hackage MIT license nix

nvfetcher is a tool to automate nix package updates. It's built on top of shake, integrating nvchecker. nvfetcher cli program accepts a TOML file as config, which defines a set of package sources to run.


For example, feeding the following configuration tonvfetcher:

# nvfetcher.toml
src.pypi = "feeluown"
fetch.pypi = "feeluown"

it will create _sources/generated.nix:

{ fetchgit, fetchurl, fetchFromGitHub }:
  feeluown = {
    pname = "feeluown";
    version = "3.8.2";
    src = fetchurl {
      url = "https://pypi.io/packages/source/f/feeluown/feeluown-3.8.2.tar.gz";
      sha256 = "sha256-V2yzpkmjRkipZOvQGB2mYRhiiEly6QPrTOMJ7BmyWBQ=";

and _sources/generated.json:

  "feeluown": {
    "pinned": false,
    "cargoLocks": null,
    "name": "feeluown-core",
    "version": "3.8.2",
    "passthru": null,
    "src": {
      "url": "https://pypi.io/packages/source/f/feeluown/feeluown-3.8.2.tar.gz",
      "name": null,
      "type": "url",
      "sha256": "sha256-V2yzpkmjRkipZOvQGB2mYRhiiEly6QPrTOMJ7BmyWBQ="
    "extract": null,
    "rustGitDeps": null

We tell nvfetcher how to get the latest version number of packages and how to fetch their sources given version numbers, and nvfetcher will help us keep their version and prefetched SHA256 sums up-to-date, producing ready-to-use nix expressions in _sources/generated.nix. Nvfetcher reads generated.json to produce version change message, such as feeluown: 3.8.1 → 3.8.2. We always check versions of packages during each run, but only do prefetch and further operations when needed.

Live examples

How to use the generated sources file? Here are several examples:


nvfetcher package is available in nixpkgs, so you can try it with:

$ nix-shell -p nvfetcher

This repo also has flakes support:

$ nix run github:berberman/nvfetcher

To use it as a Haskell library, the package is available on Hackage. If you want to use the Haskell library from flakes, there is also a shell ghcWithNvfetcher:

$ nix develop github:berberman/nvfetcher#ghcWithNvfetcher
$ runghc Main.hs

where you can define packages in Main.hs. See Haskell library for details.


Basically, there are two ways to use nvfetcher, where the difference is how we provide package sources definitions to it.


To run nvfetcher as a CLI program, you'll need to provide package sources defined in TOML.

Usage: nvfetcher [--version] [--help] [-o|--build-dir DIR] [--commit-changes]
                 [-l|--changelog FILE] [-j NUM] [-r|--retry NUM] [-t|--timing]
                 [-v|--verbose] [-f|--filter REGEX] [-k|--keyfile FILE] [TARGET]
                 [-c|--config FILE]
  generate nix sources expr for the latest version of packages

Available options:
  --version                Show version
  --help                   Show this help text
  -o,--build-dir DIR       Directory that nvfetcher puts artifacts to
                           (default: "_sources")
  --commit-changes         `git commit` build dir with version changes as commit
  -l,--changelog FILE      Dump version changes to a file
  -j NUM                   Number of threads (0: detected number of processors)
                           (default: 0)
  -r,--retry NUM           Times to retry of some rules (nvchecker, prefetch,
                           nix-build, etc.) (default: 3)
  -t,--timing              Show build time
  -v,--verbose             Verbose mode
  -f,--filter REGEX        Regex to filter packages to be updated
  -k,--keyfile FILE        Nvchecker keyfile
  TARGET                   Two targets are available: 1.build 2.clean
                           (default: build)
  -c,--config FILE         Path to nvfetcher TOML config
                           (default: "nvfetcher.toml")

Each package corresponds to a TOML table, whose name is encoded as table key, with two required fields and three optional fields in each table. You can find an example of the configuration file, see nvfetcher_example.toml.


You can specify nvchecker keyfile via command line option. For the format of this file, please refer to nvchecker documentation.


Version source -- how do we track upstream version updates?

  • src.github = owner/repo - the latest github release
  • src.github_tag = owner/repo - the max github tag, usually used with list options (see below)
  • src.pypi = pypi_name - the latest pypi release
  • src.git = git_url (and an optional src.branch = git_branch) - the latest commit of a repo
  • src.archpkg = archlinux_pkg_name -- the latest version of an archlinux package
  • src.aur = aur_pkg_name -- the latest version of an aur package
  • src.manual = v -- a fixed version, which never updates
  • src.repology = project:repo -- the latest version from repology
  • src.webpage = web_url and src.regex -- a string in webpage that matches with regex
  • src.httpheader = request_url and src.regex -- a string in http header that matches with regex
  • src.openvsx = publisher.ext_name -- the latest version of a vscode extension from open vsx
  • src.vsmarketplace = publisher.ext_name -- the latest version of a vscode extension from vscode marketplace
  • src.cmd = cmd -- the version from a shell command (e.g. echo Meow)
  • src.container = owner/name - the latest tag of a container from the Docker registry

Optional list options for some version sources (src.github_tag, src.webpage, and src.httpheader and src.container), see the corresponding nvchecker documentation for details.

  • src.include_regex
  • src.exclude_regex
  • src.sort_version_key
  • src.ignored

Optional global options for all kinds of version sources, see the corresponding nvchecker documentation for details. You can tweak obtained version number using this option, e.g. stripping the prefix v or transforming the result by regex.

  • src.prefix
  • src.from_pattern
  • src.to_pattern

Nix fetcher

How do we fetch the package source if we have the target version number? $ver is available in string, which will be set to the result of nvchecker.

  • fetch.github = owner/repo
  • fetch.pypi = pypi_name
  • fetch.git = git_url
  • fetch.url = url
  • fetch.openvsx = publisher.ext_name
  • fetch.vsmarketplace = publisher.ext_name
  • fetch.tarball = tarball_url
  • fetch.docker = owner/name

Optional nix-prefetch fetchgit config, which make sense only when the fetcher equals to fetch.github or fetch.git. They can exist simultaneously.

  • git.deepClone
  • git.fetchSubmodules
  • git.leaveDotGit

Optional config for fetch.docker/dockerTools.pullImage:

  • docker.os
  • docker.arch
  • docker.finalImageName
  • docker.finalImageTag
  • docker.tlsVerify

Extract src

Optional extract src config, files are extracted into build directory, and then read by readFile in generated nix expr.

  • extract = [ "file_1", "file_2", ...] - file paths are relative to the source root

Rust support

rustPlatform.buildRustPackage now accepts an attribute cargoLock to vendor dependencies from Cargo.lock, so we can use this instead of TOFU cargoSha256 for Rust packaging. nvfetcher supports automating this process, extracting the lock file to build and calculating cargoLock.outputHashes, as long as you set the config. There can be many lock files in one source.

  • cargo_locks = [ "cargo_lock_path_1", "cargo_lock_path_2", ...] - relative to the source root


passthru config, an additional set of attrs to be generated.

  • passthru = { k1 = "v1", k2 = "v2", ... }

Note: currently the values can only be strings


If a package is pinned, we call nvchecker to check the new version iff there's no existing version.

  • pinned = true

Git commit date

If the version source of a package is git, nvfetcher can finds out the commit date of this revision, in the format of %Y-%m-%d by default. You can provide your own strftime format:

  • git.date_format = "strftime_format"

Force fetching

Always fetch the package, even if its version (nvchecker output) doesn't change. This is useful when the file to be downloaded cannot not be determined by the url.

  • fetch.force = true

Note: In such case, nvfetcher will not produce a version change log, since the version doesn't change at all. Only sha256 in generated files will be updated.

Haskell library

nvfetcher itself is a Haskell library as well, whereas the CLI program is just a trivial wrapper of the library. You can create a Haskell program depending on it directly, by using the runNvFetcher entry point. In this case, we can define packages in Haskell language, getting rid of TOML constraints.

You can find an example of using nvfetcher in the library way, see Main_example.hs.


For details of the library, documentation of released versions is available on Hackage, and of master is on our github pages.


Issues and PRs are always welcome. _(:з」∠)_

Building from source:

$ git clone https://github.com/berberman/nvfetcher
$ nix develop
$ cabal update
$ cabal build