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41a20ca0d2
This is in preparation for moving the download-nar procedure out of the script. As well as calling open-connection-for-uri/cached, with-cached-connection adds a single retry to the expression passed in, in the case of a exception that suggests there's a problem with the cached connection. This is important because download-nar/http-fetch doesn't check if a connection used for multiple requests should be closed (because the servers set the relevant response header). To make download-nar more generic, have it take open-connection-for-uri as a keyword argument, and replicate the with-cached-connection single retry by closing the port in the case of a network error, and recalling open-connection-for-uri. This will work fine in the case when connection caching is not in use, as well as when open-connection-for-uri/cached is used, since open-connection-for-uri/cached will open a new connection if the cached port is closed. * guix/scripts/substitute.scm (kind-and-args-exception?): Remove and inline where necessary. (call-with-cached-connection): Remove procedure. (with-cached-connection): Remove syntax rule. (http-response-error?): New procedure. (download-nar): Add new #:open-connection-for-uri keyword argument and use it, also replace with-cached-connection. (process-substitution/fallback,process-substitution): Pass #:open-connection-for-uri open-connection-for-uri/cached to download-nar. Change-Id: I277b1d8dfef79aa1711755b10b9944da7c19157c
-*- mode: org -*- [[https://www.gnu.org/software/guix/][GNU Guix]] (IPA: /ɡiːks/) is a purely functional package manager, and associated free software distribution, for the [[https://www.gnu.org/gnu/gnu.html][GNU system]]. In addition to standard package management features, Guix supports transactional upgrades and roll-backs, unprivileged package management, per-user profiles, and garbage collection. It provides [[https://www.gnu.org/software/guile/][Guile]] Scheme APIs, including a high-level embedded domain-specific languages (EDSLs) to describe how packages are to be built and composed. GNU Guix can be used on top of an already-installed GNU/Linux distribution, or it can be used standalone (we call that “Guix System”). Guix is based on the [[https://nixos.org/nix/][Nix]] package manager. * Requirements If you are building Guix from source, please see the manual for build instructions and requirements, either by running: info -f doc/guix.info "Requirements" or by checking the [[https://guix.gnu.org/manual/en/html_node/Requirements.html][web copy of the manual]]. * Installation See the manual for the installation instructions, either by running info -f doc/guix.info "Installation" or by checking the [[https://guix.gnu.org/manual/en/html_node/Installation.html][web copy of the manual]]. * Building from Git For information on building Guix from a Git checkout, please see the relevant section in the manual, either by running info -f doc/guix.info "Building from Git" or by checking the [[https://guix.gnu.org/manual/en/html_node/Building-from-Git.html][web_copy of the manual]]. * How It Works Guix does the high-level preparation of a /derivation/. A derivation is the promise of a build; it is stored as a text file under =/gnu/store/xxx.drv=. The (guix derivations) module provides the `derivation' primitive, as well as higher-level wrappers such as `build-expression->derivation'. Guix does remote procedure calls (RPCs) to the build daemon (the =guix-daemon= command), which in turn performs builds and accesses to the store on its behalf. The RPCs are implemented in the (guix store) module. * Contact GNU Guix is hosted at https://codeberg.org/guix/guix/. Please email mailto:help-guix@gnu.org for questions. Bug reports should be submitted via https://codeberg.org/guix/guix/issues/. Email mailto:gnu-system-discuss@gnu.org for general issues regarding the GNU system. Join #guix on irc.libera.chat. * Guix & Nix GNU Guix is based on [[https://nixos.org/nix/][the Nix package manager]]. It implements the same package deployment paradigm, and in fact it reuses some of its code. Yet, different engineering decisions were made for Guix, as described below. Nix is really two things: a package build tool, implemented by a library and daemon, and a special-purpose programming language. GNU Guix relies on the former, but uses Scheme as a replacement for the latter. Using Scheme instead of a specific language allows us to get all the features and tooling that come with Guile (compiler, debugger, REPL, Unicode, libraries, etc.) And it means that we have a general-purpose language, on top of which we can have embedded domain-specific languages (EDSLs), such as the one used to define packages. This broadens what can be done in package recipes themselves, and what can be done around them. Technically, Guix makes remote procedure calls to the ‘nix-worker’ daemon to perform operations on the store. At the lowest level, Nix “derivations” represent promises of a build, stored in ‘.drv’ files in the store. Guix produces such derivations, which are then interpreted by the daemon to perform the build. Thus, Guix derivations can use derivations produced by Nix (and vice versa). With Nix and the [[https://nixos.org/nixpkgs][Nixpkgs]] distribution, package composition happens at the Nix language level, but builders are usually written in Bash. Conversely, Guix encourages the use of Scheme for both package composition and builders. Likewise, the core functionality of Nix is written in C++ and Perl; Guix relies on some of the original C++ code, but exposes all the API as Scheme. * Related software - [[https://nixos.org][Nix, Nixpkgs, and NixOS]], functional package manager and associated software distribution, are the inspiration of Guix - [[https://www.gnu.org/software/stow/][GNU Stow]] builds around the idea of one directory per prefix, and a symlink tree to create user environments - [[https://www.pvv.ntnu.no/~arnej/store/storedoc_6.html][STORE]] shares the same idea - [[https://live.gnome.org/OSTree/][GNOME's OSTree]] allows bootable system images to be built from a specified set of packages - The [[https://www.gnu.org/s/gsrc/][GNU Source Release Collection]] (GSRC) is a user-land software distribution; unlike Guix, it relies on core tools available on the host system * Copyright Notices GNU Guix is made available under the GNU GPL version 3 or later license, and authors retain their copyright. For copyright notices, we adhere to the guidance documented in (info "(maintain) Copyright Notices"), and explicitly allow ranges instead of individual years. Here's an example of the preferred style used for copyright notices in source file headers: #+begin_comment Copyright © 2019-2023, 2025 Your Name <your@email.com> #+end_comment Meaning there were copyright-able changes made for the years 2019, 2020, 2021, 2022, 2023 and 2025.