237 lines
4.6 KiB
Markdown
237 lines
4.6 KiB
Markdown
---
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marp: true
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lang: en-US
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title: Reproducible development environments with Nix
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theme: nix_talk
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transition: fade
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paginate: true
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_paginate: false
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---
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# Reproducible development environments with Nix
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#### Kateřina "Kate" Churanová
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---
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# What is Nix
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- Purely functional programming language
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- Package manager
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- multiplatform (Linux, Mac OS, BSD-ish)
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---
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# What is Nix NOT
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- Easy to learn
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- Well documented
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- Opinionated
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---
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# What is it for
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- Access to huge repository of various packages
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- Declarative way to define builds and build enviroment and their configuration
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- Coexistence of various versions of software and libraries on the same system
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*Every simple configuration language will eventually end up being turing complete*
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---
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# Nix derivation
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- "Package"
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- evaluates to store derivation in `/nix/store/`
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- `2n45ikclc8d5fhzkvg1197qlc2zk3s64-rustc-1.77.2.drv`
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<!-- This prevents conflicts and allows various versions to be installed at ones. -->
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---
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# Nix flake
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- Unstable, but widely used
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- New way of creating nix derivations
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- Lock file version pinning
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- Allows reproducibility
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---
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```nix
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{
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inputs = {
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nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
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};
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outputs =
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{ self, nixpkgs }:
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{
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packages.x86_64-linux.default = nixpkgs.legacyPackages.x86_64-linux.hello;
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packages.x86_64-linux.foobar = nixpkgs.legacyPackages.x86_64-linux.fortune;
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};
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}
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```
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---
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---
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# Nix developer shell
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- `nix develop`
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- builds all flake dependencies, but not the flake itself
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- sets up the development environment
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---
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# Nix direnv
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- https://github.com/nix-community/nix-direnv
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- Activates developer shell automatically
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---
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# Frameworks
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- Pure nix solution is usable, but tedious with ugly boilerplate
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- [Numtide: flake-utils](https://github.com/ursi/numtide-flake-utils)
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- [Hercules CI: Flake Parts](https://flake.parts/)
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<!-- Both are fairly lightweight and remove boilerplate. -->
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---
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# Flake parts - Minimal modular framework
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## Dev environment management
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- Devshell
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- Devenv
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## Rust project building
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- NCI (Nix cargo integration)
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---
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# Basic flake parts project
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```nix
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{
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inputs = {
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flake-parts.url = "github:hercules-ci/flake-parts";
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nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
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};
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outputs = inputs@{ flake-parts, ... }:
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flake-parts.lib.mkFlake { inherit inputs; } {
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imports = [
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# Modules go here
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];
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systems = [ "x86_64-linux" "aarch64-linux" "aarch64-darwin" "x86_64-darwin" ];
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perSystem = { config, self', inputs', pkgs, system, ... }: {
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packages.default = pkgs.hello;
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};
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};
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}
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```
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---
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# Fun begins with Rust
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### flake.nix
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```nix
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inputs = {
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nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
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nci = {
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url = "github:yusdacra/nix-cargo-integration";
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inputs.nixpkgs.follows = "nixpkgs";
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};
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flake-parts = {
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url = "github:hercules-ci/flake-parts";
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inputs.nixpkgs-lib.follows = "nixpkgs";
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};
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};
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```
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---
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```nix
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outputs = inputs @ {
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flake-parts,
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nci,
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...
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}:
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flake-parts.lib.mkFlake {inherit inputs;} {
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systems = ["x86_64-linux"];
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imports = [
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nci.flakeModule
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./crates.nix
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];
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perSystem = {
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pkgs,
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config,
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...
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}: let
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crateName = "my-crate"
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crateOutputs = config.nci.outputs.${crateName};
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in {
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devShells.default = crateOutputs.devShell;
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packages.default = crateOutputs.packages.release;
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};
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};
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```
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---
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### crates.nix
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```nix
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{...}: {
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perSystem = {
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pkgs,
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config,
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...
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}: let
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crateName = "my-crate";
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in {
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nci.projects."simple".path = ./.;
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nci.crates.${crateName} = {};
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};
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}
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```
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---
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# Why all of this though?
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- Reproducible environment with pinned Rust version
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- Predictable dependencies
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- Plenty of other tools for your disposal
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- Extremely simple generation of lightweight OCI containers
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---
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```nix
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packages.container = pkgs.dockerTools.streamLayeredImage {
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name = crateName;
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tag = "latest";
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contents = [ ];
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config = {
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Cmd = [ "${crateOutputs.packages.release}/bin/my-crate" ];
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};
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};
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```
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---
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# Other learning materials
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### Fasterthanlime's series on Rust development with Nix
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[https://fasterthanli.me/series/building-a-rust-service-with-nix](https://fasterthanli.me/series/building-a-rust-service-with-nix)
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### Nix pills
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[https://nixos.org/guides/nix-pills/](https://nixos.org/guides/nix-pills/)
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### This presentation and examples
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[https://code.nolog.cz/shine/nix_for_rustaceans](https://code.nolog.cz/shine/nix_for_rustaceans)
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