49 lines
1.3 KiB
Markdown
49 lines
1.3 KiB
Markdown
---
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title: "Lets Learn Nix Caching"
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date: 2020-03-17T18:05:38Z
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draft: true
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---
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## TL;DR
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1. I use `NixOS/nixpkgs-channels` instead of `NixOS/nixpkgs` and avoid
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`nix-channel`.
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## More information
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- By default the Nix package manager uses cache.nixos.org as a binary cache.
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- Visit status.nixos.org
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- `git clone git@github.com:NixOS/nixpkgs-channels` instead of
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`NixOS/nixpkgs`. The former mirrors the latter and uses Git branches to track
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the published channels.
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## What is a Nix channel
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If you run...
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```shell
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$ git clone git@github.com:NixOS/nixpkgs ~/nixpkgs
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$ export NIX_PATH="nixpkgs=$(realpath ~/nixpkgs)"
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```
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One benefit to cloning nixpkgs is that you can browse the source code on your
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machine using tools like `git` and `emacs`. You can also experimentally patch
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and test Nix code this way.
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If any of the above appeals to you, clone `nixpkgs-channels` instead.
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The Nix maintainers build and test the commits from `nixpkgs` using Hydra. Tests
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include reproducibility tests, etc.
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Various channels have different verification phases.
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The cache at cache.nixos.org is populate the cache at cache.nixos.org.
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You want to increase the likelihood that you are hitting this cache. For
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example, `google-chrome` takes hours to build.
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## What is a binary cache?
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## What is Hydra (Nix CI)?
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## What is Cachix?
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