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1 | | -#################################### |
2 | | -# Environment setup for Nix shells # |
3 | | -#################################### |
4 | | - |
5 | | -# From https://github.com/direnv/direnv/wiki/Nix#persistent-cached-shell |
6 | | -# |
7 | | -# Usage: use_nix [...] |
8 | | -# |
9 | | -# Load environment variables from `nix-shell`. |
10 | | -# If you have a `default.nix` or `shell.nix` one of these will be used and |
11 | | -# the derived environment will be stored at ./.direnv/env-<hash> |
12 | | -# and symlink to it will be created at ./.direnv/default. |
13 | | -# Dependencies are added to the GC roots, such that the environment remains persistent. |
14 | | -# |
15 | | -# Packages can also be specified directly via e.g `use nix -p ocaml`, |
16 | | -# however those will not be added to the GC roots. |
17 | | -# |
18 | | -# The resulting environment is cached for better performance. |
19 | | -# |
20 | | -# To trigger switch to a different environment: |
21 | | -# `rm -f .direnv/default` |
22 | | -# |
23 | | -# To derive a new environment: |
24 | | -# `rm -rf .direnv/env-$(md5sum {shell,default}.nix 2> /dev/null | cut -c -32)` |
25 | | -# |
26 | | -# To remove cache: |
27 | | -# `rm -f .direnv/dump-*` |
28 | | -# |
29 | | -# To remove all environments: |
30 | | -# `rm -rf .direnv/env-*` |
31 | | -# |
32 | | -# To remove only old environments: |
33 | | -# `find .direnv -name 'env-*' -and -not -name `readlink .direnv/default` -exec rm -rf {} +` |
34 | | -# |
35 | | -use_nix() { |
36 | | - set -e |
37 | | - |
38 | | - local shell="shell.nix" |
39 | | - if [[ ! -f "${shell}" ]]; then |
40 | | - shell="default.nix" |
41 | | - fi |
42 | | - |
43 | | - if [[ ! -f "${shell}" ]]; then |
44 | | - fail "use nix: shell.nix or default.nix not found in the folder" |
45 | | - fi |
46 | | - |
47 | | - local dir="${PWD}"/.direnv |
48 | | - local default="${dir}/default" |
49 | | - if [[ ! -L "${default}" ]] || [[ ! -d `readlink "${default}"` ]]; then |
50 | | - local wd="${dir}/env-`md5sum "${shell}" | cut -c -32`" # TODO: Hash also the nixpkgs version? |
51 | | - mkdir -p "${wd}" |
52 | | - |
53 | | - local drv="${wd}/env.drv" |
54 | | - if [[ ! -f "${drv}" ]]; then |
55 | | - log_status "use nix: deriving new environment" |
56 | | - IN_NIX_SHELL=1 nix-instantiate --add-root "${drv}" --indirect "${shell}" > /dev/null |
57 | | - nix-store -r `nix-store --query --references "${drv}"` --add-root "${wd}/dep" --indirect > /dev/null |
58 | | - fi |
59 | | - |
60 | | - rm -f "${default}" |
61 | | - ln -s `basename "${wd}"` "${default}" |
62 | | - fi |
63 | | - |
64 | | - local drv=`readlink -f "${default}/env.drv"` |
65 | | - local dump="${dir}/dump-`md5sum ".envrc" | cut -c -32`-`md5sum ${drv} | cut -c -32`" |
66 | | - |
67 | | - if [[ ! -f "${dump}" ]] || [[ "${XDG_CONFIG_DIR}/direnv/direnvrc" -nt "${dump}" ]]; then |
68 | | - log_status "use nix: updating cache" |
69 | | - |
70 | | - old=`find "${dir}" -name 'dump-*'` |
71 | | - nix-shell "${drv}" --show-trace "$@" --run 'direnv dump' > "${dump}" |
72 | | - rm -f ${old} |
73 | | - fi |
74 | | - |
75 | | - direnv_load cat "${dump}" |
76 | | - |
77 | | - watch_file "${default}" |
78 | | - watch_file shell.nix |
79 | | - if [[ ${shell} == "default.nix" ]]; then |
80 | | - watch_file default.nix |
81 | | - fi |
82 | | -} |
83 | | - |
84 | 1 | use nix |
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