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use lorri for envrc, faster better

shake
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commit
eefd8e1210
Signed by: Yann Esposito (Yogsototh) <yann.esposito@gmail.com> GPG Key ID: 7B19A4C650D59646
1 changed files with 1 additions and 153 deletions
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    153
      .envrc

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.envrc View File

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# Usage: use_nix [...]
#
# Load environment variables from `nix-shell`.
# If you have a `default.nix` or `shell.nix` one of these will be used and
# the derived environment will be stored at ./.direnv/env-<hash>
# and symlink to it will be created at ./.direnv/default.
# Dependencies are added to the GC roots, such that the environment remains persistent.
#
# The resulting environment is cached for better performance.
#
# To trigger switch to a different environment:
# `rm -f .direnv/default`
#
# To derive a new environment:
# `rm -rf .direnv/env-$(md5sum {shell,default}.nix 2> /dev/null | cut -c -32)`
#
# To remove cache:
# `rm -f .direnv/dump-*`
#
# To remove all environments:
# `rm -rf .direnv/env-*`
#
# To remove only old environments:
# `find .direnv -name 'env-*' -and -not -name `readlink .direnv/default` -exec rm -rf {} +`
#

set -eo pipefail

use_nix() {
# define all local variables
local shell f env_hash dir default wd drv dump path_backup
local files_to_watch=()

declare opt
declare OPTARG
declare OPTIND

while getopts ":s:w:" opt; do
case "${opt}" in
s)
shell="${OPTARG}"
files_to_watch=("${files_to_watch[@]}" "${shell}")
;;
w)
files_to_watch=("${files_to_watch[@]}" "${OPTARG}")
;;
:)
>&2 echo "Invalid option: $OPTARG requires an argument"
;;
\?)
>&2 echo "Invalid option: $OPTARG"
exit 1
;;
esac
done
shift $((OPTIND -1))

if [[ -z "${shell}" ]]; then
>&2 echo "ERR: no shell was given"
exit 1
fi

for f in "${files_to_watch[@]}"; do
if ! [[ -f "${f}" ]]; then
>&2 echo "cannot watch file ${f} because it does not exist"
exit 1
fi
done

# compute the hash of all the files that makes up the development environment
env_hash="$(hashContents "${files_to_watch[@]}")"

dir="$(direnv_layout_dir)"
default="${dir}/default"
if [[ ! -L "${default}" ]] || [[ ! -d $(readlink "${default}") ]]; then
wd="${dir}/env-${env_hash}"
mkdir -p "${wd}"

drv="${wd}/env.drv"
if [[ ! -f "${drv}" ]]; then
log_status "use nix: deriving new environment"
IN_NIX_SHELL=1 nix-instantiate --add-root "${drv}" --indirect "${shell}" > /dev/null
nix-store -r $(nix-store --query --references "${drv}") --add-root "${wd}/dep" --indirect > /dev/null
fi

rm -f "${default}"
ln -s $(basename "${wd}") "${default}"
fi

drv=$(readlink "${default}/env.drv")
dump="${dir}/dump-$(hashFile ".envrc")-$(hashFile ${drv})"

if [[ ! -f "${dump}" ]] || [[ "${XDG_CONFIG_DIR}/direnv/direnvrc" -nt "${dump}" ]]; then
log_status "use nix: updating cache"

old=$(find "${dir}" -name 'dump-*')
nix-shell --pure "${drv}" --show-trace --run "$(join_args "$direnv" dump bash)" > "${dump}"
rm -f ${old}
fi

# evaluate the dump created by nix-shell earlier, but have to merge the PATH
# with the current PATH
# NOTE: we eval the dump here as opposed to direnv_load it because we don't
# want to persist environment variables coming from the shell at the time of
# the dump. See https://github.com/direnv/direnv/issues/405 for context.
path_backup="${PATH}"
eval $(cat "${dump}")
export PATH="${PATH}:${path_backup}"

for f in "${files_to_watch[@]}"; do
watch_file "${f}"
done
}

hashContents() {
if has md5sum; then
cat "${@}" | md5sum | cut -c -32
elif has md5; then
cat "${@}" | md5 -q
fi
}

hashFile() {
if has md5sum; then
md5sum "${@}" | cut -c -32
elif has md5; then
md5 -q "${@}"
fi
}

fail() {
log_error "${@}"
exit 1
}

validateVersion() {
local version="$("${direnv}" version)"
local major="$(echo "${version}" | cut -d. -f1)"
local minor="$(echo "${version}" | cut -d. -f2)"
local patch="$(echo "${version}" | cut -d. -f3)"

if [[ "${major}" -gt 2 ]]; then return 0; fi
if [[ "${major}" -eq 2 ]] && [[ "${minor}" -gt 18 ]]; then return 0; fi
if [[ "${major}" -eq 2 ]] && [[ "${minor}" -eq 18 ]] && [[ "${patch}" -ge 2 ]]; then return 0; fi
return 1
}

if ! validateVersion; then
echo "This .envrc requires direnv version 2.18.2 or above."
exit 1
fi

use_nix -s shell.nix
eval "$(lorri direnv)"

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