.envrc

   1 # manual config
   2 nix_version=2.3
   3 nix_openpgp=B541D55301270E0BCF15CA5D8170B4726D7198DE
   4 nixpkgs_channel=nixos-19.09-small
   5 nixshell_sources=(.envrc shell.nix $(test ! -d shell || find shell -type f -not -name "*~" | sort))
   6
   7 # nix
   8 if ! has nix || test "$(nix --version)" != "nix (Nix) $nix_version"
   9 then log_status "installing Nix core tools"
  10         if test ! -e .config/nix/install -o ! -e .config/nix/install.asc
  11         then
  12                 mkdir -p .config/nix
  13                 (cd .config/nix; curl -OO https://nixos.org/releases/nix/nix-"$nix_version"/{install,install.asc})
  14                 gpg2 --keyserver hkp://keys.gnupg.net --recv-keys "$nix_openpgp"
  15         fi
  16         test -e ~/.nix-profile/etc/profile.d/nix.sh || {
  17                 gpg --verify .config/nix/install.asc
  18                 sh .config/nix/install
  19         }
  20         . ~/.nix-profile/etc/profile.d/nix.sh
  21 fi
  22
  23 # nixpkgs
  24 if test ! -e .config/nixpkgs-channel/$nixpkgs_channel.nix
  25 then log_status "installing nixpkgs from $nixpkgs_channel (This may take some time. To update: delete .config/nixpkgs-channel/$nixpkgs_channel.nix)"
  26   rev=$(curl -L https://nixos.org/channels/"$nixpkgs_channel"/git-revision | head -n1 | tr -dC 'a-z0-9')
  27   sha256=$(nix-prefetch-url --unpack https://github.com/NixOS/nixpkgs-channels/archive/"$rev".tar.gz)
  28   mkdir -p .config/nixpkgs-channel
  29   echo >.config/nixpkgs-channel/$nixpkgs_channel.nix "builtins.fetchTarball {url=\"https://github.com/NixOS/nixpkgs-channels/archive/$rev.tar.gz\"; sha256=\"$sha256\";}"
  30 else log_status "using nixpkgs from .config/nixpkgs-channel/$nixpkgs_channel.nix"
  31 fi
  32 watch_file .config/nixpkgs-channel/$nixpkgs_channel.nix
  33 # Get the store path of this nixpkgs,
  34 # it will not be registered as a root for the garbage-collector
  35 # but will be preserved as long as it is used by shell.nix
  36 # which itself will produce a registered derivation.
  37 nixpkgs=$(nix-instantiate --eval .config/nixpkgs-channel/$nixpkgs_channel.nix)
  38 nixpkgs=${nixpkgs#'"'}
  39 nixpkgs=${nixpkgs%'"'}
  40 export NIX_PATH="${NIX_PATH:+$NIX_PATH:}nixpkgs=$nixpkgs"
  41
  42 # nix-shell
  43 has shasum || fail "shasum is needed to cache environment"
  44 for e in "${nixshell_sources[@]}"
  45 do watch_file "$e"; done
  46 hash=$(for e in "${nixshell_sources[@]}"; do shasum -a 256 "$e"; done | shasum -a 256 | cut -c -64)
  47 if test -e ".cache/nix-shell/$hash/dump"
  48 then log_status "reusing .cache/nix-shell/$hash/"
  49 else log_status "building .cache/nix-shell/$hash/"
  50   trap "rm -rf '$PWD/.cache/nix-shell/$hash'" EXIT
  51   mkdir -p ".cache/nix-shell/$hash"
  52   # Register the derivation as a root for the garbage-collector
  53   nix-instantiate >/dev/null ./shell.nix \
  54    --indirect --add-root .cache/nix-shell/"$hash"/shell.drv \
  55    ${TRACE:+--show-trace} \
  56    ${OFFLINE:+--option substituters ""}
  57   nix-store >/dev/null \
  58    --indirect --add-root .cache/nix-shell/"$hash"/shell.dep \
  59    ${OFFLINE:+--option substituters ""} \
  60    --realise $(nix-store --query --references .cache/nix-shell/"$hash"/shell.drv)
  61   # Dump the environment from within the nix-shell
  62   local dump
  63   dump="$(mktemp .cache/nix-shell/$hash/dump-XXXXXXXX)"
  64   nix-shell >"$dump" ${TRACE:+--show-trace} --pure \
  65    --run "$(command -v direnv) dump" \
  66    ${OFFLINE:+--option substituters ""}
  67   # Unregister previous derivations
  68   find .cache/nix-shell -mindepth 1 -maxdepth 1 -not -name "$hash" -exec rm -rf {} +
  69   mv -f "$dump" .cache/nix-shell/"$hash"/dump
  70   trap "" EXIT
  71 fi
  72 # Load the cached environment
  73 direnv_load cat .cache/nix-shell/"$hash"/dump
  74 # Re-run the shellHook to update envvars like GPG_TTY
  75 eval "$shellHook"