.envrc

   1 # manual config
   2 nix_version=2.3.2
   3 nix_openpgp=B541D55301270E0BCF15CA5D8170B4726D7198DE
   4 nixpkgs_channel=nixos-unstable-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) $nix_version"
   9 then log_status "installing Nix core tools"
  10   gpg2 --keyserver hkp://wwwkeys.de.pgp.net:80 --recv-keys "$nix_openpgp"
  11   {
  12   flock --exclusive 3
  13   if test ! -s .config/nix/install -o ! -s .config/nix/install.asc
  14   then
  15     mkdir -p .config/nix
  16     (cd .config/nix; curl -OO https://nixos.org/releases/nix/nix-"$nix_version"/{install,install.asc})
  17   fi
  18   test -e ~/.nix-profile/etc/profile.d/nix.sh || {
  19     gpg --verify .config/nix/install.asc &&
  20     sh .config/nix/install || {
  21       log_error "cannot install nix-$nix_version"
  22       return 1
  23     }
  24   }
  25   . ~/.nix-profile/etc/profile.d/nix.sh
  26   } 3>>.config/nix/install
  27 fi
  28
  29 # nixpkgs
  30 mkdir -p .config/nixpkgs-channel
  31 {
  32 flock --exclusive 3
  33 if test ! -s .config/nixpkgs-channel/$nixpkgs_channel.nix
  34 then log_status "installing nixpkgs from $nixpkgs_channel (This may take some time. To update: delete .config/nixpkgs-channel/$nixpkgs_channel.nix)"
  35   rev=$(curl -L https://nixos.org/channels/"$nixpkgs_channel"/git-revision | head -n1 | tr -dC 'a-z0-9')
  36   sha256=$(nix-prefetch-url --unpack https://github.com/NixOS/nixpkgs-channels/archive/"$rev".tar.gz)
  37   echo >.config/nixpkgs-channel/$nixpkgs_channel.nix \
  38    "builtins.fetchTarball {url=\"https://github.com/NixOS/nixpkgs-channels/archive/$rev.tar.gz\"; sha256=\"$sha256\";}"
  39 else log_status "using nixpkgs from .config/nixpkgs-channel/$nixpkgs_channel.nix"
  40 fi
  41 } 3>>.config/nixpkgs-channel/$nixpkgs_channel.nix
  42 watch_file .config/nixpkgs-channel/$nixpkgs_channel.nix
  43 # Used in shell.nix
  44 export nixpkgs_channel
  45 # Get the store path of this nixpkgs,
  46 # it will not be registered as a root for the garbage-collector
  47 # but will be preserved as long as it is used by shell.nix
  48 # which itself will produce a registered derivation.
  49 #nixpkgs=$(nix-instantiate --eval .config/nixpkgs-channel/$nixpkgs_channel.nix)
  50 #nixpkgs=${nixpkgs#'"'}
  51 #nixpkgs=${nixpkgs%'"'}
  52 #export NIX_PATH="nixpkgs=$nixpkgs${NIX_PATH:+:$NIX_PATH}"
  53
  54 # nix-shell
  55 has shasum || { log_error "shasum is needed to cache environment"; return 1; }
  56 for e in "${nixshell_sources[@]}"
  57 do watch_file "$e"; done
  58 hash=$(shasum -a 256 "${nixshell_sources[@]}" | shasum -a 256 | cut -c -64)
  59 cache=.cache/nix-shell/"$hash"
  60 if test -e "$cache/dump"
  61 then
  62   log_status "reusing $cache/"
  63   {
  64   flock --shared 3
  65   # Load the cached environment
  66   direnv_load sh -c "cat >\$DIRENV_DUMP_FILE_PATH $cache/dump"
  67   # Re-run the shellHook to update envvars like GPG_TTY,
  68   # and run gpg-connect-agent updatestartuptty /bye
  69   eval "$shellHook"
  70   } 3<$cache/dump
  71 else
  72   log_status "building $cache/"
  73   mkdir -p "$cache"
  74   {
  75   flock --exclusive 3
  76   # Register the derivation as a root for the garbage-collector,
  77   # then cache a dump of the environment from within the nix-shell,
  78   # then unregister previous derivations,
  79   # then load the cached environment.
  80   nix-instantiate >/dev/null ./shell.nix --indirect --add-root "$cache"/shell.drv \
  81    ${TRACE:+--show-trace} \
  82    ${OFFLINE:+--option substituters ""} &&
  83   nix-store >/dev/null --indirect --add-root "$cache"/shell.dep \
  84    --realise $(nix-store --query --references $cache/shell.drv) \
  85    ${OFFLINE:+--option substituters ""} &&
  86   direnv_load sh -c "nix-shell ${TRACE:+--show-trace} --pure \
  87    --run \"$direnv dump | tee $cache/dump >\$DIRENV_DUMP_FILE_PATH\" \
  88    ${OFFLINE:+--option substituters ""}" &&
  89   find .cache/nix-shell -mindepth 1 -maxdepth 1 -not -name "$hash" -exec rm -rf {} + || {
  90     rm -rf "$PWD/.cache/nix-shell/$hash"
  91     log_error "cannot build shell.nix"
  92     return 1
  93   }
  94   } 3>$cache/dump
  95 fi