nix,steveej-t480s-work: introduce pure versioning

Justfile

@@ -1,14 +1,19 @@
 _usage:
 	just -l
 
+_get_nix_path versionsPath:
+	echo $(set -x; nix-build --no-link --show-trace {{invocation_directory()}}/nix/default.nix -A channelSources --argstr versionsPath  {{versionsPath}} --argstr rebuildarg "dummy")
+
 _device recipe dir +moreargs="":
 	#!/usr/bin/env bash
 	set -ex
+	source $(just -v _get_nix_path {{invocation_directory()}}/{{dir}}/versions.nix)
 	$(set -x; nix-build --no-link --show-trace $(dirname {{dir}})/default.nix -A recipes.{{recipe}} --argstr dir {{dir}} {{moreargs}})
 
 _render_templates:
 	#!/usr/bin/env bash
 	set -ex
+	source $(just -v _get_nix_path {{invocation_directory()}}/nix/variables/versions.nix)
 	nix/scripts/pre-eval-fixed.sh nix/home-manager/profiles/dotfiles/vcsh{.tmpl,}.nix
 
 _rebuild-device dir rebuildarg="dry-activate" +moreargs="": _render_templates

nix/default.nix

@@ -0,0 +1,25 @@
+{ versionsPath }:
+
+{
+  channelSources =
+    let
+      # channelVersions = (import ((builtins.getEnv "PWD")+"/${dir}/versions.nix"));
+      channelVersions = (import versionsPath);
+      mkChannelSource = channel: builtins.fetchGit {
+        # Descriptive name to make the store path easier to identify
+        url = "https://github.com/NixOS/nixpkgs-channels/";
+        # Commit hash for nixos-unstable as of 2018-09-12
+        # `git ls-remote https://github.com/nixos/nixpkgs-channels nixos-unstable`
+        rev = (builtins.getAttr channel channelVersions);
+        name = "nixpkgs-channels-${channel}";
+      };
+      nix_path = builtins.foldl' (sum: elem: sum +":" + builtins.concatStringsSep "=" elem) "" [
+        [ "nixpkgs" (mkChannelSource "channelsNixosStable") ]
+        [ "nixos" (mkChannelSource "channelsNixosStable") ]
+        [ "channels-nixos-stable" (mkChannelSource "channelsNixosStable") ]
+        [ "channels-nixos-unstable" (mkChannelSource "channelsNixosUnstable") ]
+      ];
+    in (import (mkChannelSource "channelsNixosStable") {}).writeText "channels.rc" ''
+      export NIX_PATH=${nix_path}
+    '';
+  }

nix/home-manager/configuration/graphical-fullblown.nix

@@ -4,7 +4,7 @@
 
 let
   # gitpkgs = import /home/steveej/src/github/NixOS/nixpkgs {};
-  unstablepkgs = import <nixos-unstable> { config = config.nixpkgs.config; };
+  unstablepkgs = import <channels-nixos-unstable> { config = config.nixpkgs.config; };
 
 in {
   imports = [

nix/home-manager/configuration/graphical-removable.nix

@@ -3,7 +3,8 @@
 ... }:
 
 let
-  unstablepkgs = import <nixos-unstable> { config = config.nixpkgs.config; };
+  unstablepkgs = import <channels-nixos-unstable> { config = config.nixpkgs.config; };
+
 in {
   imports = [
     ../profiles/common.nix
@@ -52,9 +53,6 @@ in {
     };
   };
 
-  # gitpkgs = import /home/steveej/src/github/NixOS/nixpkgs {};
-  # unstablepkgs = import <nixos-unstable> { config = { allowUnfree = true; }; };
-
   home.sessionVariables = {
   };
 

nix/home-manager/profiles/nix-channels.nix

@@ -6,14 +6,16 @@
 let
 in {
   home.file.".nix-channels".text = ''
-    https://nixos.org/channels/nixos-18.09 nixos
-    https://nixos.org/channels/nixos-unstable nixos-unstable
   '';
 
   home.activation.removeExistingNixChannels = config.lib.dag.entryBefore ["checkLinkTargets"] ''
     $DRY_RUN_CMD ${pkgs.writeScript "activation-script" ''
     set -ex
     if test -f $HOME/.nix-channels; then
+      echo Uninstalling available channels...
+      while read url channel; do
+        nix-channel --remove $channel
+      done < $HOME/.nix-channel
       echo Moving existing file away...
       touch $HOME/.nix-channels.dummy
       mv --backup=numbered $HOME/.nix-channels.dummy $HOME/.nix-channels

nix/home-manager/programs/neovim.nix

@@ -3,7 +3,7 @@
 }:
 
 let
-  unstablepkgs = import <nixos-unstable> {};
+  unstablepkgs = import <channels-nixos-unstable> {};
 
 in {
   home.sessionVariables = {

nix/os/devices/default.nix

@@ -1,4 +1,4 @@
-{ pkgs ? import <nixpkgs> {}
+{ pkgs ? import <channels-nixos-stable> {}
 , ownLib ? import ../lib/default.nix { }
 , dir
 , rebuildarg

nix/os/devices/steveej-laptop/system.nix

@@ -5,7 +5,7 @@
 }:
 
 let
-  unstablepkgs = import <nixos-unstable> { config = config.nixpkgs; };
+  unstablepkgs = import <channels-nixos-unstable> { config = config.nixpkgs; };
 
 in {
   # The NixOS release to be compatible with for stateful data such as databases.

nix/os/devices/steveej-t480s-work/versions.nix

@@ -0,0 +1,4 @@
+{
+  channelsNixosStable = "7e88992a8c7b2de0bcb89182d8686b27bd93e46a";
+  channelsNixosUnstable = "44b02b52ea6a49674f124f50009299f192ed78bb";
+}

nix/scripts/pre-eval-fixed.sh

@@ -1,5 +1,6 @@
 #!/usr/bin/env bash
+set -xe
 INFILE="${1:?Please set arg1 to INFILE}"
 OUTFILE="${2:?Please set arg2 to OUTFILE}"
-hash=$(nix-build ${INFILE} --arg pkgs 'import <nixpkgs> {}' --arg config 'null' 2>&1 | grep -oE '[0-9a-z]{52}' | head -n1)
+hash=$(nix-build ${INFILE} --arg pkgs 'import <channels-nixos-stable> {}' --arg config 'null' 2>&1 | grep -oE '[0-9a-z]{52}' | head -n1)
 sed -E "s/0{52}/${hash}/" ${INFILE} > ${OUTFILE}

nix/variables/versions.nix

@@ -0,0 +1,4 @@
+{
+  channelsNixosStable = "7e88992a8c7b2de0bcb89182d8686b27bd93e46a";
+  channelsNixosUnstable = "44b02b52ea6a49674f124f50009299f192ed78bb";
+}

shell.nix

@@ -1,12 +1,15 @@
-with import <nixpkgs> {};
+{ ... }:
 
 let 
+  channels-nixos-stable-path = (builtins.fetchTarball https://github.com/NixOS/nixpkgs-channels/archive/7e88992a8c7b2de0bcb89182d8686b27bd93e46a.tar.gz);
+  channels-nixos-stable = import channels-nixos-stable-path {};
 
 in 
+with channels-nixos-stable;
 stdenv.mkDerivation {
   name = "infra-env";
   buildInputs = [
-    (with import <nixpkgs/nixos> { configuration = {}; }; with config.system.build; [ nixos-generate-config nixos-install nixos-enter manual.manpages ])
+    (with import (channels-nixos-stable-path+"/nixos") { configuration = {}; }; with config.system.build; [ nixos-generate-config nixos-install nixos-enter manual.manpages ])
     (pkgs.callPackage ./nix/pkgs/just.nix {})
     git-crypt
     vcsh