3 files changed, 98 insertions, 0 deletions
diff --git a/pkgs/yo/README.md b/pkgs/yo/README.md
new file mode 100644
index 0000000..a308057
--- /dev/null
+++ b/pkgs/yo/README.md
@@ -0,0 +1,2 @@
+# `nixos.rb`
+A small Ruby library for writing `nixos-rebuild` replacements.
diff --git a/pkgs/yo/default.nix b/pkgs/yo/default.nix
new file mode 100644
index 0000000..06e88d4
--- /dev/null
+++ b/pkgs/yo/default.nix
@@ -0,0 +1,59 @@
+{pkgs, ...}: let
+  yo = pkgs.writeText "yo.rb" ''
+    require '${./nixos.rb}'
+
+    FLAKE_PATH = "/home/collin/nixos"
+
+    case ARGV[0]
+      when "deploy", "dep"
+        hostname = ARGV[1] or abort "must specify hostname to build"
+        ssh_host = ARGV[2] or abort "must specify ssh host to target"
+
+        store_path = Nix.build_configuration(
+          flake_path: FLAKE_PATH,
+          hostname: hostname
+        )
+        Nix.switch_to_configuration_remote(store_path: store_path, ssh_host: ssh_host, use_magic_rollback: true)
+      when "switch", "sw"
+        store_path = Nix.build_configuration(
+          flake_path: FLAKE_PATH,
+          hostname: `hostname`.chomp
+        )
+        Nix.switch_to_configuration(
+          store_path: store_path,
+          verb: "switch",
+          sudo_cmd: "run0 --background="
+        )
+      when "boot"
+        store_path = Nix.build_configuration(
+          flake_path: FLAKE_PATH,
+          hostname: `hostname`.chomp
+        )
+        Nix.switch_to_configuration(
+          store_path: store_path,
+          verb: "boot",
+          sudo_cmd: "run0 --background="
+        )
+      when "test"
+        store_path = Nix.build_configuration(
+          flake_path: FLAKE_PATH,
+          hostname: `hostname`.chomp
+        )
+        Nix.switch_to_configuration(
+          store_path: store_path,
+          verb: "test",
+          sudo_cmd: "run0 --background="
+        )
+      when "build"
+        hostname = ARGV[1] or `hostname`.chomp
+
+        Nix.build_configuration(
+          flake_path: FLAKE_PATH,
+          hostname: hostname
+        )
+    end
+  '';
+in
+  pkgs.writeShellScriptBin "yo" ''
+    exec ${pkgs.ruby}/bin/ruby ${yo} "$@"
+  ''
diff --git a/pkgs/yo/nixos.rb b/pkgs/yo/nixos.rb
new file mode 100644
index 0000000..73a1872
--- /dev/null
+++ b/pkgs/yo/nixos.rb
@@ -0,0 +1,37 @@
+module Nix
+  def build_configuration(flake_path:, hostname:)
+    flake_target = "#{flake_path}#nixosConfigurations.'#{hostname}'.config.system.build.toplevel"
+    `nix build --no-link --print-out-paths #{flake_target}`.chomp.tap do
+      raise "Build command failed" unless $?.success?
+    end
+  end
+
+  def switch_to_configuration(store_path:, verb:, sudo_cmd: "sudo")
+    create_gen_cmd = "nix build --no-link --profile /nix/var/nix/profiles/system #{store_path}"
+    switch_cmd = "#{store_path}/bin/switch-to-configuration #{verb}"
+    system("#{sudo_cmd} bash -c '#{create_gen_cmd}; #{switch_cmd}'") or raise "Switch command failed"
+  end
+
+  def switch_to_configuration_remote(store_path:, ssh_host:, use_magic_rollback: false)
+    system("nix copy --to ssh://#{ssh_host} #{store_path}") or raise "Copy closure command failed"
+
+    create_gen_cmd = "nix build --no-link --profile /nix/var/nix/profiles/system #{store_path}"
+    switch_cmd = "#{store_path}/bin/switch-to-configuration switch"
+
+    if use_magic_rollback
+      test_cmd = "#{store_path}/bin/switch-to-configuration test"
+      system(%[ssh #{ssh_host} 'bash -c "#{test_cmd}; shutdown -r +5"']) or raise "Remote test command failed"
+
+      puts <<~MSG
+        Remote deployment complete.
+        If everything works, press ENTER to confirm and cancel rollback.
+        If SSH dies, it will restart (reversing changes) automatically in 5 minutes
+      MSG
+      $stdin.gets
+
+      system(%[ssh #{ssh_host} 'bash -c "shutdown -c; #{create_gen_cmd}; #{switch_cmd}"']) or raise "Remote switch command failed"
+    else
+      system(%[ssh #{ssh_host} 'bash -c "#{create_gen_cmd}; #{switch_cmd}"']) or raise "Remote switch command failed"
+    end
+  end
+end