[#210] Add activation script for darwin system and provide a usage example

Problem: It's possible to use 'deploy-rs' for deploying 'darwinSystem'
configuration from 'nix-darwin' to a darwin system. However, there is no
dedicated activatiot script for darwin and thus one has to come up with
'custom' activation script.

Solution:
1) Add 'darwin' attribute to 'lib.activate' that provides a script that
   should be used to activate 'darwinSystem' config with 'deploy-rs'.
2) Add a new 'examples/darwin' example that provides simple flake for
   deploying configuration to a darwin target.

1 files changed, 39 insertions, 0 deletions

diff --git a/examples/darwin/flake.nix b/examples/darwin/flake.nix
new file mode 100644
index 0000000..d5d7ae8
--- /dev/null
+++ b/examples/darwin/flake.nix
@@ -0,0 +1,39 @@
+{
+  description = "Deploy simple 'darwinSystem' to a darwin machine";
+
+  inputs.deploy-rs.url = "github:serokell/deploy-rs";
+  inputs.darwin.url = "github:LnL7/nix-darwin";
+
+  outputs = { self, nixpkgs, deploy-rs, darwin }: {
+    darwinConfigurations.example = darwin.lib.darwinSystem {
+      system = "x86_64-darwin";
+      modules = [
+        ({lib, config, pkgs, ...}: {
+          services.nix-daemon.enable = true;
+          nix = {
+            settings = {
+              trusted-users = [ "rvem" ];
+            };
+            extraOptions = ''
+              experimental-features = flakes nix-command
+            '';
+          };
+          # nix commands are added to PATH in the zsh config
+          programs.zsh.enable = true;
+        })
+      ];
+    };
+    deploy = {
+      # remoteBuild = true; # Uncomment in case the system you're deploying from is not darwin
+      nodes.example = {
+        hostname = "localhost";
+        profiles.system = {
+          user = "root";
+          path = deploy-rs.lib.x86_64-darwin.activate.darwin self.darwinConfigurations.example;
+        };
+      };
+    };
+
+    checks = builtins.mapAttrs (system: deployLib: deployLib.deployChecks self.deploy) deploy-rs.lib;
+  };
+}