add flake app to reboot vms on servers

flake.nix

@@ -36,6 +36,7 @@
     let
       system = "x86_64-linux";
       pkgs = nixpkgs.legacyPackages.${system};
+      lib = pkgs.lib;
       pkgs-unstable = nixpkgs-unstable.legacyPackages.${system};
       machines = import ./nixos/machines;
       # TODO: Maybe use mergeAttrLists
@@ -102,5 +103,56 @@
       checks = builtins.mapAttrs
         (system: deployLib: deployLib.deployChecks self.deploy)
         deploy-rs.lib;
+
+      apps.${system} =
+        let
+          hostNames = builtins.concatStringsSep " " (builtins.map (host: "\"${host.config.networking.fqdn}\"") (builtins.attrValues self.nixosConfigurations));
+        in
+        {
+          reboot-all-vms =
+            let
+              reboot-all-vms = pkgs.writeScriptBin "reboot-all-vms" ''
+                hostNames=(${hostNames})
+                for hostName in ''${hostNames[@]}; do
+                  units=$(${pkgs.openssh}/bin/ssh root@$hostName systemctl list-units --all)
+                  microvmUnits=$(${pkgs.coreutils}/bin/echo "$units" | ${pkgs.gnugrep}/bin/grep 'microvm@.*\.service' | ${pkgs.gawkInteractive}/bin/awk '{print $1}')
+                  if [ -n "$microvmUnits" ]; then
+                    for microvmUnit in "$microvmUnits"; do
+                      ${pkgs.coreutils}/bin/echo "Restarting $microvmUnit on $hostName"
+                      ${pkgs.openssh}/bin/ssh root@$hostName systemctl restart "$microvmUnit"
+                    done
+                  fi
+                done
+              '';
+            in
+            {
+              type = "app";
+              program = "${reboot-all-vms}/bin/reboot-all-vms";
+            };
+
+          reboot-vm =
+            let
+              reboot-vm = pkgs.writeScriptBin "reboot-vm" ''
+                if [ -z "$1" ]; then
+                  ${pkgs.coreutils}/bin/echo "Please provide a VM name!"
+                  exit 1
+                fi
+
+                hostNames=(${hostNames})
+                unitName="microvm@$1.service"
+                for hostName in ''${hostNames[@]}; do
+                  units=$(${pkgs.openssh}/bin/ssh root@$hostName systemctl list-units --all)
+                  if [[ "''${units[@]}" =~ "$unitName" ]]; then
+                    ${pkgs.coreutils}/bin/echo "Restarting $unitName on $hostName"
+                    ${pkgs.openssh}/bin/ssh root@$hostName systemctl restart "$unitName"
+                  fi
+                done
+              '';
+            in
+            {
+              type = "app";
+              program = "${reboot-vm}/bin/reboot-vm";
+            };
+        };
     };
 }