switch reusable script to package, facilitating inspection and reuse

deployment/check/data-model-ssh/nixosTest.nix

@@ -15,12 +15,12 @@ let
       "ServerAliveInterval=1"
     ];
   };
-  deployment =
+  deploy =
     (import ../common/data-model.nix {
       inherit system;
       config = deployment-config;
       # opt not to pass `inputs`, as we could only pass serializable arguments through to its self-call
-    })."ssh-deployment".ssh-host;
+    })."ssh-deployment".ssh-host.run;
 in
 {
   _class = "nixosTest";
@@ -46,6 +46,7 @@ in
     {
       environment.systemPackages = with pkgs; [
         jq
+        deploy
       ];
 
       system.extraDependenciesFromModule =
@@ -63,7 +64,7 @@ in
 
     with subtest("Run the deployment"):
       deployer.succeed("""
-        ${deployment.run}
+        ${lib.getExe deploy}
       """)
       ssh.wait_for_unit("multi-user.target")
       ssh.succeed("su - operator -c hello 1>&2")

deployment/data-model.nix

@@ -20,7 +20,7 @@ let
     ;
   toBash =
     v:
-    lib.replaceStrings [ "\"" ] [ "\\\\\"" ] (
+    lib.replaceStrings [ "\"" ] [ "\\\"" ] (
       if lib.isPath v || builtins.isNull v then
         toString v
       else if lib.isString v then
@@ -112,7 +112,7 @@ let
             type = types.path;
           };
           run = mkOption {
-            type = types.str;
+            type = types.package;
             # error: The option `ssh-deployment.ssh-host.run' is read-only, but it's set multiple times.
             # readOnly = true;
             default =
@@ -146,7 +146,7 @@ let
                   deployment_type = "ssh-host";
                 };
               in
-              ''
+              pkgs.writeShellScriptBin "deploy-ssh.sh" ''
                 env ${
                   toString (lib.mapAttrsToList (k: v: "${k}=\"${toBash v}\"") environment)
                 } bash ./deployment/run/ssh-single-host/run.sh