Override autogenerated file path with variable

manifests/init.pp

@@ -22,26 +22,31 @@
   Sensitive[String] $password,
   Optional[String]  $group    = $user,
   Optional[String]  $filename = '.netrc',
+  Optional[Stdlib::Absolutepath] $file_path = undef,
 ) {
-  $file_path = $user ? {
+  $user_file = $user ? {
     'root'  => "/root/${filename}",
     default => "/home/${user}/${filename}",
   }
-  if !defined(Concat[$file_path]) {
-    concat { $file_path:
+  $real_file_path = $file_path ? {
+    undef   => $user_file,
+    default => $file_path,
+  }
+  if !defined(Concat[$real_file_path]) {
+    concat { $real_file_path:
       ensure         => present,
       mode           => '0600',
       owner          => $user,
       group          => $group,
       ensure_newline => true,
     }
-    concat::fragment { "${file_path}-header":
-      target  => $file_path,
+    concat::fragment { "${real_file_path}-header":
+      target  => $real_file_path,
       content => '# File content managed by Puppet',
     }
   }
   concat::fragment { "${user}-${machine}-${login}":
-    target  => $file_path,
+    target  => $real_file_path,
     content => Sensitive(epp('netrc/netrc.epp',
       {
         machine  => $machine,