use install script

manifests/init.pp

@@ -156,16 +156,20 @@ class mastodon (
     group    => 'mastodon',
     require  => Vcsrepo['rbenv'],
   }
+  file { '/usr/local/bin/install_ruby.sh':
+    ensure  => $ensure,
+    content => template('mastodon/install_ruby.sh.erb'),
+    mode    => '0750',
+    owner   => 'mastodon',
+    group   => 'root',
+    require => Vcsrepo['ruby_build'],
+  }
   exec { 'install_ruby':
-    command     => "${mastodon_home}/.rbenv/bin/rbenv install 3.2.2",
-    path        => "${mastodon_home}/.rbenv/bin:/usr/sbin:/usr/bin:/sbin:/bin",
-    environment => [
-      'RUBY_CONFIGURE_OPTS=--with-jemalloc',
-    ],
-    user        => 'mastodon',
-    cwd         => "${mastodon_home}/.rbenv/",
-    creates     => "${mastodon_home}/.rbenv/versions/3.2.2/bin/ruby",
-    require     => Vcsrepo['ruby_build'],
+    command => '/usr/local/bin/install_ruby.sh',
+    user    => 'mastodon',
+    cwd     => "${mastodon_home}/.rbenv/",
+    creates => "${mastodon_home}/.rbenv/versions/3.2.2/bin/ruby",
+    require => File['/usr/local/bin/install_ruby.sh'],
   }
   # exec { 'set_global_ruby_version':
   #   command     => "${mastodon_home}/.rbenv/libexec/rbenv global 3.2.2",

templates/install_ruby.sh.erb

@@ -0,0 +1,8 @@
+#!/bin/bash
+set -euo pipefail
+
+su mastodon
+if [ ! -e "<%= @mastodon_home %>/.rbenv/versions/3.2.2/bin/ruby" ]; then
+    cd "<%= @mastodon_home %>"
+    RUBY_CONFIGURE_OPTS=--with-jemalloc "<%= @mastodon_home %>/.rbenv/bin/rbenv" install 3.2.2
+fi