Add the parameter ansible_roles_diff_mode to enable Ansible diff mode

app/helpers/foreman_ansible/ansible_reports_helper.rb

@@ -36,7 +36,7 @@ def ansible_module_message(log)
         msg_json['results'].empty? ? msg_json['msg'] : msg_json['results']
       when 'template'
         get_results(msg_json) do |module_args, result|
-          _("Rendered template #{module_args['_original_basename']} to #{result['dest']}")
+          add_diff(_("Rendered template #{module_args['_original_basename']} to #{result['dest']}. "), result['dest'], result)
         end
       when 'service'
         get_results(msg_json) do |_, result|
@@ -56,12 +56,25 @@ def ansible_module_message(log)
         end
       when 'copy'
         get_results(msg_json) do |module_args, result|
-          _("Copy #{module_args['_original_basename']} to #{result['dest']}")
+          add_diff(_("Copy #{module_args['_original_basename']} to #{result['dest']}. "), result['dest'], result)
         end
       when 'command', 'shell'
         msg_json['stdout_lines']
       else
-        no_data_message
+        have_diff = false
+        get_results(msg_json) do |_, result|
+          if result['report_diff'].present?
+            have_diff = true
+            break
+          end
+        end
+        if have_diff
+          get_results(msg_json) do |module_args, result|
+            add_diff('', module_args['path'] || '', result) if result['report_diff'].present?
+          end
+        else
+          no_data_message
+        end
       end
     end
 
@@ -95,8 +108,10 @@ def show_full_error_message_value(message_value)
     def get_results(msg_json)
       results = msg_json.key?('results') ? msg_json['results'] : [msg_json]
       results.map do |result|
-        module_args = result.fetch('invocation', {}).fetch('module_args', {})
-        yield module_args, result
+        if result.is_a?(Hash)
+          module_args = result.fetch('invocation', {}).fetch('module_args', {})
+          yield module_args, result
+        end
       end
     end
 
@@ -106,5 +121,19 @@ def parsed_message_json(log)
       Foreman::Logging.exception('Error while parsing ansible message json', e)
       {}
     end
+
+    def add_diff(message, title, result)
+      diff = if result['report_diff'].blank?
+               _('No Diff')
+             else
+               # Add '\n' before the unified diff as the Javascript displaying the
+               # diff expects this.
+               link_to(_('Show Diff'), '#', data: { diff: "\n#{result['report_diff']}", title: title }, onclick: 'tfm.configReportsModalDiff.showDiff(this);')
+             end
+      # diff is already HTML safe and should not be escaped again. Hence escape
+      # the contents of message and concatenate it with diff and
+      # declare it HTML safe.
+      (h(message) + diff).html_safe # rubocop:disable Rails/OutputSafety
+    end
   end
 end

app/models/foreman_ansible/ansible_provider.rb

@@ -33,6 +33,7 @@ def proxy_command_options(template_invocation, host)
             ),
             :name => host.name,
             :check_mode => host.host_param('ansible_roles_check_mode'),
+            :diff_mode => host.host_param('ansible_roles_diff_mode'),
             :cleanup_working_dirs => cleanup_working_dirs?(host)
           )
         end

db/seeds.d/100_common_parameters.rb

@@ -1,6 +1,7 @@
 CommonParameter.without_auditing do
   params = [
-    { name: 'ansible_roles_check_mode', key_type: 'boolean', value: false }
+    { name: 'ansible_roles_check_mode', key_type: 'boolean', value: false },
+    { name: 'ansible_roles_diff_mode', key_type: 'boolean', value: false }
   ]
 
   params.each { |param| CommonParameter.find_or_create_by(param) }

test/fixtures/report.json

@@ -105,6 +105,17 @@
         "level": "notice"
       }
     },
+    {
+      "log": {
+        "sources": {
+          "source": "Copy one local file with diff"
+        },
+        "messages": {
+          "message": "{\"_ansible_no_log\": false, \"changed\": true, \"checksum\": \"ec4cddb45c3ce640bed61b3d8ab6c18e715dac78\", \"dest\": \"/tmp/test7.txt\", \"report_diff\": \"--- /tmp/test7.txt\\n+++ /tmp/test7.txt\\n@@ -0,0 +1 @@\\n+Hello\\n\", \"failed\": false, \"gid\": 0, \"group\": \"root\", \"invocation\": {\"module_args\": {\"_original_basename\": \"test7.txt\", \"attributes\": null, \"backup\": false, \"checksum\": \"ec4cddb45c3ce640bed61b3d8ab6c18e715dac78\", \"content\": null, \"delimiter\": null, \"dest\": \"/tmp/test7.txt\", \"directory_mode\": null, \"follow\": false, \"force\": true, \"group\": \"root\", \"local_follow\": null, \"mode\": 256, \"owner\": \"root\", \"regexp\": null, \"remote_src\": null, \"selevel\": null, \"serole\": null, \"setype\": null, \"seuser\": null, \"src\": \"/root/.ansible/tmp/ansible-tmp-1671670677.05-7408-75605497546833/source\", \"unsafe_writes\": false, \"validate\": null}}, \"md5sum\": null, \"mode\": \"0400\", \"module\": \"copy\", \"owner\": \"root\", \"secontext\": \"unconfined_u:object_r:admin_home_t:s0\", \"size\": 6, \"src\": \"/root/.ansible/tmp/ansible-tmp-1671670677.05-7408-75605497546833/source\", \"state\": \"file\", \"uid\": 0}"
+        },
+        "level": "notice"
+      }
+    },
     {
       "log": {
         "sources": {

test/unit/helpers/ansible_reports_helper_test.rb

@@ -5,6 +5,8 @@
 class AnsibleReportsHelperTest < ActiveSupport::TestCase
   include ForemanAnsible::AnsibleReportsHelper
   include ActionView::Helpers::TagHelper
+  include ActionView::Helpers::UrlHelper
+  include ERB::Util
 
   test 'module message extraction' do
     log_value = <<-ANSIBLELOG.strip_heredoc
@@ -80,10 +82,11 @@ class AnsibleReportsHelperTest < ActiveSupport::TestCase
       'No additional data',
       ['Cron job: 0 5,2 * * * date > /dev/null (disabled: false)', 'Cron job: 0 5,2 * * * df > /dev/null (disabled: false)'],
       ['Cron job: 0 5,2 * * * hostname > /dev/null (disabled: false)'],
-      ['Rendered template test1.txt.j2 to /tmp/test1.txt', 'Rendered template test2.txt.j2 to /tmp/test2.txt'],
-      ['Rendered template test3.txt.j2 to /tmp/test3.txt'],
-      ['Copy test4.txt to /tmp/test4.txt', 'Copy test5.txt to /tmp/test5.txt'],
-      ['Copy test6.txt to /tmp/test6.txt'],
+      ['Rendered template test1.txt.j2 to /tmp/test1.txt. No Diff', 'Rendered template test2.txt.j2 to /tmp/test2.txt. No Diff'],
+      ['Rendered template test3.txt.j2 to /tmp/test3.txt. No Diff'],
+      ['Copy test4.txt to /tmp/test4.txt. No Diff', 'Copy test5.txt to /tmp/test5.txt. No Diff'],
+      ['Copy test6.txt to /tmp/test6.txt. No Diff'],
+      ["Copy test7.txt to /tmp/test7.txt. <a data-diff=\"\n--- /tmp/test7.txt\n+++ /tmp/test7.txt\n@@ -0,0 +1 @@\n+Hello\n\" data-title=\"/tmp/test7.txt\" onclick=\"tfm.configReportsModalDiff.showDiff(this);\" href=\"#\">Show Diff</a>"],
       ['Service chronyd started (enabled: )', 'Service firewalld started (enabled: )'],
       ['Service chronyd started (enabled: )']
     ]