Added rendering of custom mustache templates to $(sys.workdir)/modules

With this change mustache templates found in modules/mustache (relative to the
root of the policy set) are rendered to $(sys.workdir)/modules using datastate()
from the update.cf policy entry.

Ticket: ENT-10793
Changelog: Title

cfe_internal/update/update_policy.cf

@@ -784,7 +784,9 @@ bundle agent modules_presence
   vars:
     "_vendored_dir" string => "$(this.promise_dirname)/../../modules/packages/vendored/";
     "_override_dir" string => "$(this.promise_dirname)/../../modules/packages/";
+    "_custom_template_dir" string => "$(this.promise_dirname)/../../modules/mustache/";
     "_vendored_paths" slist => findfiles("$(_vendored_dir)*.mustache");
+    "_custom_template_paths" slist => findfiles("$(_custom_template_dir)*.mustache"), if => isdir( "$(_custom_template_dir)" );
     "_package_paths" slist => filter("$(_override_dir)vendored", _package_paths_tmp, "false", "true", 999);
     windows::
       "_package_paths_tmp" slist => findfiles("\Q$(_override_dir)\E*");
@@ -798,7 +800,8 @@ bundle agent modules_presence
       "_package_paths_tmp" slist => findfiles("$(_override_dir)*");
       "_vendored_modules" slist => maplist(regex_replace("$(this)", "$(_vendored_dir)(.*).mustache", "$1", "g"), @(_vendored_paths));
       "_override_modules" slist => maplist(regex_replace("$(this)", "$(_override_dir)(.*)", "$1", "g"), @(_package_paths));
-      "_not_vendored_modules_pathname_regex" string => "$(sys.inputdir)/modules/(?!packages/vendored).*";
+      "_custom_template_modules" slist => maplist(regex_replace("$(this)", "$(_custom_template_dir)(.*).mustache", "$1", "g"), @(_custom_template_paths));
+      "_not_vendored_modules_pathname_regex" string => "$(sys.inputdir)/modules/(?!(packages/vendored|mustache/)).*";
 
   classes:
     "override_vendored_module_$(_vendored_modules)" expression => fileexists("$(_override_dir)$(_vendored_modules)");
@@ -823,6 +826,14 @@ bundle agent modules_presence
         canonify("override_vendored_module_$(_override_modules)"),
         canonify("override_module_$(_override_modules)"));
 
+    "$(sys.workdir)/modules/$(_custom_template_modules)" -> { "ENT-10793" }
+        comment => "We want to render mustache templated modules",
+        handle => "cfe_internal_update_policy_files_custom_template_modules",
+        template_method => "mustache",
+        edit_template => "$(_custom_template_dir)$(_custom_template_modules).mustache",
+        perms => u_mo("500", "root"),
+        if => fileexists("$(_custom_template_dir)$(_custom_template_modules).mustache");
+
     "$(sys.workdir)/modules"
       comment => "Copy any non-packages modules",
       handle => "cfe_internal_update_policy_files_nonpackages_modules",

modules/mustache/README.md

@@ -0,0 +1,11 @@
+Files in this directory ending in `.mustache` are rendered to
+`$(sys.workdir)/modules` (typically `/var/cfengine/modules`) using `datastate()`
+from the `update.cf` policy entry. Templates in sub-directories are not
+considered.
+
+For example `hello.sh.mustache` will be rendered to
+`$(sys.workdir)/modules/hello.sh` and `sub-dir/goodbye.sh.mustache` would not be
+rendered to `$(sys.workdir)/modules/sub-dir/goodby.sh`.
+
+## History
+- Added in 3.23.0