Merge pull request #7632 from Icinga/feature/dsl-get-templates

DSL: Add get_template{,s}

doc/18-library-reference.md

@@ -908,6 +908,58 @@ function get_objects(type);
 Returns an array of objects whose type matches the specified type. `type` must refer
 to a type object.
 
+### get_template <a id="objref-get_template"></a>
+
+Signature:
+
+```
+function get_template(type, name);
+```
+
+Returns the template with the specified type and name, or `null` if no such object exists. `type` must refer
+to a type object.
+
+> **Note**
+>
+> Only the name and debug info attributes are available for templates accessed in the DSL.
+> Object attributes are not available in this scope.
+
+You can use this functionality to check whether a template exists e.g. on a satellite endpoint
+and if not, import a different template.
+
+```
+object Host "icinga-agent47.localdomain" {
+  if (get_template(Host, "master-host-tmpl")) {
+    import "master-host-tmpl"
+  } else {
+    import "generic-host"
+  }
+}
+```
+
+### get_templates <a id="objref-get_templates"></a>
+
+Signature:
+
+```
+function get_templates(type);
+```
+
+Returns an array of templates whose type matches the specified type. `type` must refer
+to a type object.
+
+> **Note**
+>
+> Only the name and debug info attributes are available for templates accessed in the DSL.
+> Object attributes are not available in this scope.
+
+You can use this function to iterate over all available template names, similar to what
+the [templates API URL endpoint](12-icinga2-api.md#icinga2-api-config-templates) provides.
+
+```
+<1> => get_templates(Host).map(n => n.name)
+[ "ssh-agent" ]
+```
 
 ## Math object <a id="math-object"></a>
 

lib/base/scriptutils.cpp

@@ -14,6 +14,7 @@
 #include "base/dependencygraph.hpp"
 #include "base/initialize.hpp"
 #include "base/namespace.hpp"
+#include "config/configitem.hpp"
 #include <boost/regex.hpp>
 #include <algorithm>
 #include <set>
@@ -35,6 +36,8 @@ REGISTER_FUNCTION(System, exit, &Application::Exit, "status");
 REGISTER_SAFE_FUNCTION(System, typeof, &ScriptUtils::TypeOf, "value");
 REGISTER_SAFE_FUNCTION(System, keys, &ScriptUtils::Keys, "value");
 REGISTER_SAFE_FUNCTION(System, random, &Utility::Random, "");
+REGISTER_SAFE_FUNCTION(System, get_template, &ScriptUtils::GetTemplate, "type:name");
+REGISTER_SAFE_FUNCTION(System, get_templates, &ScriptUtils::GetTemplates, "type");
 REGISTER_SAFE_FUNCTION(System, get_object, &ScriptUtils::GetObject, "type:name");
 REGISTER_SAFE_FUNCTION(System, get_objects, &ScriptUtils::GetObjects, "type");
 REGISTER_FUNCTION(System, assert, &ScriptUtils::Assert, "value");
@@ -407,6 +410,57 @@ Array::Ptr ScriptUtils::Keys(const Object::Ptr& obj)
 	return new Array(std::move(result));
 }
 
+static Dictionary::Ptr GetTargetForTemplate(const ConfigItem::Ptr& item)
+{
+	DebugInfo di = item->GetDebugInfo();
+
+	return new Dictionary({
+		{ "name", item->GetName() },
+		{ "type", item->GetType()->GetName() },
+		{ "location", new Dictionary({
+			{ "path", di.Path },
+			{ "first_line", di.FirstLine },
+			{ "first_column", di.FirstColumn },
+			{ "last_line", di.LastLine },
+			{ "last_column", di.LastColumn }
+		}) }
+	});
+}
+
+Dictionary::Ptr ScriptUtils::GetTemplate(const Value& vtype, const String& name)
+{
+	Type::Ptr ptype;
+
+	if (vtype.IsObjectType<Type>())
+		ptype = vtype;
+	else
+		ptype = Type::GetByName(vtype);
+
+	ConfigItem::Ptr item = ConfigItem::GetByTypeAndName(ptype, name);
+
+	if (!item || !item->IsAbstract())
+		return nullptr;
+
+	DebugInfo di = item->GetDebugInfo();
+
+	return GetTargetForTemplate(item);
+}
+
+Array::Ptr ScriptUtils::GetTemplates(const Type::Ptr& type)
+{
+	if (!type)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("Invalid type: Must not be null"));
+
+	ArrayData result;
+
+	for (const ConfigItem::Ptr& item : ConfigItem::GetItems(type)) {
+		if (item->IsAbstract())
+			result.push_back(GetTargetForTemplate(item));
+	}
+
+	return new Array(std::move(result));
+}
+
 ConfigObject::Ptr ScriptUtils::GetObject(const Value& vtype, const String& name)
 {
 	Type::Ptr ptype;

lib/base/scriptutils.hpp

@@ -33,6 +33,8 @@ public:
 	static Array::Ptr Range(const std::vector<Value>& arguments);
 	static Type::Ptr TypeOf(const Value& value);
 	static Array::Ptr Keys(const Object::Ptr& obj);
+	static Dictionary::Ptr GetTemplate(const Value& vtype, const String& name);
+	static Array::Ptr GetTemplates(const Type::Ptr& type);
 	static ConfigObject::Ptr GetObject(const Value& type, const String& name);
 	static Array::Ptr GetObjects(const Type::Ptr& type);
 	static void Assert(const Value& arg);