new(userspace/falco): add new static_fields config key + update schema.

Signed-off-by: Federico Di Pierro <nierro92@gmail.com>

userspace/falco/config_json_schema.h

@@ -35,6 +35,9 @@ const char config_schema_string[] = LONG_STRING_CONST(
                         "$ref": "#/definitions/AppendOutput"
                     }
                 },
+                "static_fields": {
+                    "type": "object"
+                },
                 "config_files": {
                     "type": "array",
                     "items": {

userspace/falco/configuration.cpp

@@ -663,6 +663,8 @@ void falco_configuration::load_yaml(const std::string &config_name) {
 		}
 	}
 
+	m_static_fields = m_config.get_scalar<std::map<std::string, std::string>>("static_fields", {});
+
 	std::vector<std::string> load_plugins;
 
 	bool load_plugins_node_defined = m_config.is_defined("load_plugins");

userspace/falco/configuration.h

@@ -147,6 +147,8 @@ public:
 	std::vector<rule_selection_config> m_rules_selection;
 	// Append output configuration passed by the user
 	std::vector<append_output_config> m_append_output;
+	// Static fields configuration passed by the user
+	std::map<std::string, std::string> m_static_fields;
 
 	bool m_json_output;
 	bool m_json_include_output_property;