feat(metrics): add optional k8s metadata labels to rules_matches

Signed-off-by: Debasish-87 <22btics06@suiit.ac.in>

Author: Debasish-87

userspace/falco/config_json_schema.h

@@ -577,6 +577,10 @@ const char config_schema_string[] = LONG_STRING_CONST(
                 },
                 "jemalloc_stats_enabled": {
                     "type": "boolean"
+                },
+                "include_k8s_metadata": {
+                    "type": "boolean",
+                    "default": false
                 }
             },
             "minProperties": 1,

userspace/falco/configuration.cpp

@@ -96,6 +96,7 @@ falco_configuration::falco_configuration():
         m_metrics_flags(0),
         m_metrics_convert_memory_to_mb(true),
         m_metrics_include_empty_values(false),
+        m_include_k8s_metadata(false),
         m_plugins_hostinfo(true),
         m_capture_enabled(false),
         m_capture_path_prefix("/tmp/falco"),
@@ -563,6 +564,7 @@ void falco_configuration::load_yaml(const std::string &config_name) {
 	m_base_syscalls_all = m_config.get_scalar<bool>("base_syscalls.all", false);
 
 	m_metrics_enabled = m_config.get_scalar<bool>("metrics.enabled", false);
+	m_include_k8s_metadata = m_config.get_scalar<bool>("metrics.include_k8s_metadata", false);
 	m_metrics_interval_str = m_config.get_scalar<std::string>("metrics.interval", "5000");
 	m_metrics_interval = falco::utils::parse_prometheus_interval(m_metrics_interval_str);
 	m_metrics_stats_rule_enabled = m_config.get_scalar<bool>("metrics.output_rule", false);

userspace/falco/configuration.h

@@ -190,6 +190,7 @@ class falco_configuration {
 	uint32_t m_metrics_flags;
 	bool m_metrics_convert_memory_to_mb;
 	bool m_metrics_include_empty_values;
+	bool m_include_k8s_metadata;
 	std::vector<plugin_config> m_plugins;
 	bool m_plugins_hostinfo;
 

userspace/falco/falco_metrics.cpp

@@ -206,6 +206,12 @@ std::string falco_metrics::falco_to_text_prometheus(
 				        {"priority", std::to_string(rule->priority)},
 				        {"source", rule->source},
 				};
+				if(state.config->m_include_k8s_metadata) {
+					// Kubernetes metadata is not available at metrics aggregation level.
+					// Expose placeholder labels for consistency with other Falco outputs.
+					const_labels["k8s_ns_name"] = "n/a";
+					const_labels["k8s_pod_name"] = "n/a";
+				}
 				std::for_each(rule->tags.cbegin(),
 				              rule->tags.cend(),
 				              [&const_labels](std::string const& tag) {