cleanup(sinsp/metrics): add prometheus metric and label names sanitiz…

…ation methods

Signed-off-by: Melissa Kilby <[email protected]>

userspace/libsinsp/metrics_collector.cpp

@@ -29,7 +29,6 @@ limitations under the License.
 static re2::RE2 s_libs_metrics_units_suffix_pre_prometheus_text_conversion("(_kb|_bytes|_mb|_perc|_percentage|_ratio|_ns|_ts|_sec|_total)", re2::RE2::POSIX);
 static re2::RE2 s_libs_metrics_units_memory_suffix("(_kb|_bytes)", re2::RE2::POSIX);
 static re2::RE2 s_libs_metrics_units_perc_suffix("(_perc)", re2::RE2::POSIX);
-static re2::RE2 s_libs_metrics_banned_prometheus_naming_characters("(\\.)", re2::RE2::POSIX);
 
 // For simplicity, needs to stay in sync w/ typedef enum metrics_v2_value_unit
 // https://prometheus.io/docs/practices/naming/ or https://prometheus.io/docs/practices/naming/#base-units.
@@ -91,6 +90,38 @@ std::string metric_value_to_text(const metrics_v2& metric)
 	return value_text;
 }
 
+std::string prometheus_sanitize_metric_name(const std::string& name)
+{
+	// https://prometheus.io/docs/concepts/data_model/#metric-names-and-labels
+	static const RE2 invalid_chars("[^a-zA-Z0-9_:]");
+	std::string sanitized_name = name;
+	RE2::GlobalReplace(&sanitized_name, invalid_chars, "_");
+	RE2::GlobalReplace(&sanitized_name, "_+", "_");
+	// Ensure it starts with a letter or underscore (if empty after sanitizing, set to "_")
+	if (sanitized_name.empty() || (!std::isalpha(sanitized_name.front()) && sanitized_name.front() != '_'))
+	{
+		sanitized_name = "_" + sanitized_name;
+	}
+	return sanitized_name;
+}
+
+std::string prometheus_sanitize_label_name(const std::string& name)
+	{
+	// https://prometheus.io/docs/concepts/data_model/#metric-names-and-labels
+	static const RE2 invalid_chars("[^a-zA-Z0-9_]");
+	std::string sanitized_label = name;
+	RE2::GlobalReplace(&sanitized_label, invalid_chars, "_");
+	RE2::GlobalReplace(&sanitized_label, "_+", "_");
+
+	// Ensure the label starts with a letter or underscore (if empty after sanitizing, set to "_")
+	if (sanitized_label.empty() || (!std::isalpha(sanitized_label.front()) && sanitized_label.front() != '_'))
+	{
+		sanitized_label = "_" + sanitized_label;
+	}
+
+	return sanitized_label;
+}
+
 std::string prometheus_qualifier(std::string_view prometheus_namespace, std::string_view prometheus_subsystem)
 {
 	std::string qualifier;
@@ -108,7 +139,7 @@ std::string prometheus_qualifier(std::string_view prometheus_namespace, std::str
 
 std::string prometheus_exposition_text(std::string_view metric_qualified_name, std::string_view metric_name, std::string_view metric_type_name, std::string_view metric_value, const std::map<std::string, std::string>& const_labels)
 {
-	std::string fqn(metric_qualified_name);
+	std::string fqn = prometheus_sanitize_metric_name(std::string(metric_qualified_name));
 	std::string prometheus_text = "# HELP " + fqn + " https://falco.org/docs/metrics/\n";
 	prometheus_text += "# TYPE " + fqn + " " + std::string(metric_type_name) + "\n";
 	prometheus_text += fqn;
@@ -118,14 +149,18 @@ std::string prometheus_exposition_text(std::string_view metric_qualified_name, s
 		bool first_label = true;
 		for (const auto& [key, value] : const_labels)
 		{
+			if (key.empty())
+			{
+				continue;
+			}
 			if (!first_label)
 			{
 				prometheus_text += ",";
 			} else
 			{
 				first_label = false;
 			}
-			prometheus_text += key + "=\"" + value + "\"";
+			prometheus_text += prometheus_sanitize_label_name(key) + "=\"" + value + "\"";
 		}
 		prometheus_text += "} "; // white space at the end important!
 	} else
@@ -173,7 +208,6 @@ std::string prometheus_metrics_converter::convert_metric_to_text_prometheus(cons
 	std::string prometheus_metric_name_fully_qualified = prometheus_qualifier(prometheus_namespace, prometheus_subsystem) + std::string(metric.name) + "_";
 	// Remove native libs unit suffixes if applicable.
 	RE2::GlobalReplace(&prometheus_metric_name_fully_qualified, s_libs_metrics_units_suffix_pre_prometheus_text_conversion, "");
-	RE2::GlobalReplace(&prometheus_metric_name_fully_qualified, s_libs_metrics_banned_prometheus_naming_characters, "_");
 	prometheus_metric_name_fully_qualified += std::string(metrics_unit_name_mappings_prometheus[metric.unit]);
 	return prometheus_exposition_text(prometheus_metric_name_fully_qualified,
 										metric.name,

userspace/libsinsp/test/sinsp_metrics.ut.cpp

@@ -115,12 +115,19 @@ testns_falco_memory_rss_bytes )";
 	ASSERT_EQ(metrics_names_all_str_post_unit_conversion_pre_prometheus_text_conversion,
 	"cpu_usage_ratio memory_rss_bytes memory_vsz_bytes memory_pss_bytes container_memory_used_bytes host_cpu_usage_ratio host_memory_used_bytes host_procs_running host_open_fds n_threads n_fds n_noncached_fd_lookups n_cached_fd_lookups n_failed_fd_lookups n_added_fds n_removed_fds n_stored_evts n_store_evts_drops n_retrieved_evts n_retrieve_evts_drops n_noncached_thread_lookups n_cached_thread_lookups n_failed_thread_lookups n_added_threads n_removed_threads n_drops_full_threadtable n_missing_container_images n_containers");
 
-	// Test global wrapper base metrics (pseudo metrics)
-	prometheus_text = prometheus_metrics_converter.convert_metric_to_text_prometheus("kernel_release", "testns", "falco", {{"kernel_release", "6.6.7-200.fc39.x86_64"}});
-	prometheus_text_substring = R"(# HELP testns_falco_kernel_release_info https://falco.org/docs/metrics/
-# TYPE testns_falco_kernel_release_info gauge
-testns_falco_kernel_release_info{kernel_release="6.6.7-200.fc39.x86_64"} 1
+	// Test global wrapper base metrics plus test invalid characters sanitization for the metric and label names (pseudo metrics)
+	prometheus_text = prometheus_metrics_converter.convert_metric_to_text_prometheus("56kernel_release-:!", "", "", {{"0kernel_release__", "6.6.7-200.fc39.x86_64"}, {"", "empty_key_name"}});
+	prometheus_text_substring = R"(# HELP _56kernel_release_:_info https://falco.org/docs/metrics/
+# TYPE _56kernel_release_:_info gauge
+_56kernel_release_:_info{_0kernel_release_="6.6.7-200.fc39.x86_64"} 1
 )";
+
+	prometheus_text = prometheus_metrics_converter.convert_metric_to_text_prometheus("", "", "", {{"0kernel_release__", "6.6.7-200.fc39.x86_64"}, {"", "empty_key_name"}});
+		prometheus_text_substring = R"(# HELP _info https://falco.org/docs/metrics/
+# TYPE _info gauge
+_info{_0kernel_release_="6.6.7-200.fc39.x86_64"} 1
+)";
+
 	std::cerr << prometheus_text;
 	ASSERT_TRUE(prometheus_text.find(prometheus_text_substring) != std::string::npos) << "Substring not found in prometheus_text got\n" << prometheus_text;