mod_http_admin_api: Ensure freshness of metrics when in manual mode
When in manual collection mode, as recommended for Prometheus,
collection needs to be triggered manually, or they would be stale,
possibly dating from the start of the server. This might vary per metric
depending on how and when the metrics are gathered.
--- a/mod_http_admin_api/mod_http_admin_api.lua Thu Nov 18 09:07:40 2021 +0000
+++ b/mod_http_admin_api/mod_http_admin_api.lua Thu Nov 18 19:26:07 2021 +0100
@@ -17,6 +17,8 @@
local site_name = module:get_option_string("site_name", module.host);
+local manual_stats_collection = module:context("*"):get_option("statistics_interval") == "manual";
+
local json_content_type = "application/json";
local www_authenticate_header = ("Bearer realm=%q"):format(module.host.."/"..module.name);
@@ -612,6 +614,9 @@
local function get_server_metrics(event)
event.response.headers["Content-Type"] = json_content_type;
local result = {};
+ if manual_stats_collection then
+ statsmanager.collect();
+ end
local families = statsmanager.get_metric_registry():get_metric_families();
result.memory = maybe_export_plain_gauge(families.process_resident_memory_bytes);
result.cpu = maybe_export_plain_counter(families.process_cpu_seconds);