📖 document exposed metrics

Update documentation for the metrics package to enumerate all exposed
metrics with an explanation of what they capture.

Author: djzager

pkg/metrics/doc.go

@@ -15,6 +15,51 @@ limitations under the License.
 */
 
 /*
-Package metrics contains controller related metrics utilities
+Package metrics contains controller related metrics utilities.
+
+Client Metrics
+
+"rest_client_request_latency_seconds" - Request latency in seconds. Broken down by verb and URL.
+
+"rest_client_requests_total" - Number of HTTP requests, partitioned by status code, method, and host.
+
+Reflector Metrics
+
+"reflector_lists_total" - Total number of API lists done by the reflectors.
+
+"reflector_list_duration_seconds" - How long an API list takes to return and decode for the reflectors.
+
+"reflector_items_per_list" - How many items an API list returns to the reflectors.
+
+"reflector_watches_total" - Total number of API watches done by the reflectors.
+
+"reflector_short_watches_total" - Total number of short API watches done by the reflectors.
+
+"reflector_watch_duration_seconds" - How long an API watch takes to return and decode for the reflectors.
+
+"reflector_items_per_watch" - How many items an API watch returns to the reflectors.
+
+"reflector_last_resource_version" - Last resource version seen for the reflectors.
+
+Workqueue Metrics
+
+"workqueue_depth" - Current depth of workqueue
+
+"workqueue_adds_total" - Total number of adds handled by workqueue.
+
+"workqueue_queue_duration_seconds" - How long in seconds an item stays in workqueue before being requested.
+
+"workqueue_work_duration_seconds" - How long in seconds processing an item from workqueue takes.
+
+"workqueue_unfinished_work_seconds" - How many seconds of work has done that 
+is in progress and hasn't been observed by work_duration. Large 
+values indicate stuck threads. One can deduce the number of stuck
+threads by observing the rate at which this increases.
+
+"workqueue_longest_running_processor_seconds" - How many seconds has the longest running 
+processor for workqueue been running.
+
+"workqueue_retries_total" - Total number of retries handled by workqueue.
+
 */
 package metrics