Watcher: fix metric stats names (#34951)

The current watcher stats metric names doesn't match the current
documentation. This commit fixes the behavior of `queued_watches`
metric, deprecates `pending_watches` metric and adds `current_watches`
to match the documented behavior. It also fixes the documentation, which
introduced `executing_watches` metric that was never added.

Fixes #34865

Author: imotov

x-pack/docs/en/rest-api/watcher/stats.asciidoc

@@ -25,7 +25,7 @@ currently being executed by {watcher}. Additional information is shared per
 watch that is currently executing. This information includes the `watch_id`,
 the time its execution started and its current execution phase.
 
-To include this metric, the `metric` option should be set to `pending_watches`
+To include this metric, the `metric` option should be set to `current_watches`
 or `_all`. In addition you can also specify the `emit_stacktraces=true`
 parameter, which adds stack traces for each watch that is being executed. These
 stack traces can give you more insight into an execution of a watch.
@@ -51,7 +51,7 @@ To include this metric, the `metric` option should include `queued_watches` or
 
 `metric`::
   (enum) Defines which additional metrics are included in the response.
-  `pending_watches`::: Includes the current executing watches in the response.
+  `current_watches`::: Includes the current executing watches in the response.
   `queued_watches`::: Includes the watches queued for execution in the response.
   `_all`::: Includes all metrics in the response.
 
@@ -98,7 +98,7 @@ and will include the basic metrics and metrics about the current executing watch
 
 [source,js]
 --------------------------------------------------
-GET _xpack/watcher/stats?metric=pending_watches
+GET _xpack/watcher/stats?metric=current_watches
 --------------------------------------------------
 // CONSOLE
 

x-pack/plugin/src/test/resources/rest-api-spec/api/xpack.watcher.stats.json

@@ -8,14 +8,14 @@
       "parts": {
         "metric": {
           "type" : "enum",
-          "options" : ["_all", "queued_watches", "pending_watches"],
+          "options" : ["_all", "queued_watches", "current_watches", "pending_watches"],
           "description" : "Controls what additional stat metrics should be include in the response"
         }
       },
       "params": {
         "metric": {
           "type" : "enum",
-          "options" : ["_all", "queued_watches", "pending_watches"],
+          "options" : ["_all", "queued_watches", "current_watches", "pending_watches"],
           "description" : "Controls what additional stat metrics should be include in the response"
         },
         "emit_stacktraces": {

x-pack/plugin/src/test/resources/rest-api-spec/test/watcher/stats/10_basic.yml

@@ -12,3 +12,55 @@
         emit_stacktraces: "true"
   - match: { "manually_stopped": false }
   - match: { "stats.0.watcher_state": "started" }
+
+---
+"Test watcher stats current watches":
+  - skip:
+      version: " - 6.5.99"
+      reason:  metrics were fixed in 6.6.0
+
+  - do:
+      xpack.watcher.stats:
+        metric: "current_watches"
+
+  - is_false: stats.0.queued_watches
+  - is_true: stats.0.current_watches
+
+---
+"Test watcher stats queued watches":
+  - skip:
+      version: " - 6.5.99"
+      reason:  metrics were fixed in 6.6.0
+
+  - do:
+      xpack.watcher.stats:
+        metric: "queued_watches"
+
+  - is_false: stats.0.current_watches
+  - is_true: stats.0.queued_watches
+
+---
+"Test watcher stats queued watches using pending_watches":
+  - skip:
+      version: " - 6.5.99"
+      reason:  metrics were fixed in 6.6.0
+      features: warnings
+
+  - do:
+      warnings:
+        - 'The pending_watches parameter is deprecated, use queued_watches instead'
+
+      xpack.watcher.stats:
+        metric: "pending_watches"
+
+  - is_false: stats.0.current_watches
+  - is_true: stats.0.queued_watches
+
+---
+"Test watcher stats all watches":
+  - do:
+      xpack.watcher.stats:
+        metric: "_all"
+
+  - is_true: stats.0.current_watches
+  - is_true: stats.0.queued_watches

x-pack/plugin/watcher/src/main/java/org/elasticsearch/xpack/watcher/rest/action/RestWatcherStatsAction.java

@@ -51,8 +51,12 @@ protected RestChannelConsumer doPrepareRequest(final RestRequest restRequest, Wa
             request.includeCurrentWatches(true);
             request.includeQueuedWatches(true);
         } else {
-            request.includeCurrentWatches(metrics.contains("queued_watches"));
-            request.includeQueuedWatches(metrics.contains("pending_watches"));
+            request.includeCurrentWatches(metrics.contains("current_watches"));
+            request.includeQueuedWatches(metrics.contains("queued_watches") || metrics.contains("pending_watches"));
+        }
+
+        if (metrics.contains("pending_watches")) {
+            deprecationLogger.deprecated("The pending_watches parameter is deprecated, use queued_watches instead");
         }