Add stats for queue (#4117)gh-4416

1 files changed, 19 insertions, 0 deletions

diff --git a/lib/compilation-queue.js b/lib/compilation-queue.js
index 394d89748..f8e017632 100644
--- a/lib/compilation-queue.js
+++ b/lib/compilation-queue.js
@@ -25,6 +25,22 @@
 import {executionAsyncId} from 'async_hooks';
 
 import {default as Queue} from 'p-queue';
+import PromClient from 'prom-client';
+
+// globals as essentially the compilation queue is a singleton, and if we make them members of the queue, tests fail as
+// when we create a second queue, the previous counters are still registered.
+const queueEnqueued = new PromClient.Counter({
+    name: 'ce_compilation_queue_enqueued_total',
+    help: 'Total number of jobs enqueued',
+});
+const queueDequeued = new PromClient.Counter({
+    name: 'ce_compilation_queue_dequeued_total',
+    help: 'Total number of jobs dequeued',
+});
+const queueCompleted = new PromClient.Counter({
+    name: 'ce_compilation_queue_completed_total',
+    help: 'Total number of jobs completed',
+});
 
 export class CompilationQueue {
     constructor(concurrency, timeout) {
@@ -45,7 +61,9 @@ export class CompilationQueue {
         // If we're asked to enqueue a job when we're already in a async queued job context, just run it.
         // This prevents a deadlock.
         if (this._running.has(enqueueAsyncId)) return job();
+        queueEnqueued.inc();
         return this._queue.add(() => {
+            queueDequeued.inc();
             const jobAsyncId = executionAsyncId();
             if (this._running.has(jobAsyncId)) throw new Error('somehow we entered the context twice');
             try {
@@ -53,6 +71,7 @@ export class CompilationQueue {
                 return job();
             } finally {
                 this._running.delete(jobAsyncId);
+                queueCompleted.inc();
             }
         });
     }