Expose queue depth and pending resources in stats

lib/Pool.js

@@ -74,8 +74,8 @@ module.exports = class Pool extends EventEmitter {
  }
 
  stats() {
- const { size, idle, acquired, bad, pending, available } = this._resourceStore;
- return { size, idle, acquired, bad, available, pending };
+ const { size, idle, pending, acquired, bad, available } = this._resourceStore;
+ return { size, idle, queued: this._acquireQueue.length, pending, acquired, bad, available };
  }
 
  async shutdown() {
@@ -154,7 +154,7 @@ module.exports = class Pool extends EventEmitter {
  }
 
  _checkAcquireQueue() {
- debug('[%d] Checking acquire queue', getContextId());
+ debug('[%d] Checking acquire queue (%d)', getContextId(), this._acquireQueue.length);
  if (this._acquireQueue.length === 0) return debug('[%d] Acquire queue is empty', getContextId());
  if (this._resourceStore.isExhausted()) return debug('[%d] Pool is exhausted', getContextId());
  const { resolve } = this._acquireQueue.shift();

test/Pool.test.js

@@ -621,9 +621,11 @@ describe('Pool', () => {
  const factory = new TestFactory();
  const pool = createPool({ factory });
 
- const { size, idle, acquired, bad, available } = pool.stats();
+ const { size, idle, queued, pending, acquired, bad, available } = pool.stats();
  eq(size, 0);
  eq(idle, 0);
+ eq(queued, 0);
+ eq(pending, 0);
  eq(acquired, 0);
  eq(bad, 0);
  eq(available, Infinity);
@@ -660,6 +662,22 @@ describe('Pool', () => {
  eq(available, Infinity);
  });
 
+ it('should report stats for a pool with queued acquisition requests', async () => {
+ const resources = ['R1'];
+ const factory = new TestFactory(resources);
+ const pool = createPool({ factory, maxSize: 1 });
+
+ await pool.acquire();
+ pool.acquire();
+ pool.acquire();
+
+ const { size, idle, queued, acquired } = pool.stats();
+ eq(size, 1);
+ eq(idle, 0);
+ eq(queued, 2);
+ eq(acquired, 1);
+ });
+
  it('should report stats for a pool with bad resources', async (t, done) => {
  const resources = ['R1', { destroyError: 'Oh Noes!', value: 'R2' }, 'R3'];
  const factory = new TestFactory(resources);