Merge branch 'sushantdhiman-fix-evict'

README.md

@@ -141,7 +141,7 @@ An optional object/dictionary with the any of the following properties:
 - `fifo` : if true the oldest resources will be first to be allocated. If false the most recently released resources will be the first to be allocated. This in effect turns the pool's behaviour from a queue into a stack. `boolean`, (default true)
 - `priorityRange`: int between 1 and x - if set, borrowers can specify their relative priority in the queue if no resources are available.
                          see example.  (default 1)
-- `autostart`: boolean, should the pool start creating resources etc once the constructor is called, (default true)
+- `autostart`: boolean, should the pool start creating resources, initialize the evictor, etc once the constructor is called. If false, the pool can be started by calling `pool.start`, otherwise the first call to `acquire` will start the pool. (default true)
 - `evictionRunIntervalMillis`: How often to run eviction checks. Default: 0 (does not run).
 - `numTestsPerRun`: Number of resources to check each eviction run.  Default: 3.
 - `softIdleTimeoutMillis`: amount of time an object may sit idle in the pool before it is eligible for eviction by the idle object evictor (if any), with the extra condition that at least "min idle" object instances remain in the pool. Default -1 (nothing can get evicted)
@@ -219,6 +219,14 @@ The pool is an event emitter. Below are the events it emits and any args for tho
 - `factoryDestroyError` : emitted when a promise returned by `factory.destroy` is rejected. If this event has no listeners then the `error` will be silently discarded
   - `error`: whatever `reason` the promise was rejected with.
 
+### pool.start
+
+```js
+pool.start()
+```
+
+If `autostart` is `false` then this method can be used to start the pool and therefore begin creation of resources, start the evictor, and any other internal logic.
+
 ## Idle Object Eviction
 
 The pool has an evictor (off by default) which will inspect idle items in the pool and `destroy` them if they are too old.

lib/Pool.js

@@ -392,6 +392,10 @@ class Pool extends EventEmitter {
    * @returns {Promise}
    */
   acquire (priority) {
+    if (this._started === false && this._config.autostart === false) {
+      this.start()
+    }
+
     if (this._draining) {
       return this._Promise.reject(new Error('pool is draining and cannot accept work'))
     }

test/generic-pool-test.js

@@ -667,3 +667,29 @@ tap.test('destroy should redispense', function (t) {
   })
   .catch(t.threw)
 })
+
+tap.test('evictor start with acquire when autostart is false', function (t) {
+  const pool = createPool({
+    create: function () {
+      return Promise.resolve({ id: 'validId' })
+    },
+    validate: function (resource) {
+      return Promise.resolve(true)
+    },
+    destroy: function (client) {}
+  }, {
+    evictionRunIntervalMillis: 10000,
+    autostart: false
+  })
+
+  t.equal(pool._scheduledEviction, null)
+
+  pool.acquire()
+  .then(function (obj) {
+    t.notEqual(pool._scheduledEviction, null)
+    pool.release(obj)
+    utils.stopPool(pool)
+    t.end()
+  })
+  .catch(t.threw)
+})