Improve error handling (#100)

* Improve connection errors handling after startup

* Remove error event listener after initial connection

* Do not return the client if `lazyConnect` is falsy

* Refactor and allow for reconnection attempts

* Call `onEnd` directly without emitting `end` event

Author: MSE99

index.js

@@ -65,12 +65,44 @@ function fastifyRedis (fastify, options, next) {
   }
 
   if (!redisOptions.lazyConnect) {
-    return client.info((err, _) => {
-      return err ? next(err) : next()
-    })
-  } else {
-    next()
+    const onEnd = function (err) {
+      client
+        .off('ready', onReady)
+        .off('error', onError)
+        .off('end', onEnd)
+        .quit(() => next(err))
+    }
+
+    const onReady = function () {
+      client
+        .off('end', onEnd)
+        .off('error', onError)
+        .off('ready', onReady)
+
+      next()
+    }
+
+    const onError = function (err) {
+      // Swallow network errors to allow ioredis
+      // to preform reconnection and emit 'end'
+      // event if reconnection eventually
+      // fails.
+      // Any other errors during startup will
+      // trigger the 'end' event.
+      if (err instanceof Redis.ReplyError) {
+        onEnd(err)
+      }
+    }
+
+    client
+      .on('end', onEnd)
+      .on('error', onError)
+      .on('ready', onReady)
+
+    return
   }
+
+  next()
 }
 
 function close (fastify, done) {

test/test.js

@@ -74,6 +74,15 @@ test('fastify.redis should support url', (t) => {
       })
       this.quit = () => {}
       this.info = cb => cb(null, 'info')
+      this.on = function (name, handler) {
+        if (name === 'ready') {
+          handler(null, 'ready')
+        }
+
+        return this
+      }
+      this.off = function () { return this }
+
       return this
     }
   })
@@ -377,7 +386,7 @@ test('Should not throw within different contexts', (t) => {
 })
 
 test('Should throw when trying to connect on an invalid host', (t) => {
-  t.plan(2)
+  t.plan(1)
 
   const fastify = Fastify({ pluginTimeout: 20000 })
   t.teardown(() => fastify.close())
@@ -388,8 +397,7 @@ test('Should throw when trying to connect on an invalid host', (t) => {
     })
 
   fastify.ready((err) => {
-    t.type(err, 'MaxRetriesPerRequestError')
-    t.equal(err.message, 'Reached the max retries per request limit (which is 20). Refer to "maxRetriesPerRequest" option for details.')
+    t.ok(err)
   })
 })