fix: handle redis connection errors

Instead of throwing an error I've implemented retry_strategy and an interval to check if redis is (again) available. If not the service will return uncached response.

Author: SassNinja

src/hooks/redis.js

@@ -15,6 +15,11 @@ export function before(options) { // eslint-disable-line no-unused-vars
 
     return new Promise(resolve => {
       const client = hook.app.get('redisClient');
+
+      if (!client) {
+        resolve(hook);
+      }
+
       const path = parsePath(hook, options);
 
       client.get(path, (err, reply) => {
@@ -49,6 +54,11 @@ export function after(options) { // eslint-disable-line no-unused-vars
       if (!hook.result.cache.cached) {
         const duration = hook.result.cache.duration || options.defaultDuration;
         const client = hook.app.get('redisClient');
+        
+        if (!client) {
+          resolve(hook);
+        }
+
         const path = parsePath(hook, options);
 
         // adding a cache object

src/redisClient.js

@@ -1,6 +1,26 @@
 import redis from 'redis';
+import chalk from 'chalk';
 
 export default function redisClient() { // eslint-disable-line no-unused-vars
-  this.set('redisClient', redis.createClient(this.get('redis')));
+  const app = this;;
+  const cacheOptions = app.get('redisCache') || {};
+  const retryInterval = cacheOptions.retryInterval || 10000;
+  const redisOptions = Object.assign({}, this.get('redis'), {
+    retry_strategy: function (options) { // eslint-disable-line camelcase
+      app.set('redisClient', undefined);
+      if (cacheOptions.env !== 'test') {
+        console.log(`${chalk.yellow('[redis]')} not connected`);
+      }
+      return retryInterval;
+    }
+  });
+  const client = redis.createClient(redisOptions);
+
+  client.on('ready', () => {
+    app.set('redisClient', client);
+    if (cacheOptions.env !== 'test') {
+      console.log(`${chalk.green('[redis]')} connected`);
+    }
+  });
   return this;
 }

test/client.test.js

@@ -0,0 +1,33 @@
+import { expect } from 'chai';
+import RedisClient from '../src/redisClient';
+
+const app = {
+  get: function(key) {
+    return this[key];
+  },
+  set: function(key, val) {
+    this[key] = val;
+  },
+  configure: function(fn) {
+    fn.call(this);
+  }
+};
+
+describe('redisClient', () => {
+  it('should not exist if redis not connected', (done) => {
+    app.set('redis', { port: 1234 }); // force connection error
+    app.configure(RedisClient);
+    setTimeout(function () {
+      expect(app.get('redisClient')).to.not.exist;
+      done();
+    }, 500);
+  });
+  it('should be available if redis connected', (done) => {
+    app.set('redis', { port: 6379 }); // restore default
+    app.configure(RedisClient);
+    setTimeout(function () {
+      expect(app.get('redisClient')).to.exist;
+      done();
+    }, 500);
+  });
+});