BF: Handle redis errors

Fix #9

This commit offers a cleanup to unify the redis client usage
and add an error handler to handle redis connection errors. The option
for offline queue has been removed (for now) as it may grow the callback
queue to infinity and eventually result in a RangeError.

lib/UtapiClient.js

@@ -1,4 +1,3 @@
-import Redis from 'ioredis';
 import { Logger } from 'werelogs';
 import Datastore from './Datastore';
 import { createBucket, deleteBucket, listBucket, getBucketAcl, putBucketAcl,
@@ -9,27 +8,26 @@ import { createBucket, deleteBucket, listBucket, getBucketAcl, putBucketAcl,
     deleteObject, bucketOutgoingBytes, getObject, getObjectAcl, putObjectAcl,
     putObject, uploadPart,
 } from './schema';
+import redisClient from '../utils/redisClient';
 
 export default class UtapiClient {
     constructor(config) {
         this.disableClient = true;
-        if (config) {
-            const { redis } = config;
-            if (redis) {
-                // when redis server is unavailable, commands are added to an
-                // offline queue and processed when redis is back again
-                // TODO: need to revisit this. It needs to be verified if this
-                // option is hogging memory under heavy load when redis is
-                // unavailable
-                redis.enableOfflineQueue = true;
-                // keep alive 3 seconds
-                redis.keepAlive = 3000;
-                const redisClient = new Redis(redis);
-                this.ds = new Datastore().setClient(redisClient);
-                this.disableClient = false;
-                this.log = new Logger('UtapiClient',
-                    config.log || { level: 'info', dump: 'error' });
-            }
+        this.log = null;
+        this.ds = null;
+        // setup logger
+        if (config && config.log) {
+            this.log = new Logger('UtapiClient', { level: config.log.level,
+                    dump: config.log.dumpLevel });
+        } else {
+            this.log = new Logger('UtapiClient', { level: 'info',
+                dump: 'error' });
+        }
+        // setup datastore
+        if (config && config.redis) {
+            this.ds = new Datastore()
+                .setClient(redisClient(config.redis, this.log));
+            this.disableClient = false;
         }
     }
 

lib/server.js

@@ -1,6 +1,5 @@
 import http from 'http';
 import https from 'https';
-import Redis from 'ioredis';
 
 import { Clustering, https as arsenal } from 'arsenal';
 import { Logger } from 'werelogs';
@@ -11,6 +10,7 @@ import Route from '../router/Route';
 import Router from '../router/Router';
 import UtapiRequest from '../lib/UtapiRequest';
 import Datastore from './Datastore';
+import redisClient from '../utils/redisClient';
 
 class UtapiServer {
     /**
@@ -178,23 +178,11 @@ export default function spawn(params) {
     } else {
         port = Config.port;
     }
-    // when redis server is unavailable, commands are added to an offline queue
-    // and processed when redis is back again
-    // TODO: need to revisit this. It needs to be verified if this option
-    // is hogging memory under heavy load when redis is unavailable
-    redis.enableOfflineQueue = true;
-    // keep alive 3 seconds
-    redis.keepAlive = 3000;
     const logger = new Logger('Utapi', { level: log.logLevel,
         dump: log.dumpLevel });
     const cluster = new Clustering(workers, logger);
     cluster.start(worker => {
-        const redisClient = new Redis(redis);
-        const datastore = new Datastore().setClient(redisClient);
-
-        redisClient.on('error', err => logger.trace('error with redis client', {
-            error: err,
-        }));
+        const datastore = new Datastore().setClient(redisClient(redis, logger));
         const server = new UtapiServer(worker, port, datastore, logger);
         server.startup();
     });

utils/redisClient.js

@@ -0,0 +1,20 @@
+import Redis from 'ioredis';
+
+/**
+* Creates a new Redis client instance
+* @param {object} config - redis configuration
+* @param {Werelogs} log - Werelogs logger
+* @return {Redis} - Redis client instance
+*/
+export default function redisClient(config, log) {
+    const redisClient = new Redis(Object.assign({
+        // disable offline queue
+        enableOfflineQueue: false,
+        // keep alive 3 seconds
+        keepAlive: 3000,
+    }, config));
+    redisClient.on('error', err => log.trace('error with redis client', {
+        error: err,
+    }));
+    return redisClient;
+}