adding multi proxy load balancer example

Author: Rolando Santamaria Maso

demos/load-balancer-multiple-proxies.js

@@ -0,0 +1,38 @@
+'use strict'
+
+const gateway = require('../index')
+const { P2cBalancer } = require('load-balancers')
+const lambdaProxy = require('http-lambda-proxy')
+
+// @TODO: update the list of target origins or proxy instances
+const targets = [
+  'http://localhost:3000',
+  lambdaProxy({
+    target: process.env.FUNCTION_NAME,
+    region: process.env.AWS_REGION
+  })
+]
+const balancer = new P2cBalancer(targets.length)
+
+gateway({
+  routes: [{
+    proxyHandler: (req, res, url, proxy, proxyOpts) => {
+      const target = targets[balancer.pick()]
+      if (typeof target === 'string') {
+        proxyOpts.base = target
+      } else {
+        proxy = target
+      }
+
+      return proxy(req, res, url, proxyOpts)
+    },
+    prefix: '/balanced'
+  }]
+}).start(8080).then(() => console.log('API Gateway listening on 8080 port!'))
+
+const service = require('restana')({})
+service
+  .get('/get', (req, res) => res.send({ msg: 'Hello from service 1!' }))
+  .start(3000).then(() => console.log('Public service listening on 3000 port!'))
+
+// Usage: curl 'http://localhost:8080/balanced/get'