Merge pull request #53 from lyft/status-endpoints

Status endpoints

.dockerignore

@@ -1,6 +1,8 @@
 .git
 .env
 node_modules
+Dockerfile
+.dockerignore
 npm-debug.log
 .storybook
 .vscode

env.js

@@ -15,6 +15,15 @@ const CORS_PROXY_PREFIX = process.env.CORS_PROXY_PREFIX || '/cors_proxy';
 const CONFIG_DIR = process.env.CONFIG_DIR || './config';
 const CONFIG_CACHE_TTL_SECONDS = process.env.CONFIG_CACHE_TTL_SECONDS || '60';
 
+// Defines a file to be required which will provide implementations for
+// any user-definable code.
+const PLUGINS_MODULE = process.env.PLUGINS_MODULE;
+
+// Optional URL which will provide information about system status. This is used
+// to show informational banners to the user.
+// If it has no protocol, it will be treated as relative to window.location.origin
+const STATUS_URL = process.env.STATUS_URL;
+
 module.exports = {
     ADMIN_API_URL,
     BASE_URL,
@@ -23,10 +32,13 @@ module.exports = {
     CONFIG_DIR,
     CORS_PROXY_PREFIX,
     NODE_ENV,
+    PLUGINS_MODULE,
+    STATUS_URL,
     processEnv: {
         ADMIN_API_URL,
         BASE_URL,
         CORS_PROXY_PREFIX,
-        NODE_ENV
+        NODE_ENV,
+        STATUS_URL
     }
 };

index.js

@@ -8,17 +8,24 @@ const fs = require('fs');
 const morgan = require('morgan');
 const express = require('express');
 const env = require('./env');
+const { applyMiddleware } = require('./plugins');
 
 const corsProxy = require('./corsProxy.js');
 
 const app = express();
 
 // Enable logging for HTTP access
 app.use(morgan('combined'));
+app.use(express.json());
 
 app.get(`${env.BASE_URL}/healthz`, (_req, res) => res.status(200).send());
 app.use(corsProxy(`${env.BASE_URL}${env.CORS_PROXY_PREFIX}`));
 
+if (typeof applyMiddleware === 'function') {
+    console.log('Found middleware plugins, applying...');
+    applyMiddleware(app);
+}
+
 if (process.env.NODE_ENV === 'production') {
     const path = require('path');
     const expressStaticGzip = require('express-static-gzip');

plugins.js

@@ -0,0 +1,11 @@
+const env = require('./env');
+
+const { middleware } = env.PLUGINS_MODULE ? require(env.PLUGINS_MODULE) : {};
+
+if (Array.isArray(middleware)) {
+    module.exports.applyMiddleware = app => middleware.forEach(m => m(app));
+} else if (middleware !== undefined) {
+    console.log(
+        `Expected middleware to be of type Array, but got ${middleware} instead`
+    );
+}

src/config/types.ts

@@ -12,4 +12,5 @@ export interface Env extends NodeJS.ProcessEnv {
     BASE_URL?: string;
     CORS_PROXY_PREFIX: string;
     DISABLE_ANALYTICS?: string;
+    STATUS_URL?: string;
 }