create health check endpoint for mongodb

README.md

@@ -48,6 +48,8 @@ npm run lint
 - GET /users/settings - gets the current user's setup
 - GET /users/accessToken - gets the user's access token
 
+- GET /health - gets the app health
+
 ## Configuration
 
 please see [configuration.md](configuration.md).

configuration.md

@@ -31,6 +31,7 @@ The following config parameters are supported, they are defined in `src/config.j
 |TOPCODER_AUTH_SECRET| The auth secret used to sign the JWT| No default - needs to be set up|
 |TOPCODER_VALID_ISSUERS| Stringified array of valid JWT issuers| `'["topcoder-dev.com"]'`|
 |TOPCODER_JWT_KEY_CACHE_TIME| They JWT cache time | 90 |
+|MONGODB_TIMEOUT | The timeout used to check if the app is healthy. |10000 |
 
 ## GitHub OAuth App Setup
 

src/common/errors.js

@@ -53,11 +53,19 @@ class ForbiddenError extends ApiError {
     this.details = details;
   }
 }
+// The forbidden error
+class ServiceUnavailable extends ApiError {
+  constructor(message, details) {
+    super(503, 'SERVICE_UNAVAILABLE', message);
+    this.details = details;
+  }
+}
 
 module.exports = {
   ApiError,
   ValidationError,
   NotFoundError,
   UnauthorizedError,
   ForbiddenError,
+  ServiceUnavailable,
 };

src/config.js

@@ -13,6 +13,7 @@ module.exports = {
   API_VERSION: process.env.API_VERSION || 'v1',
   LOG_LEVEL: process.env.LOG_LEVEL || 'info',
   MONGODB_URI: process.env.MONGODB_URI || 'mongodb://localhost:27017/topcoderx',
+  MONGODB_TIMEOUT: process.env.MONGODB_TIMEOUT || 10000, // eslint-disable-line no-magic-numbers
   SESSION_SECRET: process.env.SESSION_SECRET || 'kjsdfkj34857',
   // Github and gitlab client id and secret
   GITHUB_CLIENT_ID: process.env.GITHUB_CLIENT_ID || 'ae39bea2a2a23f1dd032',

src/controllers/AppHealthController.js

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2019 TopCoder, Inc. All rights reserved.
+ */
+
+/**
+ * This controller exposes application health related endpoints.
+ *
+ * @author Thomas Kranitsas
+ * @version 1.0
+ */
+const helper = require('../common/helper');
+const AppHealthService = require('../services/AppHealthService');
+
+/**
+ * gets the application health
+ * @returns {Object} the health details
+ */
+async function getAppHealth() {
+  return await AppHealthService.getAppHealth();
+}
+
+module.exports = {
+  getAppHealth,
+};
+
+helper.buildController(module.exports);

src/routes.js

@@ -208,4 +208,10 @@ module.exports = {
       method: 'getAppConfig',
     },
   },
+  '/health': {
+    get: {
+      controller: 'AppHealthController',
+      method: 'getAppHealth',
+    },
+  },
 };

src/services/AppHealthService.js

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2019 TopCoder, Inc. All rights reserved.
+ */
+
+/**
+ * This service will provide app health related operations.
+ *
+ * @author Thomas Kranitsas
+ * @version 1.0
+ */
+const config = require('../config');
+const helper = require('../common/helper');
+const errors = require('../common/errors');
+const User = require('../models').User;
+
+/**
+ * gets the application health
+ * @returns {Object} the health details
+ */
+async function getAppHealth() {
+  const checkMongoDB = new Promise((resolve, reject) => {
+    User.findOne({}, (err, data) => {
+      if (err) {
+        return reject(new errors.ServiceUnavailable('MongoDB instance cannot be reached'));
+      }
+      return resolve();
+    });
+  });
+
+  const timeOutBreak = new Promise((resolve, reject) => {
+    setTimeout(reject, config.MONGODB_TIMEOUT, new errors.ServiceUnavailable('MongoDB instance cannot be reached'));
+  });
+
+  await Promise.race([checkMongoDB, timeOutBreak]);
+
+  return {
+    checksRun: 1,
+  };
+}
+
+module.exports = {
+  getAppHealth,
+};
+
+helper.buildService(module.exports);