From 0d9ad99e3d014a1609df230327637a4b1aa31b6d Mon Sep 17 00:00:00 2001
From: Mithun Kamath <callmekatootie@gmail.com>
Date: Thu, 28 May 2020 11:35:48 +0530
Subject: [PATCH] Add /health endpoint for health check

---
 src/common/errors.js             |  3 ++-
 src/modules/health/controller.js | 11 +++++++++++
 src/modules/health/route.js      | 12 ++++++++++++
 src/modules/health/service.js    | 17 +++++++++++++++++
 4 files changed, 42 insertions(+), 1 deletion(-)
 create mode 100644 src/modules/health/controller.js
 create mode 100644 src/modules/health/route.js
 create mode 100644 src/modules/health/service.js

diff --git a/src/common/errors.js b/src/common/errors.js
index d1fd740..546ccee 100644
--- a/src/common/errors.js
+++ b/src/common/errors.js
@@ -21,5 +21,6 @@ module.exports = {
   newEntityNotFoundError: msg => new AppError(404, msg || 'The entity does not exist.'),
   newAuthError: msg => new AppError(401, msg || 'Auth failed.'),
   newPermissionError: msg => new AppError(403, msg || 'The entity does not exist.'),
-  newConflictError: msg => new AppError(409, msg || 'The entity does not exist.')
+  newConflictError: msg => new AppError(409, msg || 'The entity does not exist.'),
+  serviceUnavailableError: msg => new AppError(503, msg || 'One or more services are not available')
 }
diff --git a/src/modules/health/controller.js b/src/modules/health/controller.js
new file mode 100644
index 0000000..cfd94c2
--- /dev/null
+++ b/src/modules/health/controller.js
@@ -0,0 +1,11 @@
+/**
+ * the role controller
+ */
+
+const service = require('./service')
+const helper = require('../../common/helper')
+const methods = helper.getControllerMethods(service)
+
+module.exports = {
+  ...methods
+}
diff --git a/src/modules/health/route.js b/src/modules/health/route.js
new file mode 100644
index 0000000..1189977
--- /dev/null
+++ b/src/modules/health/route.js
@@ -0,0 +1,12 @@
+/**
+ * the health routes
+ */
+
+const Controller = require('./controller')
+module.exports = {
+  '/health': {
+    get: {
+      method: Controller.get
+    }
+  }
+}
diff --git a/src/modules/health/service.js b/src/modules/health/service.js
new file mode 100644
index 0000000..d1cf1fe
--- /dev/null
+++ b/src/modules/health/service.js
@@ -0,0 +1,17 @@
+const errors = require('../../common/errors')
+const models = require('../../models')
+
+async function get () {
+  // Check QLDB Connection by retrieving a session
+  try {
+    const session = await models.DBHelper.getSession()
+
+    session.close()
+  } catch (e) {
+    throw errors.serviceUnavailableError(`QLDB is unavailable, ${e.message}`)
+  }
+
+  return { checksRun: 1 }
+}
+
+module.exports = { get }