From 0e5a44d0325e51b54afa9cddba7fe00c17ed96d8 Mon Sep 17 00:00:00 2001
From: James Chartrand <jc.chartrand@gmail.com>
Date: Wed, 8 May 2024 18:40:15 -0400
Subject: [PATCH] add healthcheck

---
 healthcheck.js | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/app.js     | 21 +++++++++++++-
 src/config.js  |  2 +-
 3 files changed, 100 insertions(+), 2 deletions(-)
 create mode 100644 healthcheck.js

diff --git a/healthcheck.js b/healthcheck.js
new file mode 100644
index 0000000..e179299
--- /dev/null
+++ b/healthcheck.js
@@ -0,0 +1,79 @@
+import nodemailer from 'nodemailer'
+import axios from 'axios'
+
+const serviceURL = process.env.HEALTH_CHECK_SERVICE_URL
+const serviceName = process.env.HEALTH_CHECK_SERVICE_NAME
+const shouldPostToWebHook = process.env.HEALTH_CHECK_WEB_HOOK
+const shouldSendEmail =
+  process.env.HEALTH_CHECK_SMTP_HOST &&
+  process.env.HEALTH_CHECK_SMTP_USER &&
+  process.env.HEALTH_CHECK_SMTP_PASS &&
+  process.env.HEALTH_CHECK_EMAIL_FROM &&
+  process.env.HEALTH_CHECK_EMAIL_RECIPIENT
+
+axios
+  .get(serviceURL)
+  .then(async function (response) {
+    try {
+      const body = response.data
+      if (body.healthy === true) {
+        process.exit(0)
+      }
+      await notify(`${serviceName} is unhealthy: ${body.error}`)
+      process.exit(1)
+    } catch (error) {
+      await notify(
+        `${serviceName} is potentially unhealthy - error: ${JSON.stringify(error)}`
+      )
+      process.exit(1)
+    }
+  })
+  .catch(async (error) => {
+    await notify(
+      `${serviceName} is unhealthy and will restart after 3 tries. Error: ${error.message}`
+    )
+    process.exit(1)
+  })
+
+async function notify(message) {
+  console.log(message)
+  if (shouldSendEmail) await sendMail(message)
+  if (shouldPostToWebHook) await postToWebHook(message)
+}
+
+async function postToWebHook(text) {
+  await axios
+    .post(process.env.HEALTH_CHECK_WEB_HOOK, { text })
+    .catch((error) => {
+      console.error(error)
+    })
+}
+
+async function sendMail(message) {
+  const messageParams = {
+    from: process.env.HEALTH_CHECK_EMAIL_FROM,
+    to: process.env.HEALTH_CHECK_EMAIL_RECIPIENT,
+    subject: process.env.HEALTH_CHECK_EMAIL_SUBJECT,
+    text: message
+  }
+
+  const mailTransport = {
+    host: process.env.HEALTH_CHECK_SMTP_HOST,
+    auth: {
+      user: process.env.HEALTH_CHECK_SMTP_USER,
+      pass: process.env.HEALTH_CHECK_SMTP_PASS
+    },
+    ...(process.env.HEALTH_CHECK_SMTP_PORT && {
+      port: process.env.HEALTH_CHECK_SMTP_PORT
+    })
+  }
+
+  const transporter = nodemailer.createTransport(mailTransport)
+
+  try {
+    await transporter.sendMail(messageParams)
+  } catch (error) {
+    console.log('the email send error: ')
+    console.log(error)
+  }
+}
diff --git a/src/app.js b/src/app.js
index c145fc4..6b7899d 100644
--- a/src/app.js
+++ b/src/app.js
@@ -6,7 +6,8 @@ import errorHandler from './middleware/errorHandler.js'
 import errorLogger from './middleware/errorLogger.js'
 import invalidPathHandler from './middleware/invalidPathHandler.js'
 import verifyAuthHeader from './verifyAuthHeader.js'
-import { getConfig } from './config.js'
+import { getConfig, defaultTenantName } from './config.js'
+import { getUnsignedVC } from './test-fixtures/vc.js'
 
 function IssuingException (code, message, error = null) {
   this.code = code
@@ -27,6 +28,24 @@ export async function build (opts = {}) {
   app.use(express.urlencoded({ extended: false }))
   app.use(cors())
 
+  app.get('/healthz', async function (req, res) {
+    try {
+      const { data } = await axios.post(
+        `${req.protocol}://${req.headers.host}/instance/${defaultTenantName}/credentials/issue`,
+        getUnsignedVC()
+      )
+      if (!data.proof)
+        throw new SigningException(503, 'issuer-coordinator healthz failed')
+    } catch (e) {
+      console.log(`exception in healthz: ${JSON.stringify(e)}`)
+      return res.status(503).json({
+        error: `issuer-coordinator healthz check failed with error: ${e}`,
+        healthy: false
+      })
+    }
+    res.send({ message: 'issuer-coordinator server status: ok.', healthy: true })
+  })
+
   app.get('/', async function (req, res, next) {
     if (enableStatusService) {
       try {
diff --git a/src/config.js b/src/config.js
index 62fe589..bc77880 100644
--- a/src/config.js
+++ b/src/config.js
@@ -1,6 +1,6 @@
 let CONFIG
 const defaultPort = 4005
-const defaultTenantName = 'test'
+export const defaultTenantName = 'test'
 const demoTenantName = 'testing'
 const randomTenantName = 'random'
 const randtomTenantToken = 'UNPROTECTED'