add healthz endpoint and test

src/app.js

@@ -10,7 +10,8 @@ import verifyAuthHeader from './verifyAuthHeader.js'
 import { getConfig } from './config.js'
 import testVC from './testVC.js';
 import CoordinatorException from './CoordinatorException.js';
-import { getSignedDIDAuth, verifyDIDAuth } from './didAuth.js';
+import { getSignedDIDAuth } from './didAuth.js';
+import { getDataForExchangeSetupPost } from './test-fixtures/vc.js';
 
 async function callService(endpoint, body) {
 
@@ -33,6 +34,41 @@ export async function build(opts = {}) {
     app.use(express.urlencoded({ extended: false }));
     app.use(cors())
 
+    app.get('/healthz', async function(req, res) {
+        const baseURL = `${req.protocol}://${req.headers.host}`
+        const testData = getDataForExchangeSetupPost('test')
+        const exchangeURL = `${baseURL}/exchange/setup`
+        try {
+          const response = await axios.post(exchangeURL, testData)
+          const { data: walletQuerys } = response
+          const walletQuery = walletQuerys.find((q) => q.retrievalId === 'someId')
+          const parsedDeepLink = new URL(walletQuery.directDeepLink)
+          const requestURI = parsedDeepLink.searchParams.get('vc_request_url')
+          const challenge = parsedDeepLink.searchParams.get('challenge')
+          const didAuth = await getSignedDIDAuth('did:ex:223234', challenge)
+          const { data: vc } = await axios.post(requestURI, didAuth)
+
+          if (
+            !vc.proof
+          ) {
+            throw new TransactionException(
+              503,
+              'transaction-service healthz failed'
+            )
+          }
+        } catch (e) {
+          console.log(`exception in healthz: ${JSON.stringify(e)}`)
+          return res.status(503).json({
+            error: `transaction-service healthz check failed with error: ${e}`,
+            healthy: false
+          })
+        }
+        res.send({
+          message: 'transaction-service server status: ok.',
+          healthy: true
+        })
+    })
+
     app.get('/', async function (req, res, next) {
         if (enableStatusService) {
             try {

src/app.test.js

@@ -327,4 +327,28 @@ describe('api', () => {
   })
 
 
+  describe('GET /healthz', function () {
+    it.only('returns 200 if healthy', async function () {
+      const response = await request(app).get('/healthz')
+
+      expect(response.header['content-type']).to.have.string('json')
+      expect(response.status).to.eql(200)
+      expect(response.body).to.eql({
+        message: 'transaction-service server status: ok.',
+        healthy: true
+      })
+    })
+
+    it('returns 503 if not healthy', async function () {
+      // we delete the keyv store to force an error
+      //clearKeyv()
+      const response = await request(app).get('/healthz')
+
+      expect(response.header['content-type']).to.have.string('json')
+      expect(response.status).to.eql(503)
+      expect(response.body).to.have.property('healthy', false)
+      initializeTransactionManager()
+    })
+  })
+
 })