rename consumer folder

README.md

@@ -49,11 +49,13 @@ Therefore, in order to save the data in its transformed state, I replaced Redis
 ### What I'd add
 - a proper logging client so that logs are searchable by session_id and request_id header
 - security & rate limiting
+- database access: the server application only needs read permission
 - CI/CD
-- architecture: no need for this to be a monolithic application
+- architecture: no need for this to be a monolithic application. deploying separate resources would improve resilience, scalability, and security.
 - replace services from docker-compose with actual deployed instances
 - validate event model
 - create index on mongodb on session_id
+- currently, there is a potential problem if the websocket client tries to send the same data again. There is no uniqueness constraint on each item in the `children` array so events would be duplicated. Maybe any existing database record should be deleted or archived when a SESSION_START event arrives, or the SaveDataService should use mongo's `$unset` operator to clear the `children` array.
 
 
 

package.json

@@ -16,7 +16,7 @@
   },
   "scripts": {
     "compile": "rm -Rf ./lib && tsc",
-    "consumer:dev": "ts-node-dev src/consumers/app.ts",
+    "consumer:dev": "ts-node-dev src/consumer/app.ts",
     "lint": "eslint --ext .js,.ts src/",
     "mocha": "ts-mocha \"test/**/*.ts\" --recursive --exit",
     "server:dev": "ts-node-dev src/server/index.ts",

src/constants.json

@@ -1,7 +1,7 @@
 {
   "PORT": 8080,
   "topics": {
-    "EVENTS": "events"
+    "EVENTS": "websocket.events"
   },
   "urlPaths": {
     "websocket": "websocket"

src/consumers/services/SaveDataService.ts → src/consumer/services/SaveDataService.ts

@@ -29,7 +29,8 @@ export default class SaveDataService {
       $push: {
         children: {
           $each: data.children,
-          $sort: { 'data.timestamp': 1 }
+          // sort asc on timestamp so oldest events will be at beginning of array
+          $sort: { 'timestamp': 1 }
         }
       }
     };

test/websocket.test.ts

@@ -24,9 +24,12 @@ describe('websocket http request', () => {
   });
 
 
-  describe('sending multiple messages', () => {
-    beforeEach(done => setTimeout(done, 500));
+  describe('sending multiple messages with child events not in order', () => {
+    // give consumer app some time to receive kafka message
+    beforeEach(done => setTimeout(done, 1800));
     before(() => {
+
+      // send session_start and the last event
       clients[0].send(
         JSON.stringify([
           {
@@ -37,17 +40,23 @@ describe('websocket http request', () => {
           {
             timestamp: 1569972085,
             type: "EVENT",
-            name: "basket_removed"
+            name: "last_event"
           }
         ])
       );
 
+      // send the middle events and then session_end
       clients[0].send(
         JSON.stringify([
           {
             timestamp: 1569972083,
             type: "EVENT",
-            name: "purchase_completed"
+            name: "middle_event"
+          },
+          {
+            timestamp: 1569972083,
+            type: "EVENT",
+            name: "first_event"
           },
           {
             timestamp: 1569972086,
@@ -58,14 +67,31 @@ describe('websocket http request', () => {
       );
     });
 
-    it('saves data', async () => {
+    it('saves data with child events in order by timestamp and with start and end timestamps', async () => {
       const data = await database.findOne({session_id});
       console.log(data)
       chai.expect(data).to.have.property('session_id').which.equals(session_id);
       chai.expect(data).to.have.property('end').which.equals(1569972086);
       chai.expect(data).to.have.property('start').which.equals(1569972082);
       chai.expect(data).to.have.property('children').which.is.an('array');
-      chai.expect(data.children.length).to.equal(2);
+      chai.expect(data.children.length).to.equal(3);
+      chai.expect(data.children).to.deep.equal([
+        {
+          type: 'EVENT',
+          timestamp: 1569972083,
+          name: 'middle_event'
+        },
+        {
+          type: 'EVENT',
+          timestamp: 1569972083,
+          name: 'first_event'
+        },
+        {
+          type: 'EVENT',
+          timestamp: 1569972085,
+          name: 'last_event'
+        }
+      ])
     });
   });