Merge pull request #20 from davidsilva/video-3-load-testing-optimistic-locking

Updates made during video recording.

Author: davidsilva

README.md

@@ -1,6 +1,6 @@
 # Interview Prep
 
-[Video](https://youtu.be/e8xXtHpPZ_o)
+[Video](https://www.youtube.com/playlist?list=PL7FXjzyGAf4WDBzSv7eUO0vu8-nZV8kTr)
 
 This project grew out of wanting to prepare for an interview for a job that would have focused on Angular. As I had been using React exclusively for several months, I needed to refresh my Angular skills. Then I began to add more things to make up for my focus on AWS Amplify. The result is in some ways the opposite of what I have in my previous videos:
 
@@ -10,10 +10,12 @@ This project grew out of wanting to prepare for an interview for a job that woul
 * REST (using a NodeJS/Express backend) vs GraphQL (using Amplify and AppSync)
 * This project has nothing in regard to authentication (yet), while the Amplify project implemented authentication right at the beginning.
 * AWS infrastructure is set up and maintained using Terraform. That is obviously different from the approach AWS Amplify takes.
-* CI/CD (continuous integration/continuous deployment) workflow.
+* CI/CD (continuous integration/continuous deployment) workflow using GitHub Actions.
 
 Also, in the Amplify project I haven't yet implemented any automated testing but in this project I have unit and integration tests. I set up a GitHub Workflow with GitHub Actions to run the tests when there is a push to or a pull request on specified branches.
 
+As of February 2025, there is a load testing using k6 in the GitHub workflow.
+
 This project is Dockerized, and I developed it in a devcontainer. 
 
 ## Devcontainer
@@ -130,6 +132,7 @@ A lot of `ci.yml` is self-explanatory but here are some notes to help clarify so
   * And finally zips up everything.
 * **Update Lambda migration function**: Updates the AWS Lambda function code for database migrations using the AWS CLI. The workflow waits for the update to be completed before the function is invoked.
 * **Build and push frontend Docker image**: Note that this step uses a Dockerfile in the root of the project, rather than the Dockerfile in the frontend directory. I wanted to keep the Dockerfile in the frontend directory for local development purposes, e.g., `frontend/Dockerfile` uses the Angular server and port 4200.
+* **Load testing**: using [k6](https://k6.io/).
 
 ## Infrastructure
 
@@ -295,6 +298,7 @@ Assuming CWD is `backend`, `npx knex migrate:make <migration-file-name> --knexfi
 
 ### 0.1.3
 - Added optimistic locking. (Alternatives: Pessimistic Locking, Automatic Conflict Resolution, Eventual Consistency.)
+- Added load testing to the GitHub workflow.
 
 ### 0.1.2
 - Added Terraform configuration for managing AWS infrastructure.

backend/load-test.js

@@ -2,8 +2,8 @@ import http from 'k6/http';
 import { check, sleep } from 'k6';
 
 // Possible test types include smoke, stress, spike, soak and load.
-// Smoke: verify system can habdle a minimal load w/o issues.
-// Stress: determine breaking point by increading number of VUs until the API starts returning errors or response times degrade significantly.
+// Smoke: verify system can handle a minimal load w/o issues.
+// Stress: determine breaking point by increasing number of VUs until the API starts returning errors or response times degrade significantly.
 // Spike: test how the system handles sudden spikes in load. A sudden increase in the number of VUs to simulate a traffic spike, followed by a return to normal load.
 // Soak (endurance): test the system's stability and performance over an extended period. Running a constant load for several hours or days to identify memory leaks or performance degradation over time.
 // Load: test the system under expected peak load conditions. Running a constant load for a period of time to verify that the system can handle the expected number of users.

backend/src/__tests__/integration/products.integration.test.ts

@@ -184,8 +184,6 @@ describe('PUT /api/v0/products/:id', () => {
 
     const [createdProduct] = await db('products').insert(product).returning('*');
 
-    console.log('****** createdProduct:', createdProduct);
-
     const firstUpdate: Partial<Product> = {
       ...createdProduct,
       name: 'First Update',
@@ -195,8 +193,6 @@ describe('PUT /api/v0/products/:id', () => {
       .put(`${productsPath}/${createdProduct.id}`)
       .send(firstUpdate);
 
-    console.log('****** firstResponse:', firstResponse.body);
-
     expect(firstResponse.status).toBe(200);
 
     // Intentionally create a version mismatch