Task 9 Solution

[maksumov]

Task 9 Definition

Task defined at https://github.com/rolling-scopes-school/nodejs-aws-tasks/blob/main/task9-bff/task.md

Task 9.1

• [x] A working and correct express application should be in the bff-service folder. Reviewer can start this application locally with any valid configuration in the .env file and this application should works as described in the task 9.

How to test Task 9.1.

Clone repo & install dependencies with following commands:

git clone https://github.com/maksumov/rss-shop-be.git
cd rss-shop-be
git fetch origin pull/14/head:task-9
git checkout task-9
cd src/bff-service
npm install

After installing dependencies you should create .env file in the root folder of bff-service (see .env.sample for example of configuration or just rename this file to .env file).

And finally you need to compile TypeScript files by running tsc and then you can run service by npm run start:dev.

This PR closes #12

Task 9.2

• [x] The bff-service should be deployed with Elastic Beanstalk.
• [x] The bff-service call should be redirected to the appropriate service : product-service or CART.
• [x] The response from the bff-service should be the same as if product-service or CART services were called directly.

This PR closes #13

Additional Tasks

Add Cache

• [x] Add a cache at the bff-service level for a request to the getProductsList function of the product-service.
• [x] The cache should expire in 2 minutes.

How to test caching

• Get products list from BFF link
• Create new product (see example below):

  curl --header "Content-Type: application/json" --request POST --data '{"count":20,"price":100,"description":"Это описание нового продукта","title":"Новый продукт"}' https://12yhrnlj11.execute-api.eu-west-1.amazonaws.com/dev/products

• Get products list (again from BFF Link) - result shouldn’t have new product
• Wait more than 2 minutes
• Get products list from BFF Link - result should have new product

How to test caching (alternative method)

• Start this application locally (like testing Task 9.1)
• Get products list from local url (like http://localhost:7000/products) a few times in a row
• Look in the console to find messages how each request was processed: from the cache or using the request (Request ${url} is handled from cache... or Request ${url} is handled from service request...)
• Wait more than 2 minutes from the first request and make another request for the product list
• Look in the console to find how the request was processed: from the cache or using the request

This PR closes #15

NestJS implementation

• [ ] Use NestJS to create bff-service instead of express

Working on closing the task #16

Self-check

Main tasks score: 5/5 Additional tasks score: 1/2 Total expected score: 6/7

Data for Task Evaluation

URLs

• FE App:
  • Store URL
• Product Service:
  • Direct link
  • BFF Link
• Cart Service:
  • Direct Link to Beanstalk URL
  • Api Gateway Link to Beanstalk
  • BFF Link

[aleksei-bulgak-study]

For case when url contains only service name and query params application responds with

[maksumov]

For case when url contains only service name and query params application responds with

This is because the BFF app can't find a service matching the name products?test=test. The name of the service to be proxied is defined by the application via a split by a character /. You might as well expect to get a result by making a request to http://maksumov-bff-api-dev.eu-west-1.elasticbeanstalk.com/products-test=test endpoint

[aleksei-bulgak-study]

For case when url contains only service name and query params application responds with

This is because the BFF app can't find a service matching the name products?test=test. The name of the service to be proxied is defined by the application via a split by a character /. You might as well expect to get a result by making a request to http://maksumov-bff-api-dev.eu-west-1.elasticbeanstalk.com/products-test=test endpoint

but url is valid. In my opinion result url sould be smth like https://productUrl?test=test

[maksumov]

but url is valid. In my opinion result url sould be smth like https://productUrl?test=test

Url is not valid for BFF. If you want to call products service - you should send request to http://maksumov-bff-api-dev.eu-west-1.elasticbeanstalk.com/products/?test=test endpoint

[aleksei-bulgak-study]

Here is example from task description {bff-service-url}/{recipient-service-name}?var1=someValue and it also has query parameter without any tailing slashes after service name

[maksumov]

I changed the app and deployed a new version