Task 4 - integration with NoSQL

[bwire]

Task 4.1.

• Two tables created in AWS DynamoDB (products, stocks) and filled with test data;
• A sh-script provided to fill up tables: ./scripts/dynamo/fill-tables.sh;

Task 4.2

• New environment variables from table names created and all lambdas configured to use them;
• lambdas get data form the database. Product-service API link: Product-service API

Task 4.3

• The new endpoint and lambda function for creating a new product added. Can be checked via Postman or VS Code Thunder client: POST: (https://1lwpgiz791.execute-api.eu-west-1.amazonaws.com/products. Payload example:

{ "id": "6ec0bd7f-11c0-43da-975e-2a8ad9ebae0b", "title": "Just test", "description": "Improving the Design of Existing Code shed light on the refactoring process, describing the principles and best practices for its implementation.", "price": 25, "count": 8 }

Additional tasks:

• POST /products lambda functions returns error 400 status code if product data is invalid - done. For the sake of simplicity - all fields in the payload are checked including the id - which is expected from the client-side! Example error (https://1lwpgiz791.execute-api.eu-west-1.amazonaws.com/products/23):
  { "message": "Product with id 23 not found" };
• All lambdas return error 500 status code on any error (DB connection, any unhandled error in code) - done. One can observe it in the code of every lambda handler - their code are wrapped in try/catch blocks and every catch process different unexpected errors (return errorResponse(err);). errorRespose uses status code 500 by default;
• All lambdas do console.log for each incoming requests and their arguments - done. Can be observed in every lambda handler (./src/handlers): console.log('Incoming request', event);
• Use RDS instance instead of DynamoDB tables. Do not commit your environment variables to github! - done. RDS instance for Postgres configured. Scripts for creating tables and adding data can be found here: ./scripts/postgres. To switch between DynamoDB and Postgres it is enough to flip USE_NOSQL_DB environment variable in every lambda or just redeploy the stack with the new value, for example USE_NOSQL_DB=false- in this case the Postgres-specific implementation will be used.
• Transaction based creation of product - done for both DynamoDB and Postgres implementations (createProduct only - no transactional read).

Swagger documentation updated and can be found here:
./product-api.json
Front-end (uses the last backend code and data): https://d1eot7ucp9tkae.cloudfront.net
Front-end PR (just in case): bwire/nodejs-aws-shop-react#2