library-microservices

Library Microservices

Microservices

1. Books service
2. Customers service
3. Borrowing service

Dataset

https://www.kaggle.com/jealousleopard/goodreadsbooks

Tech Stack

• Go
  • go-kit for the microservices architecture
  • gorm to interact with the db
• PostgreSQL
• Docker

Test

Create DB

Create a PostgreSQL server with Docker:

sudo docker run --rm --name library_db -e POSTGRES_PASSWORD=password -p 5432:5432 -d postgres
sudo docker exec -it library_db sh

Inside PostgreSQL container:

su postgres
psql
create database library_db;
\c library_db

Run microservices

go run main.go

Make same requests:

POST

curl -XPOST localhost:8080/book \
    -d '{
            "book":{
                "title":"Atomic Habits",
                "author":"Geronimo Stilton",
                "average_rating":4.5
            }
    }'

{"id":1,"error":null}

GET

curl -XGET localhost:8080/book/1

{"book":{"id":1,"title":"Atomic Habits","author":"Geronimo Stilton","average_rating":4.5,"isbn":"","isbn13":"","language_code":"","num_pages":0,"ratings_count":0,"text_reviews_count":0,"publication_date":"0001-01-01T00:49:56+00:49","publisher":""},"error":null}

PUT

curl -XPUT localhost:8080/book/1 \
    -d '{
            "book":{
                "title":"Formaggio",
                "author":"Geronimo Stilton",
                "average_rating":4.5
            }
    }'

DELETE

curl -XDELETE localhost:8080/book/1

Docker

docker build --tag library-app .
docker run --rm -it -p 8080:8080 --name my-library-app library-app

docker-compose

docker-compose -f docker-compose.test.yml build
docker-compose -f docker-compose.test.yml up
docker-compose -f docker-compose.test.yml down

For testing:

sudo docker-compose -f docker-compose.test.yml up --build --abort-on-container-exit
sudo docker-compose -f docker-compose.test.yml down

or:

sudo make test 

To Do

• Fix http mux in main.go
• Response must contain a field "success"
• Add logging middleware
• Add tests for book service
• Move all to containers
• Add make command to deploy a local postgres for debugging

What I learned

go-kit

• if I return an error different from nil in functions like Make...Endpoint(), then the DecodeResponse function is not called. Thus, I return a nil error and the response struct is filled with the error string.

• multistage builds in Docker to reduce the number of identical layers. Using interediate target layers.

• testting.M in Go is used to wrap tests. It can be used to create resources before running the tests, close the resources after them.

• makefile to better organize commands.

• use pointer struct methods when you want to modify struct members