GO Transfer

GO Transfer is a simplified banking back-end API that create users account, authenticate the user and make transactions between accounts.

This API is meant only to be an ability assessment of my skills as a developer, it has no meaningful use or contribution.

Features

This API has three Endpoints as follow

• /accounts

  • Create user account
  • Return the list of all accounts in the database
  • Return the balance for a specific user

• /login

  • Authenticate the user and return a token
  • Support Json Web Tokens

• /transfer

  • Allows transactions between accounts (Requires authentication)
  • List all the transaction for a specific user (Requires authentication)

Requirements

github.com/go-playground/validator v9.31.0
github.com/golang-jwt/jwt v3.2.2
github.com/labstack/echo/v4 v4.9.0
github.com/mattn/go-sqlite3 v1.14.15
github.com/stretchr/testify v1.7.0

Quickstart

Docker

docker pull geronaso/go-transfer
docker build --tag geronaso/go-transfer . 
docker run -p 8080:8080 -it geronaso/go-transfer

Local

git clone https://github.com/Geronaso/Go-transfer.git
cd go-transfer
go mod init
go mod tidy
go run main.go

Google Cloud Provider

https://go-transfer-geronaso-bcaeeczeha-uc.a.run.app

I made a CI/CD pipeline that runs written tests and deploys at production, it is further explained at Pipeline

I also recommend testing it with Postman

Database

The database.db file is pre loaded with two tables, account and transfers. These tables are also pre loaded with some values for easy testing:

id	user	cpf	balance	date_joined	password
1	Paulo	12345678905	1200	2022-10-06T01:06:53-03:00	hash(123456)
2	Carina	12345678903	1300	2022-10-06T01:06:55-03:00	hash(123456)
3	Juliana	12345678904	500	2022-10-06T01:07:29-03:00	hash(123456)

id	account_origin_id	account_destination_id	amount	created_at
1	3	2	300.0	2022-10-06T01:08:23-03:00
2	3	2	200.0	2022-10-06T01:08:35-03:00

• This might not reflect the database at GCP.

Endpoints

/accounts

• Request (application/json)

• Method [POST]

  • Body

        {
            "name": "Carina",
            "cpf": "12345678903",
            "secret": "123456"
        }

• Response 200 (application/json)
  • Body

        {
            "Account Created"
        }

/accounts

• Request (application/json)

• Method [GET]

• Response 200 (application/json)

  • Body

        [
            {
                "Name": "Paulo",
                "Cpf": "12345678905",
                "Balance": 1200,
                "Date_Joined": "2022-10-06T01:06:53-03:00"
            },
            {
                "Name": "Carina",
                "Cpf": "12345678903",
                "Balance": 1300,
                "Date_Joined": "2022-10-06T01:06:55-03:00"
            },
            {
                "Name": "Juliana",
                "Cpf": "12345678904",
                "Balance": 500,
                "Date_Joined": "2022-10-06T01:07:29-03:00"
            }
        ]

/accounts/:id/balance

• Request (application/json)

• Method [GET]

• Response 200 (application/json)

  • Body

        {
            "1200"
        }

/login

• Request (application/json)

  • Method [POST]

  • Body

        {
            "cpf": "12345678903",
            "secret": "123456"
        }

• Response 200 (application/json)
  • Body

        {
        "Token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJjcGYiOiIxMjM0NTY3ODkwNCIsImV4cCI6MTY2NTExNjU3Nn0.nyHJ-sOm8vk3fusByDgw1opeMlu2zA8NXFdbvbbDe0Y"
        }

JWT

The token provided by the API expires after 24 hours.

/transfer

• Request (application/json)

  • Method [GET]

  • Headers

            Authorization: Bearer [access_token]

• Response 200 (application/json)
  • Body

        [
            {
                "Id": 1,
                "Account_origin_id": 3,
                "Account_destination_id": 2,
                "Amount": 300,
                "Created_at": "2022-10-06T01:08:23-03:00"
            },
            {
                "Id": 2,
                "Account_origin_id": 3,
                "Account_destination_id": 1,
                "Amount": 200,
                "Created_at": "2022-10-06T01:08:35-03:00"
            }
        ]

/transfer

• Request (application/json)

  • Method [POST]

  • Headers

            Authorization: Bearer [access_token]

• Body

        {
            "destination_cpf": "12345678902",
            "amount": 700
        }

• Response 200 (application/json)
  • Body

        {
            "Transfer Completed"
        }

Testing Endpoints

POSTMAN

I have made a workspace at postman for easy testing.

The req folder also has some http templates to do some easy testing, but you can also use your preferred tool to test the endpoints!

Tests

The folder tests has some written tests for the endpoint /accounts. The database.db localized in the tests folder is initialized with empty tables for testings, after running the tests it is necessary to re-initialize the table with the init.sql script. So if you want to run the tests again, please run the script before testing.

go test .\tests\

Pipeline

The pipeline is ilustrated in the GCP-Deploy.yml file at .github/workflows

It runs the following steps on push.

graph TD;
    Authenticate_GCP-->Docker_Build;
    Docker_Build-->Go_test;
    Go_test-->GCP_Deploy;

Loading

Authenticate GCP authenticates at my account at GCP.

Docker Build makes the docker file for deployment.

Go test tests the docker image with written tests.

GCP Deploy finally deploy the application to production at GCP.

TO-DO

• Write better error messages.

  • It is necessary to write better error messages specially for database related errors, so it becomes easier to debug and also to be more of a RESTful API.

• Write more tests

  • Currently only the endpoint /accounts has written tests, it is necessary to write tests for the others endpoints as well.

Author

Cézar Murilo ([email protected])

License

GNU General Public License v3.0 or later.

See LICENSE for the full text.