1. Hexagonal Architecture.
2. REST Api.
3. Dependency Injection.
4. Database Transactions.
5. Structured Error Library.
6. Concurrent Server with Graceful Shutdown.
7. Distributed Logging.

1. Go
2. Postgres
3. Docker

1. Pgx (Postgres Driver)
2. Gorilla/Mux (Routing)
3. Validator (JSON Validatin Middleware)

1. GetAllCustomers:     GET     /customers?status=
2. GetCustomer:         GET     /customers/:id
3  NewAccount:          POST    /customers/:id/accounts
4. NewTransaction:      POST    /customers/:id/account/:account_id

1. JSON (REST)
2. CSV (Database bulk insert)

1. Customer:
    - id: bigserial
    - name: string
    - date_of_birth: date
    - city: string
    - zipcode: string
    - status: small int

2. Accounts:
    - id: int
    - customer_id: int
    - opening_date: timestamp
    - amount: decimal
    - account_type: string

4. Users:
    - id: bigserial
    - username: string
    - password: string
    - role: string

3. Transactions:
    - id: bigserial
    - account_id: int
    - type: string
    - amount: decimal
    - transacation_date: timestamp

1. Customer:
    - Get All Customers By Status
    - Get Customer By Id

2. Account:
    - New Account
    - Get Account By account_id
    - Get all accounts by account_id and customer_id

3. Transaction:
    - New Transaction

1. Role based access control.
2. JWT based authentication.
3. JWT based authorization.
4. JWT based token verification.
5. JWT based token refresh(TODO).

1. (user -> auth-server) login request.
2. (auth-server -> user) token in response.
3. (user -> banking-server) request resource with token.
4. (banking server -> auth server) verify the token.
5. (auth-server -> banking-server) token verification response.
6. (bankng-server -> user) resource response.

1. GetAllCustomers:     GET     /customers
2. GetCustomer:         GET     /customers/:id
3  NewAccount:          POST    /customers/:id/accounts
4. NewTransaction:      POST    /customers/:id/account/:account_id

1. Role: admin  -> All.
2. Role: user   -> GetCustomer & NewTransaction.

1. Validity of the token(include expiry time and signature).
2. Verify if the role has access to the resource.
3. vefify if the resource being accessd by same user.