Go Assessment Project

1.1 Description

A Go project with some API which retrieves/modifies some files containing the balance of accounts. The project should include a config file, which stores the directory of these files.

2.1 Requirements

• An API to create a number of accounts (balance files) in the directory
  • The balance of each account should be generated randomly, ranging from 1,000 to 100,000
  • These files (accounts' balances) could be created only once
• An API to get the balance of one/all account(s)
• An API to add number x to the balance of one/all account(s)
• Specify the pieces of code which have applied SOLID principle

3.1 Guide

• Comment
  • Search for #SOLID to see the examples of applied SOLID principles
  • Search for #TODO to see the possible improvements which I could not implement in the specified time period
  • Search for #Desc to see my reasons for making some specific decisions

3.2 Project structure

from the highest level to lowest:

1. API layer (./api)
2. The business layer (./account)
3. The internal layer (./internal)

4.1 How to use

4.2 Sample API call

• Create accounts URL: localhost:8080/accounts?number=1000 Verb: POST
• Get a balance URL: localhost:8080/accounts?id=12 Verb: GET
• Get sum of all balances URL: localhost:8080/accounts?result=aggregate Verb: GET
• increase a balance URL: localhost:8080/accounts?id=12&increase=1000 Verb: PUT
• increase all balances URL: localhost:8080/accounts?increase=1000 Verb: PUT

4.3 Config

• accountsDir: string, the directory which keeps the accounts files
• logsFile: string, the file path to store logs
• isConcurrent: boolean, to check if the service should behave concurrently
• isProduction: boolean, production vs debug (excluded from config_test)
• restPort: number, rest api port
• defaultAccountNumbers: number, the default number of accounts to created
• randomBalanceMinRange: number, the min range of random balance generation
• randomBalanceMaxRange: number, the max range of random balance generation
• maxConcurrentGoroutines: number, the max number of concurrent go routines
• accountFileExtension: text, the file extension of accounts including a dot (.txt)

5.1 TODO

• Add more tests
• Implement delete API
• Define more explicit error types
  • assert them in tests
  • use them to return more explicit HTTP error codes
• return error in get/update methods when there is no balance file
• Rollback changes when batch update is failed
• Wrap zap(logger) by an interface
• Put data validation on config (random balance generation range for instance)