Setup database

[gutakk]

What happened 👀

Resolve #4

• Add database docker container for development and test environments.
• Add env-setup and env-teardown make command to run and stop database container.
• Add Viper as config management tools.
• Add toml config file with dev and test database url.
• Load config to get the database url vary by gin mode.
• Add gorm as an ORM.
• Application and test are connect to database.
• Add common get config by type functions (bool, float, int and string) as a helper.
• Add get database connection function as a helper.

Insight 📝

I choose Viper because Viper is one of the most popular config management tools that support TOML format as TOML widely use for config type in Go.

You can get value from toml config file using viper as following.

# toml config file

[debug]
database_url = "db"

[test]
database_url = "test db"

You can get value using viper like this

// debug env
viper.GetString("debug.database_url")

// test env
viper.GetString("test.database_url")

How about release environment?
Since this release is focusing only Heroku, all env on Heroku doesn't contain prefix and TOML file doesn't support environment injection so I need to create function GetConfigPrefix vary by gin.Mode.

You can get the config value using helpers function for configs that depend on gin.Mode() and can use viper directly for config that not depend on gin.Mode().

Proof Of Work 📹

• Run development server (This will read database url from debug.database_url in config/app.toml)
  

• Run test (This will read database url from test.database_url in config/app.toml)
  

• Run application with release environment without provide DATABASE_URL
  

• Run application with release environment with DATABASE_URL
  

[olivierobert]

Since this method is only used internally, how about not exporting it?

[gutakk]

I export this function because I want to write unit test. config_test's package is helpers_test.

[olivierobert]

I saw that but I am not sure of the value-added to have such test as it will be implicitly tested in the other public methods.

[olivierobert]

Why separating this from bootstrap/database.go? Couldn't this be together? I don't see the point of having a helper for that 🤔 Also note that I did not see where GetDBConnection is actually used. I would assume that InitDatabase would use it but it's not. So for now, it seems like an unused method.

[gutakk]

Gorm does not have any function to get database connection after initialize so I need to create a function to get database connection from viper config. I think bootstrap should contains only initializer stuffs. That's why I decide to put GetDBConnection function at helpers. But yes this function is unused for now, I will remove this in this PR and will put it again in the PR that need to use database connection.

Removed in 28bb423

[olivierobert]

Helpers use should be minimized. It should not be your go-to place for code 🙈 bootstrap should indeed contain all initialization code but that also include any secondary methods like such helpers too. Keeping the implementation code close to where the methods are declared is a best practice. Especially, in this case, the "helper" method does not need to be shared as it will be used only in bootstrap and nowhere else.