Environment (.env) ​

When it comes to creating a production-grade application, using the environment variable in the application is de facto.

Base on spf13/viper: Go configuration with fangs (github.com)

Why should we use the environment variable? ​

Suppose you have an application with many features and each feature needs to access the Database. You configured all the DB information like DBURL, DBNAME, USERNAME and PASSWORD in each feature.

There are a few major disadvantages to this approach, but there can be many.

Security Issue: ​

• You're entering all the information in the code. Now, all unauthorized person also has access to the DB.
• If you're using a code versioning tool git then the details of your DB will go public once you push the code.

Code Management: ​

• If you are changing a single variable then you have to change all the features. There is a high possibility that you'll miss one or two. 😌 been there
• You can categorize the environment variables like PROD, DEV, or TEST. Just prefix the variable with the environment.

At the start, it might look like some extra work, but this will reward you a lot in your project.

It is time for some action.

Interface ​

type IENV interface {
	Config() *ENVConfig
	IsDev() bool
	IsTest() bool
	IsMock() bool
	IsProd() bool
	Bool(key string) bool
	Int(key string) int
	String(key string) string
	All() map[string]string
}

Usage ​

1. Use from default ENV ​

// SomeFunc is a method of the `someService` type.
// It prints the hostname of the database configured in the ENV.
func (s someService) SomeFunc() {
  // Retrieve the database hostname from the ENV configuration using the context
  dbHost := s.ctx.ENV().Config().DBHost
  // Print the database hostname
  fmt.Println("ENV Database hostname: ", dbHost)
}

2. Create new ENV ​

2.1 Update .env file ​

CUSTOM_SOMETHING=custom_env

2.2 Add env key to constant file (consts/env.const.go) ​

const (
  ENVCustomSomething = "CUSTOM_SOMETHING"
)

2.3 Use new ENV ​

// SomeFunc is a method of the `someService` type.
// It retrieves a custom environment variable called "ENVCustomSomething" and prints its value.
func (s someService) SomeFunc() {
  // Retrieve the value of the custom environment variable "ENVCustomSomething"
  somethingENV := s.ctx.ENV().String(consts.ENVCustomSomething)
  // Print the value of the custom environment variable
  fmt.Println("something value: ", somethingENV)
}

Default ENV Key ​

Application: ​

• HOST // Host for the application
• ENV // Environment (e.g., dev, prod, mock, test)
• SERVICE // Service name (e.g., api, seed, cronjob, migration)

Logging: ​

• LOG_LEVEL // Log level (e.g., debug, info, warn, error)
• LOG_HOST // Host for logging service (graylog)
• LOG_PORT // UDP Port for logging service (graylog)

Error Tracking: ​

• SENTRY_DSN // DSN for Sentry error tracking service

Database (Relational): ​

• DB_DRIVER // Database driver (e.g., mysql, postgres, mssql)
• DB_HOST // Database host
• DB_HOST // Database host
• DB_NAME // Database name
• DB_USER // Database username
• DB_PASSWORD // Database password
• DB_PORT // Database port

Database (MongoDB): ​

• DB_MONGO_HOST // MongoDB host
• DB_MONGO_NAME // MongoDB database name
• DB_MONGO_USERNAME // MongoDB username
• DB_MONGO_PASSWORD // MongoDB password
• DB_MONGO_PORT // MongoDB port

Message Queue: ​

• MQ_HOST // Message Queue host
• MQ_USER // Message Queue username
• MQ_PASSWORD // Message Queue password
• MQ_PORT // Message Queue port

Cache Service (Redis): ​

• CACHE_PORT // Cache service port
• CACHE_HOST // Cache service host

Amazon S3: ​

• S3_ENDPOINT // S3 endpoint
• S3_ACCESS_KEY // S3 access key
• S3_SECRET_KEY // S3 secret key
• S3_BUCKET // S3 bucket name
• S3_HTTPS // Use HTTPS for S3 (boolean value)
• S3_REGION // S3 region

Email SMTP Server: ​

• EMAIL_SERVER // Email server
• EMAIL_PORT // Email server port
• EMAIL_USERNAME // Email server username
• EMAIL_PASSWORD // Email server password
• EMAIL_SENDER // Email sender address

Windows Remote Management (WinRM): ​

• WINRM_HOST // Windows Remote Management (WinRM) host
• WINRM_USER // WinRM username
• WINRM_PASSWORD // WinRM password
• WINRM_PORT // WinRM port

ABCI: ​

• ABCI_ENDPOINT // ABCI endpoint

Decentralized Identifiers (DID): ​

• DID_METHOD_DEFAULT // Default DID method
• DID_KEY_TYPE_DEFAULT // Default DID key type