goenv

goenv is a lightweight and dependency-free Go package for loading environment variables from .env files. It provides a simple and efficient alternative to other .env loading libraries, focusing on core functionality and ease of use.

 

Installation

go get https://github.com/cloudresty/goenv

 

Usage

 

Create a .env file:

In the root directory of your project, create a file named .env and add your environment variables in the format KEY=VALUE, one per line.

 

Example:

DB_HOST=localhost
DB_PORT=3000
DB_USER=myuser
DB_PASS=mypassword
API_KEY=your_secret_api_key
# MY_DISABLED_VAR=value_will_be_ignored

Note: Lines starting with # are treated as comments and ignored.

 

Import and use the goenv package:

package main

import (
    "fmt"
    "https://github.com/cloudresty/goenv"
)

// Global variables
var (
    dbHost = goenv.Get("DB_HOST")
    dbPort = goenv.Get("DB_PORT")
)

func main() {

    // Load environment variables from .env (automatically)
    goenv.Load()

    fmt.Println("DB_HOST:", dbHost)
    fmt.Println("DB_PORT:", dbPort)

    // Local variables with default values (if not set)
    // WARNING: Use the below method ONLY for development purposes!
    dbUser := goenv.Get("DB_USER", "root")
    dbPass := goenv.Get("DB_PASS", "password")

    // Example using Lookup
    apiKeyVal, exists := goenv.Lookup("API_KEY")
    if exists {
        fmt.Println("API_KEY (Lookup):", apiKeyVal)
    }

    // Example loading a custom file
    err := goenv.Load(".env.development")
    if err != nil {
        fmt.Println("Error loading .env.development:", err)
    }

    // Example using MustLoad (panics on error)
    // goenv.MustLoad(".env")
}

 

Functions

 

Load(filename ...string) error

Loads environment variables from the specified .env like .env.development or the default .env file if no filename is provided.

• filename ...string: Optional path to the custom .env file. If no filename is provided, it loads from the default .env file. If the default .env file does not exist, no error is returned.
• Returns an error if a specified custom file cannot be opened or read.
• Ignores empty lines and lines starting with # (comments).
• Only sets environment variables that are not already set in the current environment.

 

Lookup(key string) (string, bool)

Retrieves the value of an environment variable.

• key: The name of the environment variable.
• Returns the value of the variable and a boolean indicating whether the variable exists.

 

Get(key string, defaultValue ...string) string

Retrieves the value of an environment variable, optionally providing a default value if the variable is not found.

• key: The name of the environment variable.
• defaultValue ...string: Optional value to return if the variable does not exist. If no default is provided, it returns an empty string.
• Returns the value of the variable or the default value (or an empty string).

 

MustLoad(filename ...string)

Loads environment variables from the specified .env file or the default .env file and panics if an error occurs.

• filename ...string: Optional path to the .env.development file. If no filename is provided, it loads from the default .env file.
• Panics if the file cannot be opened or read.

 

Features

• Simple and lightweight: No external dependencies.
• Comment support: Ignores lines starting with #.
• Empty line handling: Ignores empty lines.
• Existing environment variable preservation: Only sets variables that are not already set.
• Convenient functions: Lookup and Get for easy access to environment variables.
• Error handling: Provides error return values for robust applications.
• Automatic .env loading: Loads .env by default without needing to specify a filename.
• Global variable initialization: Easily initialize global variables with environment values.
• MustLoad function: for cases where the env file is critical to application functionality.

 

Contributing

Contributions are welcome! Please feel free to submit issues or pull requests.

 

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Made with ❤️ by Cloudresty