How to work with environment variables in golang using godotenv
Jul 13, 2025 am 02:04 AMThe steps to manage Go project environment variables using godotenv are as follows: 1. Install the package and import it, and call godotenv.Load() to load the .env file; 2. Create a .env file in the .key=value format in the project root directory for code to read through os.Getenv; 3. Support multi-environment configuration by specifying file names such as .env.development; 4. Be careful to avoid submitting .env to Git, support nested variable references and default value processing. In addition, it is recommended to directly inject system variables in the production environment.
Using .env
files to manage environment variables is a common requirement in Go projects, and godotenv
is a very popular library that allows you to read environment variables like production environments when developing locally. Below are some practical uses and precautions.

Install godotenv
To use godotenv
, you first need to install its Go package:

go get github.com/joho/godotenv/autoload
Or if you just want to load manually at initialization, you can just introduce:
go get github.com/joho/godotenv
Then import and call in the code:

import "github.com/joho/godotenv" err := godotenv.Load() if err != nil { // Handle errors, such as file does not exist, etc.}
How to create and use .env files
The .env
file is usually placed in the project root directory, and the content format is as follows:
DB_USER=myuser DB_PASSWORD=secret123 PORT=8080
These values can be obtained in the code by os.Getenv("DB_USER")
.
Note: If a variable is not defined in
.env
,os.Getenv
will return an empty string. Therefore, it is best to make a non-empty judgment before use.
Supports multiple environment configurations (such as .env.development and .env.production)
Sometimes you want to load different .env
files according to the current running environment. For example:
-
.env.development
-
.env.production
You can specify which file to load like this:
godotenv.Load(".env." os.Getenv("GO_ENV"))
If you do not set GO_ENV
, you can set it to development
by default:
env := os.Getenv("GO_ENV") if env == "" { env = "development" } godotenv.Load(".env." env)
This way, you can flexibly switch configurations in different environments.
Some easily overlooked but important details
Don't submit
.env
to Git
Remember to add.env
to.gitignore
to avoid leakage of sensitive information.Support nested variable references
For example, you can write it as:HOST=localhost URL=http://${HOST}:8080
In this way
os.Getenv("URL")
will behttp://localhost:8080
.Default value processing
If the variable may be missing, you can useos.Getenv
to add judgment, or useos.LookupEnv
to handle it more safely:port, exists := os.LookupEnv("PORT") if !exists { port = "8000" }
Basically that's it. Using
godotenv
well can make local development more convenient and configuration more unified. Remember not to abuse it. It is recommended to inject configuration directly through system environment variables in the production environment.The above is the detailed content of How to work with environment variables in golang using godotenv. For more information, please follow other related articles on the PHP Chinese website!

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