How to Assign Default Values to Empty Environment Variables in Go?

Assigning Default Values for Empty Environment Variables in Go

In Python, assigning a default value when an environment variable is not set is straightforward using os.getenv('MONGO_PASS', 'pass'). However, in Go, there is no built-in method to achieve this.

Using Conditional Statements

One approach is to use an if statement:

if os.Getenv("MONGO_PASS") == "" {
    mongoPassword = "pass"
}

However, this may not work as intended if you need to check multiple environment variables and act on the results within the if block.

Creating a Helper Function

To simplify the logic, you can create a helper function:

func getEnv(key, fallback string) string {
    value := os.Getenv(key)
    if len(value) == 0 {
        return fallback
    }
    return value
}

This function checks if the environment variable is empty and returns the fallback value if necessary.

Using os.LookupEnv (Optimized)

Another approach is to use os.LookupEnv:

func getEnv(key, fallback string) string {
    if value, ok := os.LookupEnv(key); ok {
        return value
    }
    return fallback
}

os.LookupEnv returns a boolean indicating whether the environment variable exists, allowing for a more efficient check.

Additional Considerations

Note that if the environment variable is empty (an empty string), the fallback value will be returned. If you need to differentiate between an unset environment variable and an empty string, use the optimized version using os.LookupEnv.

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