Can Viper read env file naming like .env.[mode](e.g. .env.local, .env.production, etc.)?

[100gle]

It seems that Viper currently only supports reading key-value content from .env configuration file:

package main

import "github.com/spf13/viper"

func main() {
	viper.AddConfigPath(".")
	viper.SetConfigFile(".env")
	if err := viper.ReadInConfig(); err != nil {
		panic("can't read config")
	}

	// handle key value
	// ...
}

However, when I try to read the .env.local or .env.production (they are same as .env, but usually for front-end developers and front-end frameworks), Viper will be treat .local or .production as file type and then raise error message like error="Unsupported Config Type \".local\"":

package main

import "github.com/spf13/viper"

func main() {
	viper.AddConfigPath(".")

        // change here
	viper.SetConfigType(".local")
	viper.SetConfigName(".env")
        // end

	if err := viper.ReadInConfig(); err != nil {
		panic("can't read config")
	}

	// handle key value
	// ...
}

So there is any way to let Viper read those files?

[keelus]

It supports it. You have to specify the type first, and then the file name:

func main() {
	viper.SetConfigType("env")
	viper.SetConfigFile(".env.local")

	if err := viper.ReadInConfig(); err != nil {
		fmt.Println(".env.local not found. Trying with .env ...")

		viper.SetConfigFile(".env")
		if err2 := viper.ReadInConfig(); err2 != nil {
			panic("Error reading the .env file")
		} else {
			fmt.Println(".env loaded")
		}
	} else {
		fmt.Println(".env.local loaded")
	}

	// Handle keys
}

[100gle]

It works! Thank you keelus!