I am trying to make Viper read my environment variables, but its not working. Here is my configuration:
# app.yaml
dsn: RESTFUL_APP_DSN
jwt_verification_key: RESTFUL_APP_JWT_VERIFICATION_KEY
jwt_signing_key: RESTFUL_APP_JWT_SIGNING_KEY
jwt_signing_method: "HS256"
And my config.go
file:
package config
import (
"fmt"
"strings"
"github.com/go-ozzo/ozzo-validation"
"github.com/spf13/viper"
)
// Config stores the application-wide configurations
var Config appConfig
type appConfig struct {
// the path to the error message file. Defaults to "config/errors.yaml"
ErrorFile string `mapstructure:"error_file"`
// the server port. Defaults to 8080
ServerPort int `mapstructure:"server_port"`
// the data source name (DSN) for connecting to the database. required.
DSN string `mapstructure:"dsn"`
// the signing method for JWT. Defaults to "HS256"
JWTSigningMethod string `mapstructure:"jwt_signing_method"`
// JWT signing key. required.
JWTSigningKey string `mapstructure:"jwt_signing_key"`
// JWT verification key. required.
JWTVerificationKey string `mapstructure:"jwt_verification_key"`
}
func (config appConfig) Validate() error {
return validation.ValidateStruct(&config,
validation.Field(&config.DSN, validation.Required),
validation.Field(&config.JWTSigningKey, validation.Required),
validation.Field(&config.JWTVerificationKey, validation.Required),
)
}
func LoadConfig(configpaths ...string) error {
v := viper.New()
v.SetConfigName("app")
v.SetConfigType("yaml")
v.SetEnvPrefix("restful")
v.AutomaticEnv()
v.SetDefault("error_file", "config/errors.yaml")
v.SetDefault("server_port", 1530)
v.SetDefault("jwt_signing_method", "HS256")
v.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
for _, path := range configpaths {
v.AddConfigPath(path)
}
if err := v.ReadInConfig(); err != nil {
return fmt.Errorf("Failed to read the configuration file: %s", err)
}
if err := v.Unmarshal(&Config); err != nil {
return err
}
// Checking with this line. This is what I get:
// RESTFUL_JWT_SIGNING_KEY
fmt.Println("Sign Key: ", v.GetString("jwt_signing_key"))
return Config.Validate()
}
This line fmt.Println("Sign Key: ", v.GetString("jwt_signing_key"))
gives me just the key passed in the yaml file RESTFUL_JWT_SIGNING_KEY
. I don't know what I'm doing wrong.
According to doc:
AutomaticEnv is a powerful helper especially when combined with SetEnvPrefix. When called, Viper will check for an environment variable any time a viper.Get request is made. It will apply the following rules. It will check for a environment variable with a name matching the key uppercased and prefixed with the EnvPrefix if set.
So, why isn't it reading the environment variables?
Using JSON
{
"dsn": "RESTFUL_APP_DSN",
"jwt_verification_key": "RESTFUL_APP_JWT_VERIFICATION_KEY",
"jwt_signing_key": "RESTFUL_APP_JWT_SIGNING_KEY",
"jwt_signing_method": "HS256"
}
And my parser looks like thus:
// LoadConfigEnv loads configuration from the given list of paths and populates it into the Config variable.
// Environment variables with the prefix "RESTFUL_" in their names are also read automatically.
func LoadConfigEnv(environment string, configpaths ...string) error {
v := viper.New()
v.SetConfigName(environment)
v.SetConfigType("json")
v.SetEnvPrefix("restful")
v.AutomaticEnv()
v.SetDefault("jwt_signing_method", "HS256")
v.SetDefault("error_file", "config/errors.yaml")
v.SetDefault("server_port", 1530)
v.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
for _, path := range configpaths {
v.AddConfigPath(path)
}
if err := v.ReadInConfig(); err != nil {
return fmt.Errorf("Failed to read the configuration file: %s", err)
}
if err := v.Unmarshal(&Config); err != nil {
return err
}
return Config.Validate()
}
In the Validate
function, I decided to check the Config
struct, and this is what I got:
Config: {config/errors.yaml 1530 RESTFUL_APP_DSN HS256 RESTFUL_APP_JWT_SIGNING_KEY RESTFUL_APP_JWT_VERIFICATION_KEY}
The command env displays all environment variables and their values.
Installing Viper is similar to installing any package in Go. The first step is to initialize the Go mod file. The best way to do this is to initialize the folder with git init . Next, set up the git origin using git remote add origin ORIGIN_URL , then initialize the project with go mod init .
The code in my question didn't actually show what I was trying to solve. After understanding what was wrong, I believe, the code here would have ran locally in my Development Environment.
According to Viper documentation:
AutomaticEnv is a powerful helper especially when combined with SetEnvPrefix. When called, Viper will check for an environment variable any time a viper.Get request is made. It will apply the following rules. It will check for an environment variable with a name matching the key uppercased and prefixed with the EnvPrefix if set.
This line here says it all:
It will check for a environment variable with a name matching the key uppercased and prefixed with the EnvPrefix if set
The prefix set with v.SetEnvPrefix("restful")
would be expecting a .yaml
with key value of:
Example app.yaml:
dsn: RESTFUL_DSN
Notice the DSN being the Lowercased Key and it being used as a Suffix
of RESTFUL_DSN
In my situation, I was doing this instead:
Example app.yaml:
dsn: RESTFUL_APP_DSN
So, it was checking for RESTFUL_DSN
in my environment instead of RESTFUL_APP_DSN
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