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 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