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/*
Package env handles environment variables in a structured manner.
See the README at https://github.com/peter-edge/env-go/blob/master/README.md for more details.
*/
package env // import "go.pedge.io/env"
import (
"fmt"
"io"
"os"
"strings"
)
// Decoder decodes an env file.
type Decoder interface {
Decode() (map[string]string, error)
}
// NewEnvFileDecoder returns a new Decoder that decodes an env file
// of the form key=value.
func NewEnvFileDecoder(reader io.Reader) Decoder {
return newEnvFileDecoder(reader)
}
// NewJSONDecoder returns a new Decoder that decodes a JSON object.
func NewJSONDecoder(reader io.Reader) Decoder {
return newJSONDecoder(reader)
}
// Populate populates an object with environment variables.
//
// The environment has precedence over the decoders, earlier
// decoders have precedence over later decoders.
func Populate(object interface{}, decoders ...Decoder) error {
return populate(object, decoders)
}
// Main runs the common functionality needed in a go main function.
// appEnv will be populated and passed to do, defaultEnv can be nil
// if there is an error, os.Exit(1) will be called.
func Main(do func(interface{}) error, appEnv interface{}, decoders ...Decoder) {
if err := Populate(appEnv, decoders...); err != nil {
mainError(err)
}
if err := do(appEnv); err != nil {
mainError(err)
}
os.Exit(0)
}
func mainError(err error) {
if errString := strings.TrimSpace(err.Error()); errString != "" {
fmt.Fprintf(os.Stderr, "%s\n", errString)
}
os.Exit(1)
}
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