environment configuration (#15)

* environment configuration

* simplify

* fix test

* small fix

helium.go

@@ -6,6 +6,7 @@ import (
 	stdlog "log"
 	"os"
 	"reflect"
+	"strings"
 
 	"github.com/im-kulikov/helium/logger"
 	"github.com/im-kulikov/helium/module"
@@ -47,12 +48,13 @@ func New(cfg *Settings, mod module.Module) (*Helium, error) {
 		if cfg.Prefix == "" {
 			cfg.Prefix = cfg.Name
 		}
+		cfg.Prefix = strings.ToUpper(cfg.Prefix)
 
-		if tmp := os.Getenv("HELIUM_CONFIG"); tmp != "" {
+		if tmp := os.Getenv(cfg.Prefix + "_CONFIG"); tmp != "" {
 			cfg.File = tmp
 		}
 
-		if tmp := os.Getenv("HELIUM_CONFIG_TYPE"); tmp != "" {
+		if tmp := os.Getenv(cfg.Prefix + "_CONFIG_TYPE"); tmp != "" {
 			cfg.Type = tmp
 		}
 

helium_test.go

@@ -49,10 +49,12 @@ func TestHelium(t *testing.T) {
 
 			defer os.Remove(tmpFile.Name()) // clean up
 
-			os.Setenv("HELIUM_CONFIG", tmpFile.Name())
-			os.Setenv("HELIUM_CONFIG_TYPE", "toml")
+			os.Setenv("ABC_CONFIG", tmpFile.Name())
+			os.Setenv("ABC_CONFIG_TYPE", "toml")
 
-			h, err := New(&Settings{}, module.Module{
+			h, err := New(&Settings{
+				Name: "Abc",
+			}, module.Module{
 				{Constructor: func(cfg *settings.Core) App {
 					c.So(cfg.File, ShouldEqual, tmpFile.Name())
 					c.So(cfg.Type, ShouldEqual, "toml")