[FAB-3558] Allow specific env variable prefix for SDK

Change-Id: I2c7c76233c2069ce1d40772968b613bfd76b9cb0
Signed-off-by: Emir Heidinger <emir.heidinger@securekey.com>

Author: emirsh

config/config.go

@@ -57,8 +57,13 @@ const cmdRoot = "fabric_sdk"
 // InitConfig ...
 // initConfig reads in config file
 func InitConfig(configFile string) error {
+	return InitConfigWithCmdRoot(configFile, cmdRoot)
+}
 
-	myViper.SetEnvPrefix(cmdRoot)
+// InitConfigWithCmdRoot reads in a config file and allows the
+// environment variable prefixed to be specified
+func InitConfigWithCmdRoot(configFile string, cmdRootPrefix string) error {
+	myViper.SetEnvPrefix(cmdRootPrefix)
 	myViper.AutomaticEnv()
 	replacer := strings.NewReplacer(".", "_")
 	myViper.SetEnvKeyReplacer(replacer)

config/config_test.go

@@ -81,7 +81,7 @@ func TestMultipleVipers(t *testing.T) {
 	}
 }
 
-func TestEnvironmentVariables(t *testing.T) {
+func TestEnvironmentVariablesDefaultCmdRoot(t *testing.T) {
 	testValue := myViper.GetString("env.test")
 	if testValue != "" {
 		t.Fatalf("Expected environment variable value to be empty but got: %s", testValue)
@@ -105,6 +105,30 @@ func TestEnvironmentVariables(t *testing.T) {
 	}
 }
 
+func TestEnvironmentVariablesSpecificCmdRoot(t *testing.T) {
+	testValue := myViper.GetString("env.test")
+	if testValue != "" {
+		t.Fatalf("Expected environment variable value to be empty but got: %s", testValue)
+	}
+
+	err := os.Setenv("TEST_ROOT_ENV_TEST", "456")
+	defer os.Unsetenv("TEST_ROOT_ENV_TEST")
+
+	if err != nil {
+		fmt.Println(err.Error())
+	}
+
+	err = InitConfigWithCmdRoot("../test/fixtures/config/config_test.yaml", "test_root")
+	if err != nil {
+		fmt.Println(err.Error())
+	}
+
+	testValue = myViper.GetString("env.test")
+	if testValue != "456" {
+		t.Fatalf("Expected environment variable value but got: %s", testValue)
+	}
+}
+
 func TestMain(m *testing.M) {
 	err := InitConfig("../test/fixtures/config/config_test.yaml")
 	if err != nil {