Allow for setting of domain with enviroment variable

utils/config.go

@@ -217,6 +217,11 @@ func LoadConfig(fileName string) {
 		panic("Error decoding configuration " + err.Error())
 	}
 
+	// Grabs the domain from enviroment variable if not in configuration
+	if config.ServiceSettings.Domain == "" {
+		config.ServiceSettings.Domain = os.Getenv("MATTERMOST_DOMAIN")
+	}
+
 	configureLog(config.LogSettings)
 
 	Cfg = &config

utils/config_test.go

@@ -4,9 +4,24 @@
 package utils
 
 import (
+	"os"
 	"testing"
 )
 
 func TestConfig(t *testing.T) {
 	LoadConfig("config.json")
 }
+
+func TestEnvOverride(t *testing.T) {
+	os.Setenv("MATTERMOST_DOMAIN", "testdomain.com")
+
+	LoadConfig("config_docker.json")
+	if Cfg.ServiceSettings.Domain != "testdomain.com" {
+		t.Fail()
+	}
+
+	LoadConfig("config.json")
+	if Cfg.ServiceSettings.Domain == "testdomain.com" {
+		t.Fail()
+	}
+}