add support for getting a user name from config

internal/resource/user.go

@@ -182,6 +182,11 @@ func (u *User) UseConfig(config data.ConfigurationValueGetter) {
 }
 
 func (u *User) ResolveId(ctx context.Context) string {
+	if u.config != nil {
+		if configUser, configUserErr := u.config.GetValue("user"); configUserErr == nil && u.Name == "" {
+			u.Name = configUser.(string)
+		}
+	}
 	return LookupUIDString(u.Name)
 }
 

internal/resource/user_test.go

@@ -13,6 +13,7 @@ import (
 	_ "os"
 	_ "strings"
 	"testing"
+	"decl/internal/data"
 )
 
 func TestNewUserResource(t *testing.T) {
@@ -77,3 +78,22 @@ func TestCreateUser(t *testing.T) {
 	applyDeleteErr := u.Apply()
 	assert.Equal(t, nil, applyDeleteErr)
 }
+
+func TestSystemUser(t *testing.T) {
+	u := NewUser()
+
+	u.UseConfig(MockConfigValueGetter(func(key string) (any, error) {
+		switch key {
+		case "user":
+			return "bar", nil
+		case "group":
+			return "foo", nil
+		case "uid":
+			return "", nil
+		}
+		return nil, fmt.Errorf("%w: %s", data.ErrUnknownConfigurationKey, key)
+	}))
+
+	u.ResolveId(context.Background())
+	assert.Equal(t, "bar", u.Name)
+}