tsmon: read hostname and region from config file

common/tsmon/iface.go

Index: common/tsmon/iface.go
diff --git a/common/tsmon/iface.go b/common/tsmon/iface.go
index 90559043aec0eb76fb554a9a685b9e45b0d6cb32..25d85f862ad370eb3db944f1d643c3867d5eef95 100644
--- a/common/tsmon/iface.go
+++ b/common/tsmon/iface.go
@@ -99,6 +99,22 @@ func InitializeFromFlags(c context.Context, fl *Flags) error {
 	if config.AutoGenHostname {
 		fl.Target.AutoGenHostname = true
 	}
+	if config.Hostname != "" {
+		if fl.Target.DeviceHostname == "" {
+			fl.Target.DeviceHostname = config.Hostname
+		}
+		if fl.Target.TaskHostname == "" {
+			fl.Target.TaskHostname = config.Hostname
+		}
+	}
+	if config.Region != "" {
+		if fl.Target.DeviceRegion == "" {
+			fl.Target.DeviceRegion = config.Region
+		}
+		if fl.Target.TaskRegion == "" {
+			fl.Target.TaskRegion = config.Region
+		}
+	}
 	fl.Target.SetDefaultsFromHostname()
 	t, err := target.NewFromFlags(&fl.Target)
 	if err != nil {