allow setting listen address via environment variable

poblahblahblah · poblahblahblah · commit ad176f752b01 · 2019-12-22T10:08:30.000-08:00
diff --git a/main.go b/main.go
@@ -75,6 +75,11 @@ func main() {
 		*password = pass
 	}
 
+    exporterAddr := os.Getenv("EXPORTER_ADDRESS")
+    if exporterAddr != "" {
+        *addr = exporterAddr
+    }
+
 	if *showVersion {
 		fmt.Printf("asprom %s\n", version)
 		os.Exit(0)
