added command line option to customize the configuration file path

src/main.rs

@@ -30,25 +30,30 @@ struct DbData{
 
 //fn main() {
 fn main () {
-    // read and parse configuration file
+    let mut config_file_path = "~/.isolated-switches/config.json";
-    let config_file = File::open("config.json")
-        .expect("file should open read only");
-    let config: Config = serde_json::from_reader(config_file)
-        .expect("file should be proper JSON");
 
     // read and parse command line parameters
     let args: Vec<String> = env::args().collect();
-    if args.len() >= 2 {
+    for n in 1..args.len() {
-        let action: &str = args[1].as_str();
+        match args[n].as_str() {
-        match action {
+            "on" => {
-            "on" => pin_switch_on(),
+                pin_switch_on();
-            "off" => pin_switch_off(),
+                return;
+            },
+            "off" => { 
+                pin_switch_off();
+                return;
+            },
             "status" => println!("Inverter status: {}" , if pin_status() == 0 { "off" } else { "on" }),
-            "test" => pin_test(&config),
+            "test" => pin_test(config_file_path),
-            _ => println!("So far only the parameters 'on', 'off', status and 'test' are supported.")
+            "config" => {
+                if args.len() > n + 1 { config_file_path = args[n + 1].as_str(); }
+            },
+            _ => ()
         }
     }
-    else { // no command line parameter set; check for voltages and switch the inverter accordingly
+
+    let config: Config = read_config(&config_file_path);
     let pin_status_cur = pin_status();
     let voltage = get_current_voltage(&config);
 
@@ -65,11 +70,19 @@ fn main () {
         let pin_status_text = if pin_status_cur == 0 { "off" } else { "on" };
         println!("No change in inverter status. Current status: {}", pin_status_text);
     }
-    }
 
     //end program with OK status
 }
 
+// read and parse configuration file
+fn read_config(config_file_path: &str) -> Config {
+    let config_file = File::open(&config_file_path)
+        .expect("Could not read config file");
+    let config: Config = serde_json::from_reader(config_file)
+        .expect("file should be proper JSON");
+    config
+}
+
 fn pin_status () -> u8 {
     let pin_level: u8 = Gpio::new().unwrap().get(GPIO_SWITCH).unwrap().read() as u8;
     return pin_level;
@@ -89,7 +102,8 @@ fn pin_switch_off () {
     println!("Inverter switched off.");
 }
 
-fn pin_test (config: &Config) {
+fn pin_test (config_path: &str) {
+    let config: Config = read_config(&config_path);
     pin_switch_on();
     thread::sleep(Duration::from_millis(config.test_duration_seconds * 1000));
     pin_switch_off();