program initial commit

src/main.rs

@@ -0,0 +1,114 @@
+use rppal::gpio::{Gpio, OutputPin};
+use serde::{Deserialize};
+use serde_json;
+use sqlite;
+use std::error::Error;
+use std::env;
+use std::fs::File;
+use std::path::Path;
+use std::thread;
+use std::time::Duration;
+
+// Gpio uses BCM pin numbering. BCM GPIO 23 is tied to physical pin 16.
+const GPIO_SWITCH: u8 = 24;
+
+// set duration of pin switching test
+const TEST_DURATION: u64 = 1000;
+
+#[derive(Deserialize)]
+#[derive(Debug)]
+struct Config{
+    database: String,
+    device_name_voltage: String,
+    voltage_off: f32,
+    voltage_recover: f32,
+}
+
+#[derive(Deserialize)]
+struct DbData{
+    V: String,
+}
+
+//fn main() {
+fn main () {
+    // read and parse configuration file
+    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 {
+        let action: &str = args[1].as_str();
+        match action {
+            "on" => pin_switch_on(),
+            "off" => pin_switch_off(),
+            "test" => pin_test(),
+            &_ => todo!("So far only the parameters 'on', 'off' and 'test' are supported.")
+        }
+    }
+    else { // no command line parameter set; check for voltages and switch the inverter accordingly
+        pin_status();
+        let voltage = get_current_voltage(&config);
+
+        if voltage < config.voltage_off && pin_status() > 0 {
+            println!("Siwtching off inverter due to low voltage!");
+            pin_switch_off();
+        }
+        else if voltage >= config.voltage_recover && pin_status() == 0 {
+            println!("Voltage recovered! Switching inverter back on.");
+            pin_switch_on();
+        }
+        else {
+            
+        }
+    }
+
+    //end program with OK status
+}
+
+fn pin_status () -> u8 {
+    let mut pin_level: u8 = Gpio::new().unwrap().get(GPIO_SWITCH).unwrap().read() as u8;
+    return pin_level;
+}
+
+fn pin_switch_on () {
+    let mut pin: OutputPin = Gpio::new().unwrap().get(GPIO_SWITCH).unwrap().into_output();
+    pin.set_reset_on_drop(false);
+    pin.set_high();
+}
+
+fn pin_switch_off () {
+    let mut pin: OutputPin = Gpio::new().unwrap().get(GPIO_SWITCH).unwrap().into_output();
+    pin.set_reset_on_drop(false);
+    pin.set_low();
+}
+
+fn pin_test () {
+    pin_switch_on();
+    thread::sleep(Duration::from_millis(TEST_DURATION));
+    pin_switch_off();
+}
+
+fn get_current_voltage (config: &Config) -> f32 {
+    let mut voltage: f32 = 0.0;
+    if !Path::new(&config.database).exists() {
+        return voltage;
+    }
+
+    let db_connection = sqlite::open(&config.database).unwrap();
+    let query = format!("SELECT data FROM '{device}' ORDER BY date DESC, time DESC LIMIT 1;", device = &config.device_name_voltage);
+
+    let _ = db_connection.iterate(query, |pairs | {
+        let data = pairs.get(0).unwrap().1.unwrap();
+        let test_parse: DbData = serde_json::from_str(data).expect("no proper JSON data found on database");
+        let raw_value = match test_parse.V.parse::<i32>() {
+            Ok(v) => v,
+            Err(_) => return true
+        };
+        voltage = raw_value as f32 / 1000.0;
+        true
+    });
+    return voltage;
+}