add some basic config file parsing

src/monitor.rs

@@ -0,0 +1,34 @@
+use serde::Deserialize;
+use std::fs;
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum Error {
+    #[error("io error")]
+    IoError(#[from] std::io::Error),
+    #[error("toml parsing error")]
+    ParseError(#[from] toml::de::Error),
+}
+
+#[derive(Deserialize)]
+pub struct MonitorConfig {
+    target: Vec<String>,
+}
+impl MonitorConfig {
+    fn print(&self) {
+        for t in &self.target {
+            println!("* {}", t);
+        }
+    }
+}
+
+pub struct Monitor {}
+
+impl Monitor {
+    pub fn new_from_file(config_file: &str) -> Result<Self, Error> {
+        let config_str = fs::read_to_string(config_file)?;
+        let config: MonitorConfig = toml::from_str(&config_str)?;
+        config.print();
+        Ok(Self {})
+    }
+}