Add self update functionality

Signed-off-by: Jacob Kiers <code@kiers.eu>

src/main.rs

@@ -1,14 +1,33 @@
 mod config;
 mod servers;
+mod update;
 mod upstreams;
 
 use crate::config::ConfigV1;
 use crate::servers::Server;
 
 use log::{debug, error, info};
+use pico_args::Arguments;
 use std::path::PathBuf;
 
 fn main() {
+    let mut args = Arguments::from_env();
+
+    match args.subcommand().expect("Unexpected error").as_deref() {
+        Some("serve") => serve(),
+        Some("update") => update::update(),
+        Some(cmd) => {
+            eprintln!("Invalid command: {cmd}");
+            std::process::exit(1);
+        }
+        None => {
+            eprintln!("Calling l4p without argument is deprecated now. Please use: l4p serve");
+            serve();
+        }
+    }
+}
+
+fn serve() {
     let config_path = match find_config() {
         Ok(p) => p,
         Err(paths) => {

src/update.rs

@@ -0,0 +1,22 @@
+use self_update::{cargo_crate_version, version};
+
+pub(crate) fn update() {
+    println!("Updating to the latest version...");
+
+    let backend = self_update::backends::gitea::Update::configure()
+        .with_host("https://code.kiers.eu")
+        .repo_owner("jjkiers")
+        .repo_name("layer4-proxy")
+        .bin_name("l4p")
+        .show_download_progress(true)
+        .current_version(cargo_crate_version!())
+        .build()
+        .expect("Should initialize correctly.");
+
+    let status = backend.update_extended();
+
+    match status {
+        Err(e) => eprintln!("Error updating: {e}"),
+        Ok(_) => (),
+    }
+}