[Router] Add a rust-based router (#1790)

rust/src/main.rs

@@ -0,0 +1,28 @@
+// src/main.rs
+use clap::Parser;
+use clap::builder::PossibleValuesParser;
+// declare child modules
+mod server;
+mod router;
+
+#[derive(Parser, Debug)]
+#[command(author, version, about, long_about = None)]
+struct Args {
+    #[arg(long, default_value = "127.0.0.1")]
+    host: String,
+
+    #[arg(long, default_value_t = 3001)]
+    port: u16,
+
+    #[arg(long, value_delimiter = ',')]
+    worker_urls: Vec<String>,
+
+    #[arg(long, default_value = "round_robin", value_parser = PossibleValuesParser::new(&["round_robin", "random"]))]
+    policy: String,
+}
+
+#[actix_web::main]
+async fn main() -> std::io::Result<()> {
+    let args = Args::parse();
+    server::startup(args.host, args.port, args.worker_urls, args.policy).await
+}