things

src/main.rs

@@ -1,26 +1,29 @@
 #![warn(rust_2018_idioms)]
 
 use anyhow::Result;
-use std::env;
+use clap::Parser;
 use tracing::{info, info_span, Instrument};
 
+/// An AMQP 0-9-1 broker implementation.
+#[derive(Parser)]
+struct Args {
+    /// Whether to serve the dashboard on localhost. Port defaults to 3000.
+    #[clap(short, long)]
+    dashboard: bool,
+    /// The log level of the application. Overwrites the `RUST_LOG` env var.
+    #[clap(long)]
+    log_level: Option<String>,
+}
+
 #[tokio::main]
 async fn main() -> Result<()> {
-    let mut dashboard = false;
+    let args = Args::parse();
 
-    for arg in env::args().skip(1) {
-        match arg.as_str() {
-            "--dashboard" => dashboard = true,
-            "ignore-this-clippy" => eprintln!("yes please"),
-            _ => {}
-        }
-    }
-
-    setup_tracing();
+    setup_tracing(&args);
 
     let global_data = amqp_core::GlobalData::default();
 
-    if dashboard {
+    if args.dashboard {
         let dashboard_span = info_span!("dashboard");
         tokio::spawn(amqp_dashboard::dashboard(global_data.clone()).instrument(dashboard_span));
     }
@@ -28,21 +31,22 @@ async fn main() -> Result<()> {
     amqp_transport::do_thing_i_guess(global_data).await
 }
 
-fn setup_tracing() {
+fn setup_tracing(args: &Args) {
     const DEFAULT_LOG: &str = "hyper=info,debug";
-    let rust_log = std::env::var("RUST_LOG");
+
+    let log_filter = args
+        .log_level
+        .clone()
+        .or_else(|| std::env::var("RUST_LOG").ok())
+        .unwrap_or_else(|| DEFAULT_LOG.to_owned());
 
     tracing_subscriber::fmt()
         .with_level(true)
         .with_timer(tracing_subscriber::fmt::time::time())
         .with_ansi(true)
         .with_thread_names(true)
-        .with_env_filter(rust_log.clone().unwrap_or_else(|_| DEFAULT_LOG.to_string()))
+        .with_env_filter(&log_filter)
         .init();
 
-    if let Ok(rust_log) = rust_log {
-        info!(%rust_log, "Using custom log level");
-    } else {
-        info!(%DEFAULT_LOG, "Using default log level");
-    }
+    info!(%log_filter, "Using log filter level");
 }