qemu-rdp: add -l option for logging

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

qemu-rdp/Cargo.toml

@@ -8,6 +8,8 @@ edition = "2021"
 
 [dependencies]
 qemu-display = { path = "../qemu-display" }
+tracing = "0.1.37"
+tracing-subscriber = { version = "0.3.16", features = ["env-filter"] }
 keycodemap = { path = "../keycodemap" }
 bytes = "1.4"
 rustls = { version = "0.21" }
@@ -15,6 +17,6 @@ rustls-pemfile = "1.0"
 tokio = { version = "1.28", features = ["full"] }
 tokio-rustls = "0.24"
 anyhow = "1.0"
-clap = { version = "3.2", features = ["derive"] }
+clap = { version = "4.2", features = ["derive", "cargo"] }
 async-trait = "0.1"
 ironrdp = { git = "https://github.com/Devolutions/IronRDP", features = ["server"] }

qemu-rdp/src/args.rs

@@ -1,5 +1,5 @@
 use clap::clap_derive::ValueEnum;
-use clap::Parser;
+use clap::{crate_name, Parser};
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, ValueEnum)]
 pub enum SecurityProtocol {
@@ -43,6 +43,9 @@ pub struct ServerArgs {
 
 #[derive(Parser, Debug)]
 pub struct Args {
+    #[clap(short, long, value_parser, default_value_t = format!("{}.log", crate_name!()))]
+    pub log_file: String,
+
     #[clap(flatten)]
     pub server: ServerArgs,
 

qemu-rdp/src/main.rs

@@ -1,3 +1,4 @@
+use anyhow::Context;
 use qemu_display::zbus;
 
 mod args;
@@ -7,6 +8,8 @@ mod server;
 async fn main() -> Result<(), anyhow::Error> {
     let mut args = args::parse();
 
+    setup_logging(args.log_file.as_str()).context("unable to initialize logging")?;
+
     let dbus = match args.dbus_address.take() {
         None => zbus::Connection::session().await,
         Some(addr) => {
@@ -21,3 +24,35 @@ async fn main() -> Result<(), anyhow::Error> {
 
     Ok(())
 }
+
+fn setup_logging(log_file: &str) -> anyhow::Result<()> {
+    use std::fs::OpenOptions;
+
+    use tracing::metadata::LevelFilter;
+    use tracing_subscriber::prelude::*;
+    use tracing_subscriber::EnvFilter;
+
+    let file = OpenOptions::new()
+        .create(true)
+        .append(true)
+        .open(log_file)
+        .with_context(|| format!("couldn’t open {log_file}"))?;
+
+    let fmt_layer = tracing_subscriber::fmt::layer()
+        .compact()
+        .with_ansi(false)
+        .with_writer(file);
+
+    let env_filter = EnvFilter::builder()
+        .with_default_directive(LevelFilter::WARN.into())
+        .with_env_var("QEMURDP_LOG_LEVEL")
+        .from_env_lossy();
+
+    tracing_subscriber::registry()
+        .with(fmt_layer)
+        .with(env_filter)
+        .try_init()
+        .context("failed to set tracing global subscriber")?;
+
+    Ok(())
+}