add server restart support w/ admin command

Signed-off-by: Jason Volk <jason@zemos.net>

src/admin/server/mod.rs

@@ -49,6 +49,10 @@ pub(crate) enum ServerCommand {
 	/// - Hot-reload the server
 	Reload,
 
+	#[cfg(unix)]
+	/// - Restart the server
+	Restart,
+
 	/// - Shutdown the server
 	Shutdown,
 }
@@ -72,6 +76,8 @@ pub(crate) async fn process(command: ServerCommand, body: Vec<&str>) -> Result<R
 		} => admin_notice(body, message).await?,
 		#[cfg(conduit_mods)]
 		ServerCommand::Reload => reload(body).await?,
+		#[cfg(unix)]
+		ServerCommand::Restart => restart(body).await?,
 		ServerCommand::Shutdown => shutdown(body).await?,
 	})
 }

src/admin/server/server_commands.rs

@@ -112,6 +112,13 @@ pub(crate) async fn reload(_body: Vec<&str>) -> Result<RoomMessageEventContent>
 	Ok(RoomMessageEventContent::notice_plain("Reloading server..."))
 }
 
+#[cfg(unix)]
+pub(crate) async fn restart(_body: Vec<&str>) -> Result<RoomMessageEventContent> {
+	services().server.restart()?;
+
+	Ok(RoomMessageEventContent::notice_plain("Restarting server..."))
+}
+
 pub(crate) async fn shutdown(_body: Vec<&str>) -> Result<RoomMessageEventContent> {
 	warn!("shutdown command");
 	services().server.shutdown()?;

src/core/server.rs

@@ -23,6 +23,9 @@ pub struct Server {
 	/// is an observable used on shutdown and modifying is not recommended.
 	pub reloading: AtomicBool,
 
+	/// Restart desired; when true, restart it desired after shutdown.
+	pub restarting: AtomicBool,
+
 	/// Handle to the runtime
 	pub runtime: Option<runtime::Handle>,
 
@@ -48,6 +51,7 @@ impl Server {
 			started: SystemTime::now(),
 			stopping: AtomicBool::new(false),
 			reloading: AtomicBool::new(false),
+			restarting: AtomicBool::new(false),
 			runtime,
 			signal: broadcast::channel::<&'static str>(1).0,
 			log,
@@ -75,6 +79,14 @@ impl Server {
 		self.signal("SIGINT")
 	}
 
+	pub fn restart(&self) -> Result<()> {
+		if self.restarting.swap(true, Ordering::AcqRel) {
+			return Err(Error::Err("Restart already in progress".into()));
+		}
+
+		self.shutdown()
+	}
+
 	pub fn shutdown(&self) -> Result<()> {
 		if self.stopping.swap(true, Ordering::AcqRel) {
 			return Err(Error::Err("Shutdown already in progress".into()));

src/main/main.rs

@@ -1,11 +1,16 @@
 pub(crate) mod clap;
 mod mods;
+mod restart;
 mod server;
 mod signal;
 
 extern crate conduit_core as conduit;
 
-use std::{cmp, sync::Arc, time::Duration};
+use std::{
+	cmp,
+	sync::{atomic::Ordering, Arc},
+	time::Duration,
+};
 
 use conduit::{debug_info, error, utils::available_parallelism, Error, Result};
 use server::Server;
@@ -32,8 +37,13 @@ fn main() -> Result<(), Error> {
 
 	// explicit drop here to trace thread and tls dtors
 	drop(runtime);
-	debug_info!("Exit");
 
+	#[cfg(unix)]
+	if server.server.restarting.load(Ordering::Acquire) {
+		restart::restart();
+	}
+
+	debug_info!("Exit");
 	Ok(())
 }
 

src/main/restart.rs

@@ -0,0 +1,17 @@
+#![cfg(unix)]
+
+use std::{env, os::unix::process::CommandExt, process::Command};
+
+use conduit::{debug, info};
+
+pub(super) fn restart() -> ! {
+	let exe = env::current_exe().expect("program path must be identified and available");
+	let envs = env::vars();
+	let args = env::args().skip(1);
+	debug!(?exe, ?args, ?envs, "Restart");
+
+	info!("Restart");
+
+	let error = Command::new(exe).args(args).envs(envs).exec();
+	panic!("{error:?}");
+}