use std::{ffi::OsStr, path::PathBuf, sync::Arc};
use color_eyre::{
Result,
eyre::{Context, eyre},
};
use dashmap::DashMap;
use pty_process::{Command, Pty};
use tokio::{
fs,
io::{self, AsyncBufReadExt, AsyncReadExt, AsyncWriteExt, BufReader},
net::{TcpListener, UnixListener},
process::Child,
select,
sync::{
broadcast,
mpsc::{UnboundedReceiver, UnboundedSender, unbounded_channel},
oneshot,
},
};
use crate::{
config::{self, Config},
consts::{LOCAL_TCP_ADDR, MAX_MESSAGE_LENGTH, SOCKET_PATH},
line_buffer::LineBuffer,
messages::{ClientMessage, ServerMessage},
metadata, read_message,
server::types::{Request, ServerCommunicator},
write_message,
};
async fn spawn_server_process(
config: &'static Config,
name: &str,
flags: &[impl AsRef<OsStr>],
) -> Result<(Pty, Child)> {
let (pty, pts) = pty_process::open()?;
pty.resize(pty_process::Size::new(24, 80))?;
let mut server_dir = PathBuf::from(config.servers_directory.to_string());
server_dir.push(name);
let child = Command::new("java")
.arg("-jar")
.arg(metadata::get_jar_file(server_dir.clone()).await?)
.args(flags)
.current_dir(server_dir)
.spawn(pts)?;
Ok((pty, child))
}
async fn start_server(
config: &'static Config,
name: &str,
mut message_receiver: UnboundedReceiver<ClientMessage>,
mut request_receiver: UnboundedReceiver<Request>,
sender: broadcast::Sender<ServerMessage>,
) -> Result<()> {
let mut history: LineBuffer<Vec<u8>> = LineBuffer::new();
let (mut pty, mut child) = spawn_server_process(config, name, &config.default_java_args)
.await
.wrap_err("Failed to spawn server process")?;
let mut stdout_finished = false;
loop {
let mut stdout_buf = [0u8; 1024];
select! {
res = child.wait() => {
res?;
break;
},
res = pty.read(&mut stdout_buf), if !stdout_finished => {
let count = res?;
if count == 0 {
stdout_finished = true;
continue;
}
let bytes_read = &stdout_buf[..count];
history.push(bytes_read.to_owned());
let _ = sender.send(ServerMessage::Output(bytes_read.to_owned()));
continue;
}
message = message_receiver.recv() => {
let Some(message) = message else {
continue;
};
match message {
ClientMessage::Attach { name } => {
eprintln!("Tried attaching to {name} (does not work here)");
},
ClientMessage::Detach => {
eprintln!("Tried detaching (does not work here)");
},
ClientMessage::Kill => {
match child.kill().await {
Ok(()) => {
sender.send(ServerMessage::KillSuccess)?;
break;
}
Err(err) => {
sender.send(ServerMessage::KillFailure(err.to_string()))?;
return Err(eyre!("Failed to kill server"));
}
};
}
ClientMessage::ProgramInput(bytes) => {
history.push(bytes.clone());
pty.write_all(&bytes).await?;
}
}
}
request = request_receiver.recv() => {
let Some(request) = request else {
continue;
};
let _ = match request {
Request::GetHistory(sender) => sender.send(history.clone()).inspect_err(|_| eprintln!("Failed to send history")),
};
}
};
}
Ok(())
}
async fn server_lifecycle(
config: &'static Config,
name: String,
message_receiver: UnboundedReceiver<ClientMessage>,
request_receiver: UnboundedReceiver<Request>,
sender: broadcast::Sender<ServerMessage>,
server_communicators: Arc<DashMap<String, ServerCommunicator>>,
) -> Result<()> {
println!("Starting {name}");
let res = start_server(config, &name, message_receiver, request_receiver, sender).await;
if let Err(err) = &res {
eprintln!("Server: {name} btwwwwww\n{err:?}");
}
server_communicators.remove(&name);
println!("Server {name} closed");
res
}
enum ServeAction {
Prompt,
Attach(String),
}
async fn initialize_server(
config: &'static Config,
name: String,
server_communicators: &Arc<DashMap<String, ServerCommunicator>>,
) -> Result<(
UnboundedSender<ClientMessage>,
UnboundedSender<Request>,
broadcast::Receiver<ServerMessage>,
)> {
let (client_message_sender, client_message_receiver) = unbounded_channel();
let (client_request_sender, client_request_receiver) = unbounded_channel();
let (server_message_sender, server_message_receiver) = broadcast::channel(4096);
server_communicators.insert(
name.clone(),
ServerCommunicator {
client_message_sender: client_message_sender.clone(),
client_request_sender: client_request_sender.clone(),
server_message_sender: server_message_sender.clone(),
},
);
tokio::spawn(server_lifecycle(
config,
name,
client_message_receiver,
client_request_receiver,
server_message_sender.clone(),
server_communicators.clone(),
));
Ok((
client_message_sender,
client_request_sender,
server_message_receiver,
))
}
async fn serve_client(
(mut reader, mut writer): (impl AsyncReadExt + Unpin, impl AsyncWriteExt + Unpin),
config: &'static Config,
server_communicators: &Arc<DashMap<String, ServerCommunicator>>,
) -> Result<()> {
#[allow(unreachable_code)]
let mut action = ServeAction::Prompt;
loop {
match action {
ServeAction::Prompt => {
let name = &loop {
let message: ClientMessage = match read_message!(reader).await {
Ok(message) => message,
Err(crate::error::Error::Io(err))
if err.kind() == io::ErrorKind::UnexpectedEof =>
{
println!("Most graceful client disconnect");
return Ok(());
}
Err(err) => return Err(err).wrap_err("Erroneous client disconnect"),
};
match message {
ClientMessage::Attach { name } => break name,
_ => {
write_message!(writer, ServerMessage::NotAttached).await?;
println!("Not attached but received {message}!");
}
};
};
action = ServeAction::Attach(name.to_owned());
}
ServeAction::Attach(name) => {
let (message_sender, requets_sender, mut receiver) =
match server_communicators.get(&name) {
Some(com) => (
com.client_message_sender.clone(),
com.client_request_sender.clone(),
com.server_message_sender.subscribe(),
),
None => initialize_server(config, name, server_communicators).await?,
};
let (tx, rx) = oneshot::channel();
requets_sender.send(Request::GetHistory(tx))?;
let history = rx.await.unwrap_or_else(|err| {
LineBuffer::from(vec![
format!("Falied to produce history: {err:?}\n").into_bytes(),
])
});
write_message!(writer, ServerMessage::History(history)).await?;
action = loop {
select! {
res = receiver.recv() => {
let message = match res {
Ok(message) => message,
Err(broadcast::error::RecvError::Closed) => {
write_message!(writer, ServerMessage::Closed).await?;
break ServeAction::Prompt;
},
Err(broadcast::error::RecvError::Lagged(messages)) => {
eprintln!("Missed {messages} messages");
continue;
},
};
write_message!(writer, message).await?;
}
res = reader.read_u32() => {
let size = match res {
Ok(n) => n as usize,
Err(err) if err.kind() == io::ErrorKind::UnexpectedEof => {
println!("Graceful disconnect!!");
return Ok(());
}
Err(err) => return Err(err).wrap_err("Failed to read message size"),
};
if size > MAX_MESSAGE_LENGTH {
eprintln!("The client is being very disingenuous right now!! I'm going to have to break up with them unfortunately");
return Err(eyre!("Disingenuous client"));
}
let message: ClientMessage = read_message!(reader, size).await?;
match message {
ClientMessage::Attach { name } => break ServeAction::Attach(name),
ClientMessage::Detach => break ServeAction::Prompt,
ClientMessage::Kill | ClientMessage::ProgramInput(..) => message_sender.send(message)?,
}
}
}
}
}
}
}
}
pub async fn main() -> Result<()> {
let config: &'static Config = Box::leak(Box::new(
config::read().await.wrap_err("Failed to read config")?.0,
));
if let Err(err) = fs::remove_file(SOCKET_PATH).await
&& err.kind() != io::ErrorKind::NotFound
{
return Err(err).wrap_err("Failed to remove socket file");
}
let tcp_listener = TcpListener::bind(LOCAL_TCP_ADDR).await?;
println!("Bound to TCP address!");
let unix_sock_listener = UnixListener::bind(SOCKET_PATH)?;
println!("Bound to unix socket!");
let server_communicators: Arc<DashMap<String, ServerCommunicator>> = Arc::new(DashMap::new());
let mut buf = String::new();
let mut stdin_finished = false;
let mut stdin_reader = BufReader::new(io::stdin());
loop {
select! {
res = tcp_listener.accept() => {
let server_communicators = server_communicators.clone();
tokio::spawn(async move {
let (mut stream, addr) = res?;
println!("Connected to client by tcp: {addr}");
if let Err(err) = serve_client(stream.split(), config, &server_communicators).await {
eprintln!("{err:?}");
}
io::Result::Ok(())
});
},
res = unix_sock_listener.accept() => {
let server_communicators = server_communicators.clone();
tokio::spawn(async move {
let (mut stream, addr) = res?;
println!("Connected to client by unix socket: {addr:?}");
if let Err(err) = serve_client(stream.split(), config, &server_communicators).await {
eprintln!("{err:?}");
}
io::Result::Ok(())
});
}
res = stdin_reader.read_line(&mut buf), if !stdin_finished => {
res?;
if buf.is_empty() {
stdin_finished = true;
continue;
}
match &buf[..buf.len()-1] {
"stop" => {
println!("OK, stopping");
break;
}
_ => eprintln!("I don't understand"),
}
}
};
}
println!("Closing now...");
Ok(())
}