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Initial protocol

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This commit is contained in:
cool-mist
2026-09-08 19:30:24 +05:30
parent 6a62c33f42
commit a3385e7702
9 changed files with 236 additions and 145 deletions
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Cargo.lock
Generated
+1
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@@ -23,6 +23,7 @@ version = "0.1.0"
dependencies = [
"hd-lib",
"tracing",
"tracing-subscriber",
]
[[package]]
crates/hd-client/Cargo.toml
+1
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@@ -6,3 +6,4 @@ edition = "2024"
[dependencies]
tracing = { workspace = true }
hd-lib = { path = "../hd-lib" }
tracing-subscriber = { version = "0.3", features = ["env-filter", "fmt"] }
crates/hd-client/src/bin/client.rs
+4
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@@ -1,6 +1,10 @@
use hd_client::{EventBusClient, EventBusClientError};
fn main() -> Result<(), EventBusClientError> {
tracing_subscriber::fmt()
.with_env_filter(tracing_subscriber::EnvFilter::from_default_env())
.init();
let addr = "0.0.0.0:21368";
let mut client = EventBusClient::start(addr)?;
client.subscribe()
crates/hd-client/src/lib.rs
+26 -30
View File
@@ -1,11 +1,22 @@
use std::{
io::{Read, Write},
net::TcpStream,
use std::net::TcpStream;
use hd_lib::{
bus::packet::{self, Packet, PacketType},
error::HError,
hd_tcp,
};
use tracing::{debug, info};
#[derive(Debug)]
pub enum EventBusClientError {
TcpStreamError(std::io::Error),
HError(HError),
}
impl From<HError> for EventBusClientError {
fn from(value: HError) -> Self {
Self::HError(value)
}
}
pub struct EventBusClient {
@@ -14,43 +25,28 @@ pub struct EventBusClient {
impl EventBusClient {
pub fn start(addr: &'static str) -> Result<Self, EventBusClientError> {
let stream = TcpStream::connect(addr).map_err(EventBusClientError::TcpStreamError)?;
println!("Event bus client connected to {}", addr);
let mut stream = TcpStream::connect(addr).map_err(EventBusClientError::TcpStreamError)?;
hd_tcp::write_packet(&mut stream, &Packet::create_connect_packet())?;
hd_tcp::read_ack(&mut stream, &[PacketType::Connect])?;
info!("Event bus client connected to {}", addr);
Ok(Self { tcp_stream: stream })
}
pub fn subscribe(&mut self) -> Result<(), EventBusClientError> {
let bytes = [1];
self.tcp_stream
.write_all(&bytes)
.map_err(EventBusClientError::TcpStreamError)?;
debug!("Going to subscribe");
hd_tcp::write_packet(&mut self.tcp_stream, &Packet::create_subscribe_packet(0))?;
hd_tcp::read_ack(&mut self.tcp_stream, &[PacketType::Subscribe])?;
self.tcp_stream.flush().map_err(EventBusClientError::TcpStreamError)?;
let mut buf = vec![0; 1024];
loop {
let Ok(bytes_read) = self.tcp_stream.read(&mut buf) else {
return Ok(());
};
if bytes_read == 0 {
eprintln!("Connection closed");
let packet = hd_tcp::read_packet(&mut self.tcp_stream)?;
if let Packet::Disconnect = packet {
info!("Disconnecting from the server");
return Ok(());
}
println!("MESSAGE BEGIN");
for b in &buf[0..bytes_read] {
print!("[{}] ", b);
}
println!("MESSAGE END");
// ACK
self.tcp_stream
.write_all(&bytes)
.map_err(EventBusClientError::TcpStreamError)?;
self.tcp_stream.flush().map_err(EventBusClientError::TcpStreamError)?;
debug!("Received packet ... {}", packet::get_packet_type(&packet));
hd_tcp::write_ack(&mut self.tcp_stream, PacketType::SendEvent)?;
}
}
}
crates/hd-lib/src/bus/mod.rs
+3 -2
View File
@@ -1,6 +1,6 @@
pub mod packet;
use tracing::{info, info_span};
use tracing::{debug_span, info, info_span};
use crate::error::HError;
use std::{
@@ -95,6 +95,7 @@ impl EventBus {
for s in &bus.subscription_handles {
if let Err(e) = s.new_event_signal.send(1) {
// TODO: Multiple failures should automatically unsubscribe
tracing::error!("Failed to notify {}", e);
}
}
@@ -195,7 +196,7 @@ impl Subscription {
fn start_delivery(mut subscription: Subscription, bus: EventBus) -> JoinHandle<Result<(), HError>> {
thread::spawn(move || {
loop {
let _scope = info_span!("subscription_delivery", subscription.id).entered();
let _scope = debug_span!("subscription_delivery", subscription.id).entered();
loop {
if let Ok(evt) = bus.get_next_event(subscription.cursor) {
info!("Delivering event {} ", evt.id);
crates/hd-lib/src/bus/packet.rs
+52 -24
View File
@@ -18,6 +18,23 @@ pub enum PacketType {
Disconnect,
}
impl Display for PacketType {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
let to_write = match self {
PacketType::Connect => "CONNECT",
PacketType::Subscribe => "SUBSCRIBE",
PacketType::Unsubscribe => "UNSUBSCRIBE",
PacketType::Publish => "PUBLISH",
PacketType::SendEvent => "SEND_EVENT",
PacketType::Settle => "SETTLE_EVENT",
PacketType::Ack => "ACK",
PacketType::Disconnect => "DISCONNECT",
};
write!(f, "{}", to_write)
}
}
pub enum Packet {
Connect,
Subscribe(SubscribePacket),
@@ -49,11 +66,15 @@ pub struct SettlePacket {
}
pub struct AckPacket {
packet_type: PacketType,
pub packet_type: PacketType,
}
impl Packet {
pub fn create_connect_packet(cursor: u64) -> Packet {
pub fn create_connect_packet() -> Packet {
Packet::Connect
}
pub fn create_subscribe_packet(cursor: u64) -> Packet {
Packet::Subscribe(SubscribePacket { cursor })
}
@@ -115,7 +136,7 @@ pub struct ReadPacketState {
pub fn start_read_packet(buf: &mut [u8; packet_constants::HEADER_SIZE]) -> Result<ReadPacketState, PacketError> {
let packet_type = get_packet_type_from_byte(buf[0])?;
let required_buffer_size = read_u16(&buf[1..3]);
let required_buffer_size = read_u16(&buf[1..3])?;
Ok(ReadPacketState {
required_buffer_size,
@@ -133,31 +154,29 @@ pub fn read_packet(buf: &[u8], read_state: ReadPacketState) -> Result<Packet, Pa
PacketType::Unsubscribe => Ok(Packet::Unsubscribe),
PacketType::Publish => {
let event_type = buf[0];
let len = read_u16(&buf[1..]);
let event_len = read_u16(&buf[1..3])?;
// TODO: Share underlying bytes without copying
let publish_packet = PublishPacket {
event_type,
data_utf8: buf[3..len].to_vec(),
data_utf8: buf[3..3 + event_len].to_vec(),
};
Ok(Packet::Publish(publish_packet))
}
PacketType::SendEvent => {
let event_id = read_u64(&buf)?;
let event_id = read_u64(&buf[0..8])?;
let event_type = buf[8];
let len = usize::from_le_bytes([buf[9], buf[10], 0, 0, 0, 0, 0, 0]);
let event_len = read_u16(&buf[9..11])?;
let send_event_packet = SendEventPacket {
event_id,
event_type,
data_utf8: buf[11..len].to_vec(),
data_utf8: buf[11..11 + event_len].to_vec(),
};
Ok(Packet::SendEvent(send_event_packet))
}
PacketType::Settle => {
let mut le_bytes = [0u8; 8];
le_bytes.copy_from_slice(&buf[0..8]);
let cursor = u64::from_le_bytes(le_bytes);
let cursor = read_u64(&buf[0..8])?;
Ok(Packet::Settle(SettlePacket { cursor }))
}
PacketType::Ack => {
@@ -214,7 +233,7 @@ fn write_data_frame(data_frame: &mut [u8], packet: &Packet) {
write_event_data(
send_event_packet.event_type,
&send_event_packet.data_utf8,
&mut data_frame[1..],
&mut data_frame[8..],
);
}
Packet::Settle(settle_packet) => {
@@ -231,12 +250,12 @@ fn write_event_data(event_type: u8, data_utf8: &[u8], buf: &mut [u8]) {
buf[0] = event_type;
write_u16(data_utf8.len(), &mut buf[1..3]);
let available_length = buf.len() - 3;
buf[3..].copy_from_slice(&data_utf8[..available_length]);
buf[3..].copy_from_slice(&data_utf8[0..available_length]);
}
fn write_u64(v64: u64, data_frame: &mut [u8]) {
let bytes = v64.to_le_bytes();
data_frame[0..8].copy_from_slice(&bytes);
data_frame[0..8].copy_from_slice(&bytes[0..8]);
}
fn write_u16(mut length: usize, buf: &mut [u8]) {
@@ -245,17 +264,25 @@ fn write_u16(mut length: usize, buf: &mut [u8]) {
}
let bytes = length.to_le_bytes();
buf[0..2].copy_from_slice(&bytes);
buf[0..2].copy_from_slice(&bytes[0..2]);
}
fn read_u64(buf: &[u8]) -> Result<u64, PacketError> {
let mut le_bytes = [0u8; 8];
if le_bytes.len() != buf.len() {
return Err(PacketError::PacketProtocolError);
}
le_bytes.copy_from_slice(buf);
Ok(u64::from_le_bytes(le_bytes))
}
fn read_u16(buf: &[u8]) -> usize {
usize::from_le_bytes([buf[0], buf[1], 0, 0, 0, 0, 0, 0])
fn read_u16(buf: &[u8]) -> Result<usize, PacketError> {
if buf.len() != 2 {
return Err(PacketError::PacketProtocolError);
}
Ok(usize::from_le_bytes([buf[0], buf[1], 0, 0, 0, 0, 0, 0]))
}
pub fn get_packet_type(packet: &Packet) -> PacketType {
@@ -286,13 +313,14 @@ fn get_byte_from_packet_type(packet_type: &PacketType) -> u8 {
fn get_packet_type_from_byte(byte: u8) -> Result<PacketType, PacketError> {
let packet_type = match byte {
0 => Some(PacketType::Subscribe),
1 => Some(PacketType::Unsubscribe),
2 => Some(PacketType::Publish),
3 => Some(PacketType::SendEvent),
4 => Some(PacketType::Settle),
5 => Some(PacketType::Ack),
6 => Some(PacketType::Disconnect),
0 => Some(PacketType::Connect),
1 => Some(PacketType::Subscribe),
2 => Some(PacketType::Unsubscribe),
3 => Some(PacketType::Publish),
4 => Some(PacketType::SendEvent),
5 => Some(PacketType::Settle),
6 => Some(PacketType::Ack),
7 => Some(PacketType::Disconnect),
_ => None,
};
crates/hd-lib/src/lib.rs
+60 -1
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@@ -1,3 +1,62 @@
pub mod bus;
pub mod error;
pub mod thread_pool;
pub mod bus;
pub mod hd_tcp {
use std::{
io::{Read, Write},
net::TcpStream,
};
use crate::{
bus::packet::{self, Packet, PacketType},
error::HError,
};
pub fn read_packet(stream: &mut TcpStream) -> Result<Packet, HError> {
let mut header_buf = [0u8; 3];
stream.read_exact(&mut header_buf)?;
let read_state = packet::start_read_packet(&mut header_buf)?;
let mut buf = vec![0u8; read_state.required_buffer_size];
if read_state.required_buffer_size > 0 {
stream.read_exact(&mut buf)?;
}
let packet = packet::read_packet(&buf[0..], read_state)?;
if let Packet::Disconnect = packet {
return Err(HError::PeerDisconnect);
};
Ok(packet)
}
pub fn read_ack(stream: &mut TcpStream, packet_types: &[PacketType]) -> Result<Packet, HError> {
let packet = read_packet(stream)?;
if let Packet::Ack(ack_packet) = &packet {
for packet_type in packet_types.iter() {
if *packet_type == ack_packet.packet_type {
return Ok(packet);
}
}
}
Err(HError::ProtocolError)
}
pub fn write_ack(stream: &mut TcpStream, packet_type: PacketType) -> Result<(), HError> {
let packet = Packet::create_ack_packet(packet_type);
write_packet(stream, &packet)
}
pub fn write_packet(stream: &mut TcpStream, packet: &Packet) -> Result<(), HError> {
let write_state = packet::start_write_packet(packet);
let mut buf = vec![0u8; write_state.required_buffer_size];
packet::write_packet(&mut buf, packet, write_state)?;
stream.write_all(&mut buf)?;
stream.flush()?;
Ok(())
}
}
crates/hd-server/src/bin/server.rs
+5 -2
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@@ -10,14 +10,17 @@ fn main() -> Result<(), HError> {
.init();
let addr = "0.0.0.0:21368";
let _scope = info_span!("example_server").entered();
let server = Arc::new(TcpEventBus::new());
server.publish(EventData::new(1, "Hello"))?;
server.publish(EventData::new(1, "World"))?;
let server_clone = server.clone();
thread::spawn(move || server.start(addr));
thread::spawn(move || {
let _scope = info_span!("tcp_server").entered();
server.start(addr)
});
let _scope = info_span!("health_checks").entered();
for i in 0..255 {
thread::sleep(Duration::from_secs(5));
server_clone.publish(EventData::new(i, "asd"))?;
crates/hd-server/src/lib.rs
+84 -86
View File
@@ -1,5 +1,4 @@
use std::{
io::{Read, Write},
net::TcpStream,
sync::{Arc, mpsc::Receiver},
time::Duration,
@@ -8,13 +7,14 @@ use std::{
use hd_lib::{
bus::{
Event, EventBus, EventData,
packet::{self, Packet, PacketType},
packet::{self, Packet, PacketType, PublishPacket, get_packet_type},
},
error::HError,
hd_tcp,
thread_pool::ThreadPool,
};
use tracing::{Span, info, info_span};
use tracing::{debug, error, info, info_span};
use std::net::TcpListener;
@@ -40,11 +40,11 @@ impl TcpEventBus {
impl TcpEventBus {
pub fn start(&self, addr: &'static str) -> Result<(), HError> {
let listener = TcpListener::bind(addr)?;
info!("Heimdall listening at {}", addr);
info!("Heimdall running at {}", addr);
for stream in listener.incoming() {
match stream {
Ok(stream) => handle_event_bus_client(&self.pool, self.bus.clone(), stream)?,
Err(e) => tracing::error!("TCP connection failed {}", e),
Err(e) => error!("TCP connection failed {}", e),
}
}
@@ -90,57 +90,11 @@ impl EventBusClientConnection {
}
}
fn read_ack(stream: &mut TcpStream, packet_type: PacketType) -> Result<(), HError> {
let packet = read_packet(stream)?;
if packet_type == packet::get_packet_type(&packet) {
return Ok(())
}
Err(HError::ProtocolError)
}
fn read_packet(stream: &mut TcpStream) -> Result<Packet, HError> {
let mut header_buf = [0u8; 3];
stream.read_exact(&mut header_buf)?;
let read_state = packet::start_read_packet(&mut header_buf)?;
let mut buf = vec![0u8; read_state.required_buffer_size];
stream.read_exact(&mut buf)?;
let packet = packet::read_packet(&buf[0..], read_state)?;
if let Packet::Disconnect = packet {
return Err(HError::PeerDisconnect);
};
Ok(packet)
}
fn write_ack(stream: &mut TcpStream, packet_type: PacketType) -> Result<(), HError> {
let packet = Packet::create_ack_packet(packet_type);
write_packet(stream, &packet)
}
fn write_packet(stream: &mut TcpStream, packet: &Packet) -> Result<(), HError> {
let write_state = packet::start_write_packet(packet);
let mut buf = vec![0u8; write_state.required_buffer_size];
packet::write_packet(&mut buf, packet, write_state)?;
stream.write_all(&mut buf)?;
stream.flush()?;
Ok(())
}
pub fn handle_event_bus_client(thread_pool: &ThreadPool, bus: EventBus, stream: TcpStream) -> Result<(), HError> {
thread_pool.execute(move || {
let mut client = EventBusClientConnection::new(bus, stream)?;
let _scope = info_span!(
"handle_event_bus_client",
addr = client.addr,
state = %client.state
)
.entered();
let _scope = info_span!("handle_client", addr = client.addr,).entered();
loop {
if let EventBusClientConnectionState::Disconnect = client.state {
@@ -154,8 +108,6 @@ pub fn handle_event_bus_client(thread_pool: &ThreadPool, bus: EventBus, stream:
if prev_state != client.state {
info!("State change {} -> {}", prev_state, client.state);
}
Span::current().record("state", format!("{}", client.state));
}
})
}
@@ -163,7 +115,7 @@ pub fn handle_event_bus_client(thread_pool: &ThreadPool, bus: EventBus, stream:
fn handle_event_bus_client_state(client: &mut EventBusClientConnection) -> Result<(), HError> {
let next_state = match client.state {
EventBusClientConnectionState::Connect => handle_state_connect(client),
EventBusClientConnectionState::Command => handle_state_connect(client),
EventBusClientConnectionState::Command => handle_state_command(client),
EventBusClientConnectionState::SendEvent => handle_state_send_event(client),
EventBusClientConnectionState::WaitEvent => handle_state_wait_event(client),
EventBusClientConnectionState::Disconnect => Ok(EventBusClientConnectionState::Disconnect),
@@ -174,66 +126,112 @@ fn handle_event_bus_client_state(client: &mut EventBusClientConnection) -> Resul
}
fn handle_state_connect(client: &mut EventBusClientConnection) -> Result<EventBusClientConnectionState, HError> {
let Packet::Connect = read_packet(&mut client.stream)? else {
return Ok(EventBusClientConnectionState::Disconnect);
};
match hd_tcp::read_packet(&mut client.stream)? {
Packet::Connect => {
info!("Received connect, acking");
write_ack(&mut client.stream, PacketType::Connect)?;
Ok(EventBusClientConnectionState::Command)
hd_tcp::write_ack(&mut client.stream, PacketType::Connect)?;
info!("Connect ack complete");
Ok(EventBusClientConnectionState::Command)
}
p => {
error!(
"Received wrong packet of type {}, expected {}. Will disconnect",
get_packet_type(&p),
PacketType::Connect
);
Ok(EventBusClientConnectionState::Disconnect)
}
}
}
fn handle_state_command(client: &mut EventBusClientConnection) -> Result<EventBusClientConnectionState, HError> {
match read_packet(&mut client.stream)? {
match hd_tcp::read_packet(&mut client.stream)? {
// TODO: Read cursor
Packet::Subscribe(_) => {
write_ack(&mut client.stream, PacketType::Subscribe)?;
info!("Received subscribe");
let subscription = client.bus.subscribe()?;
info!("Subscribed to the event bus");
client.subscription = Some(subscription);
// TODO: Return error if any
hd_tcp::write_ack(&mut client.stream, PacketType::Subscribe)?;
info!("Subscribe ack complete");
Ok(EventBusClientConnectionState::SendEvent)
}
Packet::Publish(publish_packet) => {
write_ack(&mut client.stream, PacketType::Publish)?;
info!("Received publish packet");
publish_packet_to_bus(client, publish_packet)?;
// TODO: Possible without copying data_utf8?
let data = String::from_utf8(publish_packet.data_utf8)?;
client.bus.publish(EventData::new(publish_packet.event_type, &data))?;
// TODO: Return error if any
hd_tcp::write_ack(&mut client.stream, PacketType::Publish)?;
debug!("Publish ack complete");
Ok(EventBusClientConnectionState::WaitEvent)
}
_ => Ok(EventBusClientConnectionState::Disconnect),
p => {
error!(
"Received wrong packet of type {}, expected {}. Will disconnect",
get_packet_type(&p),
PacketType::Connect
);
Ok(EventBusClientConnectionState::Disconnect)
}
}
}
fn handle_state_send_event(client: &mut EventBusClientConnection) -> Result<EventBusClientConnectionState, HError> {
if let Some(subscription) = &mut client.subscription {
loop {
let Ok(evt) = subscription.recv() else {
return Ok(EventBusClientConnectionState::Disconnect);
};
// TODO: When client sends unsubscribe, server shouldn't take forever
// to ack that.
let Ok(evt) = subscription.recv() else {
error!("Failed to receive a message for this subscription, disconnecting");
return Ok(EventBusClientConnectionState::Disconnect);
};
info!(
"SEND => ID: {} TYPE: {} LEN: {} <=",
evt.id,
evt.data.event_type,
evt.data.data_utf8.len()
);
let packet = Packet::create_send_event_packet(evt);
hd_tcp::write_packet(&mut client.stream, &packet)?;
debug!("Published event to client, waiting for ack");
let packet = Packet::create_send_event_packet(evt);
write_packet(&mut client.stream, &packet)?;
read_ack(&mut client.stream, PacketType::SendEvent)?;
let ack_packet = hd_tcp::read_ack(&mut client.stream, &[PacketType::SendEvent, PacketType::Unsubscribe])?;
if packet::get_packet_type(&ack_packet) == PacketType::Unsubscribe {
info!("Subscriber unsubscribed");
return Ok(EventBusClientConnectionState::Command);
}
debug!("Publish ack received, message is settled");
}
Ok(EventBusClientConnectionState::Disconnect)
Ok(EventBusClientConnectionState::SendEvent)
}
fn handle_state_wait_event(client: &mut EventBusClientConnection) -> Result<EventBusClientConnectionState, HError> {
todo!()
match hd_tcp::read_packet(&mut client.stream)? {
Packet::Publish(publish_packet) => {
debug!("Received event from client, publishing to bus");
publish_packet_to_bus(client, publish_packet)?;
hd_tcp::write_ack(&mut client.stream, PacketType::Publish)?;
debug!("Ack receive event complete");
Ok(EventBusClientConnectionState::WaitEvent)
}
p => {
error!(
"Received wrong packet of type {}, expected {}. Will disconnect",
get_packet_type(&p),
PacketType::Connect
);
Ok(EventBusClientConnectionState::Disconnect)
}
}
}
fn write_le_bytes(v64: u64, buf: &mut [u8]) {
let le_bytes = v64.to_le_bytes();
buf[0..8].copy_from_slice(&le_bytes);
fn publish_packet_to_bus(client: &mut EventBusClientConnection, packet: PublishPacket) -> Result<(), HError> {
let data = String::from_utf8(packet.data_utf8)?;
let evt = EventData::new(packet.event_type, &data);
client.bus.publish(evt)?;
Ok(())
}
impl std::fmt::Display for EventBusClientConnectionState {