aboutsummaryrefslogtreecommitdiff
path: root/src/client.rs
blob: 0dcbdf17bc23a4479af9cc635906a5e620ec479c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
use std::collections::HashMap;
use std::net::SocketAddr;
use std::sync::atomic::{self, AtomicU32};
use std::sync::{Arc, Mutex};

use arc_swap::ArcSwapOption;
use async_trait::async_trait;
use bytes::Bytes;
use log::{debug, error, trace};

use futures::io::AsyncReadExt;
use kuska_handshake::async_std::{handshake_client, BoxStream};
use tokio::net::TcpStream;
use tokio::select;
use tokio::sync::{mpsc, oneshot, watch};
use tokio_util::compat::*;

#[cfg(feature = "telemetry")]
use opentelemetry::{
	trace::{FutureExt, Span, SpanKind, TraceContextExt, Tracer},
	Context, KeyValue,
};
#[cfg(feature = "telemetry")]
use opentelemetry_contrib::trace::propagator::binary::*;

use crate::error::*;
use crate::message::*;
use crate::netapp::*;
use crate::recv::*;
use crate::send::*;
use crate::stream::*;
use crate::util::*;

pub(crate) struct ClientConn {
	pub(crate) remote_addr: SocketAddr,
	pub(crate) peer_id: NodeID,

	query_send: ArcSwapOption<mpsc::UnboundedSender<(RequestID, RequestPriority, ByteStream)>>,

	next_query_number: AtomicU32,
	inflight: Mutex<HashMap<RequestID, oneshot::Sender<ByteStream>>>,
}

impl ClientConn {
	pub(crate) async fn init(
		netapp: Arc<NetApp>,
		socket: TcpStream,
		peer_id: NodeID,
	) -> Result<(), Error> {
		let remote_addr = socket.peer_addr()?;
		let mut socket = socket.compat();

		// Do handshake to authenticate and prove our identity to server
		let handshake = handshake_client(
			&mut socket,
			netapp.netid.clone(),
			netapp.id,
			netapp.privkey.clone(),
			peer_id,
		)
		.await?;

		debug!(
			"Handshake complete (client) with {}@{}",
			hex::encode(&peer_id),
			remote_addr
		);

		// Create BoxStream layer that encodes content
		let (read, write) = socket.split();
		let (mut read, write) =
			BoxStream::from_handshake(read, write, handshake, 0x8000).split_read_write();

		// Before doing anything, receive version tag and
		// check they are running the same version as us
		let mut their_version_tag = VersionTag::default();
		read.read_exact(&mut their_version_tag[..]).await?;
		if their_version_tag != netapp.version_tag {
			let msg = format!(
				"different version tags: {} (theirs) vs. {} (ours)",
				hex::encode(their_version_tag),
				hex::encode(netapp.version_tag)
			);
			error!("Cannot connect to {}: {}", hex::encode(&peer_id[..8]), msg);
			return Err(Error::VersionMismatch(msg));
		}

		// Build and launch stuff that manages sending requests client-side
		let (query_send, query_recv) = mpsc::unbounded_channel();

		let (stop_recv_loop, stop_recv_loop_recv) = watch::channel(false);

		let conn = Arc::new(ClientConn {
			remote_addr,
			peer_id,
			next_query_number: AtomicU32::from(RequestID::default()),
			query_send: ArcSwapOption::new(Some(Arc::new(query_send))),
			inflight: Mutex::new(HashMap::new()),
		});

		netapp.connected_as_client(peer_id, conn.clone());

		tokio::spawn(async move {
			let send_future = tokio::spawn(conn.clone().send_loop(query_recv, write));

			let conn2 = conn.clone();
			let recv_future = tokio::spawn(async move {
				select! {
					r = conn2.recv_loop(read) => r,
					_ = await_exit(stop_recv_loop_recv) => Ok(())
				}
			});

			send_future.await.log_err("ClientConn send_loop");

			// FIXME: should do here: wait for inflight requests to all have their response
			stop_recv_loop
				.send(true)
				.log_err("ClientConn send true to stop_recv_loop");

			recv_future.await.log_err("ClientConn recv_loop");

			// Make sure we don't wait on any more requests that won't
			// have a response
			conn.inflight.lock().unwrap().clear();

			netapp.disconnected_as_client(&peer_id, conn);
		});

		Ok(())
	}

	pub fn close(&self) {
		self.query_send.store(None);
	}

	pub(crate) async fn call<T>(
		self: Arc<Self>,
		req: Req<T>,
		path: &str,
		prio: RequestPriority,
	) -> Result<Resp<T>, Error>
	where
		T: Message,
	{
		let query_send = self.query_send.load_full().ok_or(Error::ConnectionClosed)?;

		let id = self
			.next_query_number
			.fetch_add(1, atomic::Ordering::Relaxed);

		cfg_if::cfg_if! {
			if #[cfg(feature = "telemetry")] {
				let tracer = opentelemetry::global::tracer("netapp");
				let mut span = tracer.span_builder(format!("RPC >> {}", path))
					.with_kind(SpanKind::Client)
					.start(&tracer);
				let propagator = BinaryPropagator::new();
				let telemetry_id: Bytes = propagator.to_bytes(span.span_context()).to_vec().into();
			} else {
				let telemetry_id: Bytes = Bytes::new();
			}
		};

		// Encode request
		let req_enc = req.into_enc(prio, path.as_bytes().to_vec().into(), telemetry_id);
		let req_msg_len = req_enc.msg.len();
		let req_stream = req_enc.encode();

		// Send request through
		let (resp_send, resp_recv) = oneshot::channel();
		let old = self.inflight.lock().unwrap().insert(id, resp_send);
		if let Some(old_ch) = old {
			error!(
				"Too many inflight requests! RequestID collision. Interrupting previous request."
			);
			let _ = old_ch.send(Box::pin(futures::stream::once(async move {
				Err(std::io::Error::new(std::io::ErrorKind::Other, "RequestID collision, too many inflight requests"))
			})));
		}

		debug!(
			"request: query_send {}, path {}, prio {} (serialized message: {} bytes)",
			id, path, prio, req_msg_len
		);

		#[cfg(feature = "telemetry")]
		span.set_attribute(KeyValue::new("len_query_msg", req_msg_len as i64));

		query_send.send((id, prio, req_stream))?;

		cfg_if::cfg_if! {
			if #[cfg(feature = "telemetry")] {
				let stream = resp_recv
					.with_context(Context::current_with_span(span))
					.await?;
			} else {
				let stream = resp_recv.await?;
			}
		}

		let resp_enc = RespEnc::decode(stream).await?;
		debug!("client: got response to request {} (path {})", id, path);
		Resp::from_enc(resp_enc)
	}
}

impl SendLoop for ClientConn {}

#[async_trait]
impl RecvLoop for ClientConn {
	fn recv_handler(self: &Arc<Self>, id: RequestID, stream: ByteStream) {
		trace!("ClientConn recv_handler {}", id);

		let mut inflight = self.inflight.lock().unwrap();
		if let Some(ch) = inflight.remove(&id) {
			if ch.send(stream).is_err() {
				debug!("Could not send request response, probably because request was interrupted. Dropping response.");
			}
		}
	}
}