1 files changed, 170 insertions, 108 deletions

diff --git a/src/rpc/rpc_helper.rs b/src/rpc/rpc_helper.rs
index ce291068..12d073b6 100644
--- a/src/rpc/rpc_helper.rs
+++ b/src/rpc/rpc_helper.rs
@@ -1,4 +1,5 @@
 //! Contain structs related to making RPCs
+use std::collections::HashMap;
 use std::sync::{Arc, RwLock};
 use std::time::Duration;
 
@@ -35,11 +36,11 @@ const DEFAULT_TIMEOUT: Duration = Duration::from_secs(300);
 #[derive(Copy, Clone)]
 pub struct RequestStrategy {
 	/// Min number of response to consider the request successful
-	pub rs_quorum: Option<usize>,
-	/// Should requests be dropped after enough response are received
-	pub rs_interrupt_after_quorum: bool,
+	rs_quorum: Option<usize>,
+	/// Send all requests at once
+	rs_send_all_at_once: Option<bool>,
 	/// Request priority
-	pub rs_priority: RequestPriority,
+	rs_priority: RequestPriority,
 	/// Custom timeout for this request
 	rs_timeout: Timeout,
 }
@@ -56,7 +57,7 @@ impl RequestStrategy {
 	pub fn with_priority(prio: RequestPriority) -> Self {
 		RequestStrategy {
 			rs_quorum: None,
-			rs_interrupt_after_quorum: false,
+			rs_send_all_at_once: None,
 			rs_priority: prio,
 			rs_timeout: Timeout::Default,
 		}
@@ -66,10 +67,9 @@ impl RequestStrategy {
 		self.rs_quorum = Some(quorum);
 		self
 	}
-	/// Set if requests can be dropped after quorum has been reached
-	/// In general true for read requests, and false for write
-	pub fn interrupt_after_quorum(mut self, interrupt: bool) -> Self {
-		self.rs_interrupt_after_quorum = interrupt;
+	/// Set quorum to be reached for request
+	pub fn send_all_at_once(mut self, value: bool) -> Self {
+		self.rs_send_all_at_once = Some(value);
 		self
 	}
 	/// Deactivate timeout for this request
@@ -235,31 +235,19 @@ impl RpcHelper {
 		let quorum = strategy.rs_quorum.unwrap_or(to.len());
 
 		let tracer = opentelemetry::global::tracer("garage");
-		let span_name = if strategy.rs_interrupt_after_quorum {
-			format!("RPC {} to {} of {}", endpoint.path(), quorum, to.len())
-		} else {
-			format!(
-				"RPC {} to {} (quorum {})",
-				endpoint.path(),
-				to.len(),
-				quorum
-			)
-		};
+		let span_name = format!("Read RPC {} to {} of {}", endpoint.path(), quorum, to.len());
+
 		let mut span = tracer.start(span_name);
 		span.set_attribute(KeyValue::new("from", format!("{:?}", self.0.our_node_id)));
 		span.set_attribute(KeyValue::new("to", format!("{:?}", to)));
 		span.set_attribute(KeyValue::new("quorum", quorum as i64));
-		span.set_attribute(KeyValue::new(
-			"interrupt_after_quorum",
-			strategy.rs_interrupt_after_quorum.to_string(),
-		));
 
-		self.try_call_many_internal(endpoint, to, msg, strategy, quorum)
+		self.try_call_many_inner(endpoint, to, msg, strategy, quorum)
 			.with_context(Context::current_with_span(span))
 			.await
 	}
 
-	async fn try_call_many_internal<M, N, H, S>(
+	async fn try_call_many_inner<M, N, H, S>(
 		&self,
 		endpoint: &Arc<Endpoint<M, H>>,
 		to: &[Uuid],
@@ -273,12 +261,20 @@ impl RpcHelper {
 		H: StreamingEndpointHandler<M> + 'static,
 		S: Send + 'static,
 	{
-		let msg = msg.into_req().map_err(netapp::error::Error::from)?;
+		// Once quorum is reached, other requests don't matter.
+		// What we do here is only send the required number of requests
+		// to reach a quorum, priorizing nodes with the lowest latency.
+		// When there are errors, we start new requests to compensate.
+
+		// Reorder requests to priorize closeness / low latency
+		let request_order = self.request_order(to);
+		let send_all_at_once = strategy.rs_send_all_at_once.unwrap_or(false);
 
 		// Build future for each request
 		// They are not started now: they are added below in a FuturesUnordered
 		// object that will take care of polling them (see below)
-		let requests = to.iter().cloned().map(|to| {
+		let msg = msg.into_req().map_err(netapp::error::Error::from)?;
+		let mut requests = request_order.into_iter().map(|to| {
 			let self2 = self.clone();
 			let msg = msg.clone();
 			let endpoint2 = endpoint.clone();
@@ -291,93 +287,40 @@ impl RpcHelper {
 		let mut successes = vec![];
 		let mut errors = vec![];
 
-		if strategy.rs_interrupt_after_quorum {
-			// Case 1: once quorum is reached, other requests don't matter.
-			// What we do here is only send the required number of requests
-			// to reach a quorum, priorizing nodes with the lowest latency.
-			// When there are errors, we start new requests to compensate.
-
-			// Reorder requests to priorize closeness / low latency
-			let request_order = self.request_order(to);
-			let mut ord_requests = vec![(); request_order.len()]
-				.into_iter()
-				.map(|_| None)
-				.collect::<Vec<_>>();
-			for (to, fut) in requests {
-				let i = request_order.iter().position(|x| *x == to).unwrap();
-				ord_requests[i] = Some((to, fut));
+		// resp_stream will contain all of the requests that are currently in flight.
+		// (for the moment none, they will be added in the loop below)
+		let mut resp_stream = FuturesUnordered::new();
+
+		// Do some requests and collect results
+		while successes.len() < quorum {
+			// If the current set of requests that are running is not enough to possibly
+			// reach quorum, start some new requests.
+			while send_all_at_once || successes.len() + resp_stream.len() < quorum {
+				if let Some((req_to, fut)) = requests.next() {
+					let tracer = opentelemetry::global::tracer("garage");
+					let span = tracer.start(format!("RPC to {:?}", req_to));
+					resp_stream.push(tokio::spawn(
+						fut.with_context(Context::current_with_span(span)),
+					));
+				} else {
+					break;
+				}
 			}
 
-			// Make an iterator to take requests in their sorted order
-			let mut requests = ord_requests.into_iter().map(Option::unwrap);
-
-			// resp_stream will contain all of the requests that are currently in flight.
-			// (for the moment none, they will be added in the loop below)
-			let mut resp_stream = FuturesUnordered::new();
-
-			// Do some requests and collect results
-			'request_loop: while successes.len() < quorum {
-				// If the current set of requests that are running is not enough to possibly
-				// reach quorum, start some new requests.
-				while successes.len() + resp_stream.len() < quorum {
-					if let Some((req_to, fut)) = requests.next() {
-						let tracer = opentelemetry::global::tracer("garage");
-						let span = tracer.start(format!("RPC to {:?}", req_to));
-						resp_stream.push(tokio::spawn(
-							fut.with_context(Context::current_with_span(span)),
-						));
-					} else {
-						// If we have no request to add, we know that we won't ever
-						// reach quorum: bail out now.
-						break 'request_loop;
-					}
-				}
-				assert!(!resp_stream.is_empty()); // because of loop invariants
+			if successes.len() + resp_stream.len() < quorum {
+				// We know we won't ever reach quorum
+				break;
+			}
 
-				// Wait for one request to terminate
-				match resp_stream.next().await.unwrap().unwrap() {
-					Ok(msg) => {
-						successes.push(msg);
-					}
-					Err(e) => {
-						errors.push(e);
-					}
+			// Wait for one request to terminate
+			match resp_stream.next().await.unwrap().unwrap() {
+				Ok(msg) => {
+					successes.push(msg);
 				}
-			}
-		} else {
-			// Case 2: all of the requests need to be sent in all cases,
-			// and need to terminate. (this is the case for writes that
-			// must be spread to n nodes)
-			// Just start all the requests in parallel and return as soon
-			// as the quorum is reached.
-			let mut resp_stream = requests
-				.map(|(_, fut)| fut)
-				.collect::<FuturesUnordered<_>>();
-
-			while let Some(resp) = resp_stream.next().await {
-				match resp {
-					Ok(msg) => {
-						successes.push(msg);
-						if successes.len() >= quorum {
-							break;
-						}
-					}
-					Err(e) => {
-						errors.push(e);
-					}
+				Err(e) => {
+					errors.push(e);
 				}
 			}
-
-			if !resp_stream.is_empty() {
-				// Continue remaining requests in background.
-				// Note: these requests can get interrupted on process shutdown,
-				// we must not count on them being executed for certain.
-				// For all background things that have to happen with certainty,
-				// they have to be put in a proper queue that is persisted to disk.
-				tokio::spawn(async move {
-					resp_stream.collect::<Vec<Result<_, _>>>().await;
-				});
-			}
 		}
 
 		if successes.len() >= quorum {
@@ -432,4 +375,123 @@ impl RpcHelper {
 			.map(|(_, _, _, to)| to)
 			.collect::<Vec<_>>()
 	}
+
+	pub async fn try_write_many_sets<M, N, H, S>(
+		&self,
+		endpoint: &Arc<Endpoint<M, H>>,
+		to_sets: &[Vec<Uuid>],
+		msg: N,
+		strategy: RequestStrategy,
+	) -> Result<Vec<S>, Error>
+	where
+		M: Rpc<Response = Result<S, Error>> + 'static,
+		N: IntoReq<M>,
+		H: StreamingEndpointHandler<M> + 'static,
+		S: Send + 'static,
+	{
+		let quorum = strategy
+			.rs_quorum
+			.expect("internal error: missing quroum in try_write_many_sets");
+
+		let tracer = opentelemetry::global::tracer("garage");
+		let span_name = format!(
+			"Write RPC {} (quorum {} in {} sets)",
+			endpoint.path(),
+			quorum,
+			to_sets.len()
+		);
+
+		let mut span = tracer.start(span_name);
+		span.set_attribute(KeyValue::new("from", format!("{:?}", self.0.our_node_id)));
+		span.set_attribute(KeyValue::new("to", format!("{:?}", to_sets)));
+		span.set_attribute(KeyValue::new("quorum", quorum as i64));
+
+		self.try_write_many_sets_inner(endpoint, to_sets, msg, strategy, quorum)
+			.with_context(Context::current_with_span(span))
+			.await
+	}
+
+	async fn try_write_many_sets_inner<M, N, H, S>(
+		&self,
+		endpoint: &Arc<Endpoint<M, H>>,
+		to_sets: &[Vec<Uuid>],
+		msg: N,
+		strategy: RequestStrategy,
+		quorum: usize,
+	) -> Result<Vec<S>, Error>
+	where
+		M: Rpc<Response = Result<S, Error>> + 'static,
+		N: IntoReq<M>,
+		H: StreamingEndpointHandler<M> + 'static,
+		S: Send + 'static,
+	{
+		let msg = msg.into_req().map_err(netapp::error::Error::from)?;
+
+		let mut peers = HashMap::<Uuid, Vec<usize>>::new();
+		for (i, set) in to_sets.iter().enumerate() {
+			for peer in set.iter() {
+				peers.entry(*peer).or_default().push(i);
+			}
+		}
+
+		let requests = peers.iter().map(|(peer, _)| {
+			let self2 = self.clone();
+			let msg = msg.clone();
+			let endpoint2 = endpoint.clone();
+			let to = *peer;
+			let tracer = opentelemetry::global::tracer("garage");
+			let span = tracer.start(format!("RPC to {:?}", to));
+			let fut = async move { (to, self2.call(&endpoint2, to, msg, strategy).await) };
+			tokio::spawn(fut.with_context(Context::current_with_span(span)))
+		});
+		let mut resp_stream = requests.collect::<FuturesUnordered<_>>();
+
+		let mut successes = vec![];
+		let mut errors = vec![];
+
+		let mut set_counters = vec![(0, 0); to_sets.len()];
+
+		while !resp_stream.is_empty() {
+			let (node, resp) = resp_stream.next().await.unwrap().unwrap();
+
+			match resp {
+				Ok(msg) => {
+					for set in peers.get(&node).unwrap().iter() {
+						set_counters[*set].0 += 1;
+					}
+					successes.push(msg);
+				}
+				Err(e) => {
+					for set in peers.get(&node).unwrap().iter() {
+						set_counters[*set].1 += 1;
+					}
+					errors.push(e);
+				}
+			}
+
+			if set_counters.iter().all(|x| x.0 > quorum) {
+				// Success
+
+				// Continue all other requets in background
+				tokio::spawn(async move {
+					resp_stream.collect::<Vec<Result<_, _>>>().await;
+				});
+
+				return Ok(successes);
+			}
+
+			if set_counters
+				.iter()
+				.enumerate()
+				.any(|(i, x)| x.1 + quorum > to_sets[i].len())
+			{
+				// Too many errors in this set, we know we won't get a quorum
+				break;
+			}
+		}
+
+		// Failure, could not get quorum
+		let errors = errors.iter().map(|e| format!("{}", e)).collect::<Vec<_>>();
+		Err(Error::Quorum(quorum, successes.len(), peers.len(), errors))
+	}
 }