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
|
//! Contain structs related to making RPCs
use std::sync::Arc;
use std::time::Duration;
use futures::future::join_all;
use futures::stream::futures_unordered::FuturesUnordered;
use futures::stream::StreamExt;
use futures_util::future::FutureExt;
use tokio::select;
pub use netapp::endpoint::{Endpoint, EndpointHandler, Message as Rpc};
use netapp::peering::fullmesh::FullMeshPeeringStrategy;
pub use netapp::proto::*;
pub use netapp::{NetApp, NodeID};
use garage_util::background::BackgroundRunner;
use garage_util::data::Uuid;
use garage_util::error::Error;
const DEFAULT_TIMEOUT: Duration = Duration::from_secs(10);
/// Strategy to apply when making RPC
#[derive(Copy, Clone)]
pub struct RequestStrategy {
/// Max time to wait for reponse
pub rs_timeout: Duration,
/// 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,
/// Request priority
pub rs_priority: RequestPriority,
}
impl RequestStrategy {
/// Create a RequestStrategy with default timeout and not interrupting when quorum reached
pub fn with_priority(prio: RequestPriority) -> Self {
RequestStrategy {
rs_timeout: DEFAULT_TIMEOUT,
rs_quorum: None,
rs_interrupt_after_quorum: false,
rs_priority: prio,
}
}
/// Set quorum to be reached for request
pub fn with_quorum(mut self, quorum: usize) -> Self {
self.rs_quorum = Some(quorum);
self
}
/// Set timeout of the strategy
pub fn with_timeout(mut self, timeout: Duration) -> Self {
self.rs_timeout = timeout;
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;
self
}
}
#[derive(Clone)]
pub struct RpcHelper {
pub(crate) fullmesh: Arc<FullMeshPeeringStrategy>,
pub(crate) background: Arc<BackgroundRunner>,
}
impl RpcHelper {
pub async fn call<M, H, S>(
&self,
endpoint: &Endpoint<M, H>,
to: Uuid,
msg: M,
strat: RequestStrategy,
) -> Result<S, Error>
where
M: Rpc<Response = Result<S, Error>>,
H: EndpointHandler<M>,
{
self.call_arc(endpoint, to, Arc::new(msg), strat).await
}
pub async fn call_arc<M, H, S>(
&self,
endpoint: &Endpoint<M, H>,
to: Uuid,
msg: Arc<M>,
strat: RequestStrategy,
) -> Result<S, Error>
where
M: Rpc<Response = Result<S, Error>>,
H: EndpointHandler<M>,
{
let node_id = to.into();
select! {
res = endpoint.call(&node_id, &msg, strat.rs_priority) => Ok(res??),
_ = tokio::time::sleep(strat.rs_timeout) => Err(Error::Timeout),
}
}
pub async fn call_many<M, H, S>(
&self,
endpoint: &Endpoint<M, H>,
to: &[Uuid],
msg: M,
strat: RequestStrategy,
) -> Vec<(Uuid, Result<S, Error>)>
where
M: Rpc<Response = Result<S, Error>>,
H: EndpointHandler<M>,
{
let msg = Arc::new(msg);
let resps = join_all(
to.iter()
.map(|to| self.call_arc(endpoint, *to, msg.clone(), strat)),
)
.await;
to.iter()
.cloned()
.zip(resps.into_iter())
.collect::<Vec<_>>()
}
pub async fn broadcast<M, H, S>(
&self,
endpoint: &Endpoint<M, H>,
msg: M,
strat: RequestStrategy,
) -> Vec<(Uuid, Result<S, Error>)>
where
M: Rpc<Response = Result<S, Error>>,
H: EndpointHandler<M>,
{
let to = self
.fullmesh
.get_peer_list()
.iter()
.map(|p| p.id.into())
.collect::<Vec<_>>();
self.call_many(endpoint, &to[..], msg, strat).await
}
/// Make a RPC call to multiple servers, returning either a Vec of responses, or an error if
/// strategy could not be respected due to too many errors
pub async fn try_call_many<M, H, S>(
&self,
endpoint: &Arc<Endpoint<M, H>>,
to: &[Uuid],
msg: M,
strategy: RequestStrategy,
) -> Result<Vec<S>, Error>
where
M: Rpc<Response = Result<S, Error>> + 'static,
H: EndpointHandler<M> + 'static,
S: Send,
{
let msg = Arc::new(msg);
let mut resp_stream = to
.to_vec()
.into_iter()
.map(|to| {
let self2 = self.clone();
let msg = msg.clone();
let endpoint2 = endpoint.clone();
async move { self2.call_arc(&endpoint2, to, msg, strategy).await }
})
.collect::<FuturesUnordered<_>>();
let mut results = vec![];
let mut errors = vec![];
let quorum = strategy.rs_quorum.unwrap_or(to.len());
while let Some(resp) = resp_stream.next().await {
match resp {
Ok(msg) => {
results.push(msg);
if results.len() >= quorum {
break;
}
}
Err(e) => {
errors.push(e);
}
}
}
if results.len() >= quorum {
// Continue requests in background.
// Continue the remaining requests immediately using tokio::spawn
// but enqueue a task in the background runner
// to ensure that the process won't exit until the requests are done
// (if we had just enqueued the resp_stream.collect directly in the background runner,
// the requests might have been put on hold in the background runner's queue,
// in which case they might timeout or otherwise fail)
if !strategy.rs_interrupt_after_quorum {
let wait_finished_fut = tokio::spawn(async move {
resp_stream.collect::<Vec<_>>().await;
});
self.background.spawn(wait_finished_fut.map(|_| Ok(())));
}
Ok(results)
} else {
let errors = errors.iter().map(|e| format!("{}", e)).collect::<Vec<_>>();
Err(Error::TooManyErrors(errors))
}
}
}
|
