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//! An rpc server that process the message sent by client.
//!
//! An rpc server provides some service and wait for the client's requests.
//! The client connect rpc server first and then send requets to the server.
//!
//! You can try this example by running:
//!
//! cargo run --example rpc
use async_rdma::{LocalMr, LocalMrReadAccess, LocalMrWriteAccess, Rdma, RdmaBuilder};
use std::{alloc::Layout, sync::Arc, time::Duration};
use tokio::net::ToSocketAddrs;
#[derive(Clone, Debug)]
enum Request {
Echo { msg: String },
Sync,
}
#[derive(Clone, Debug)]
enum Response {
Echo { msg: String },
Sync,
}
/// Rpc server
struct Server {}
impl Server {
#[tokio::main]
async fn start<A: ToSocketAddrs>(addr: A) {
// wait for client to connect
let rdma = Arc::new(RdmaBuilder::default().listen(addr).await.unwrap());
// run rpc task loop
let sr_handler = tokio::spawn(Self::sr_task(rdma.clone()));
let wr_handler = tokio::spawn(Self::wr_task(rdma));
sr_handler.await.unwrap();
wr_handler.await.unwrap();
}
/// Server can't aware of rdma `read` or `write`, so we need sync with client
/// before client `read` and after `write`.
async fn sync_with_client(rdma: &Rdma) {
let mut lmr_sync = rdma
.alloc_local_mr(Layout::new::<Request>())
.map_err(|err| println!("{}", &err))
.unwrap();
//write data to lmr
unsafe { *(*lmr_sync.as_mut_ptr() as *mut Request) = Request::Sync };
rdma.send(&lmr_sync)
.await
.map_err(|err| println!("{}", &err))
.unwrap();
}
/// Loop used to process rpc requests powered by rdma 'read' and 'write'
async fn wr_task(rdma: Arc<Rdma>) {
loop {
// receive a lmr which was requested by client to `write` `Requests`
let lmr_req = rdma
.receive_local_mr()
.await
.map_err(|err| println!("{}", &err))
.unwrap();
Self::sync_with_client(&rdma).await;
let resp = unsafe {
// get 'Request' from lmr
let req = &*(*lmr_req.as_ptr() as *const Request);
Self::process_request(req)
};
// alloc a lmr for client to 'read' 'Response'
let mut lmr_resp = rdma
.alloc_local_mr(Layout::new::<Response>())
.map_err(|err| println!("{}", &err))
.unwrap();
// put 'Response' into lmr
unsafe { *(*lmr_resp.as_mut_ptr() as *mut Response) = resp };
Self::sync_with_client(&rdma).await;
// send the metadata of lmr to client to 'read'
rdma.send_local_mr(lmr_resp)
.await
.map_err(|err| println!("{}", &err))
.unwrap();
}
}
/// Loop used to process rpc requests powered by rdma 'send' and 'receive'
async fn sr_task(rdma: Arc<Rdma>) {
loop {
// wait for the `send` request sent by client
let resp = rdma
.receive()
.await
.map(|lmr_req| unsafe {
//get `Request` from mr
let req = &*(*lmr_req.as_ptr() as *const Request);
Self::process_request(req)
})
.map_err(|err| println!("{}", &err))
.unwrap();
let mut lmr_resp = rdma
.alloc_local_mr(Layout::new::<Response>())
.map_err(|err| println!("{}", &err))
.unwrap();
// put `Response` into a new mr and send it to client
unsafe { *(*lmr_resp.as_mut_ptr() as *mut Response) = resp };
rdma.send(&lmr_resp)
.await
.map_err(|err| println!("{}", &err))
.unwrap();
}
}
/// Process `Echo` rpc
fn echo(msg: String) -> Response {
Response::Echo { msg }
}
/// Process request and return the response
fn process_request(req: &Request) -> Response {
match req {
Request::Echo { msg } => Self::echo(msg.to_string()),
Request::Sync => Response::Sync,
}
}
}
fn transmute_lmr_to_string(lmr: &LocalMr) -> String {
unsafe {
let resp = &*(*lmr.as_ptr() as *const Response);
match resp {
Response::Echo { msg } => msg.to_string(),
_ => panic!("invalid input : {:?}", resp),
}
}
}
struct Client {
// stub of rdma information related to the server
rdma_stub: Rdma,
}
impl Client {
async fn new<A: ToSocketAddrs>(addr: A) -> Self {
// connect to server
// gid_index: 0:ipv6 1:ipv4(default)
let rdma_stub = RdmaBuilder::default()
.connect(addr)
.await
.map_err(|err| println!("{}", &err))
.unwrap();
Client { rdma_stub }
}
/// Echo rpc request method powered by rdma 'send' and 'receive'
///
/// Send 'msg' to rpc server and then receive the same content from server.
///
/// Show the usage of rdma 'send' and 'receive'
async fn echo_req_sr(&self, msg: String) -> String {
// allocate a local memory region according to the `layout`
let mut lmr_req = self
.rdma_stub
.alloc_local_mr(Layout::new::<Request>())
.map_err(|err| println!("{}", &err))
.unwrap();
//write data to lmr
unsafe { *(*lmr_req.as_mut_ptr() as *mut Request) = Request::Echo { msg } };
// send request to server by rdma `send`
self.rdma_stub
.send(&lmr_req)
.await
.map_err(|err| println!("{}", &err))
.unwrap();
// receive response from server by rdma `receive`
self.rdma_stub
.receive()
.await
.map(|lmr_resp| transmute_lmr_to_string(&lmr_resp))
.map_err(|err| println!("{}", &err))
.unwrap()
}
/// Echo rpc request method powered by rdma 'read' and 'write'
///
/// Send 'msg' to rpc server and then receive the same content from server.
///
/// Show the usage of rdma 'read' and 'write'
///
/// Server can't aware of rdma `read` or `write`, so we need sync with server
/// Before `read` and after `write`.
async fn echo_req_wr(&self, msg: String) -> String {
// allocate a local memory region according to the `layout`
let mut lmr_req = self
.rdma_stub
.alloc_local_mr(Layout::new::<Request>())
.map_err(|err| println!("{}", &err))
.unwrap();
// put data into lmr
unsafe { *(*lmr_req.as_mut_ptr() as *mut Request) = Request::Echo { msg } };
// request a remote mr located in the server
let mut rmr_req = self
.rdma_stub
.request_remote_mr(Layout::new::<Request>())
.await
.map_err(|err| println!("{}", &err))
.unwrap();
// write data from local mr to remote mr by rdma `write`
self.rdma_stub
.write(&lmr_req, &mut rmr_req)
.await
.map_err(|err| println!("{}", &err))
.unwrap();
// send metadata of the remote mr to make server aware of it.
self.rdma_stub
.send_remote_mr(rmr_req)
.await
.map_err(|err| println!("{}", &err))
.unwrap();
self.sync_with_server().await;
// wait for the server `send_mr`
let rmr_resp = self
.rdma_stub
.receive_remote_mr()
.await
.map_err(|err| println!("{}", &err))
.unwrap();
// received `Redponse` which was stored in remote mr
let mut lmr_resp = self
.rdma_stub
.alloc_local_mr(Layout::new::<Response>())
.map_err(|err| println!("{}", &err))
.unwrap();
self.sync_with_server().await;
// read `Response` from remote mr by rdma `read`
self.rdma_stub
.read(&mut lmr_resp, &rmr_resp)
.await
// convert memory region to 'String' or anything else you need in other scenarios.
.map_err(|err| println!("{}", &err))
.unwrap();
transmute_lmr_to_string(&lmr_resp)
}
/// Server can't aware of rdma `read` or `write`, so we need sync with server
/// before `read` and after `write`.
async fn sync_with_server(&self) {
// receive response from server by rdma 'receive'
self.rdma_stub
.receive()
.await
.map(|lmr_resp| unsafe {
let resp = &*(*lmr_resp.as_ptr() as *const Response);
if let Response::Sync = resp {
} else {
panic!("invalid response");
}
})
.map_err(|err| println!("{}", &err))
.unwrap()
}
}
#[tokio::main]
async fn main() {
tracing_subscriber::fmt::init();
//run rpc server
std::thread::spawn(|| Server::start("localhost:5555"));
println!("rpc server started");
//sleep for a second to wait for the server to start
tokio::time::sleep(Duration::new(1, 0)).await;
let msg_hello = String::from("hello");
let msg_world = String::from("world");
let client = Client::new("localhost:5555").await;
println!("request: {}", msg_hello);
let res = client.echo_req_sr(msg_hello).await;
println!("response: {}", res);
println!("request: {}", msg_world);
let res = client.echo_req_wr(msg_world).await;
println!("response: {}", res);
}