[−][src]Crate toy_rpc
A toy RPC crate based on async-std
that mimics the golang
's net/rpc
package
This crate aims at providing an easy-to-use RPC that is similar to golang
's
net/rpc
.
The usage is similar to that of golang
's net/rpc
with functions sharing similar
names and functionalities. Certain function names are changed to be more rusty.
Because rust
doesn't have reflection, attribute macros are used to make certain
method "exported".
Content
Crate Feature Flags
This crate offers the following features flag
std
: enablesserde/std
serde_bincode
: the default codec will usebincode
for serialization/deserializationserde_json
: the default codec will useserde_json
forjson
serialization/deserializationserde_cbor
: the default codec will useserde_cbor
for serialization/deserializationserde_rmp
: the default codec will usermp-serde
for serialization/deserializationlogging
: enables loggingtide
: enablestide
integration on the server sideactix-web
: enablesactix-web
integration on the server sidesurf
: enables HTTP client on the client side
Default Features
[features]
default = [
"std",
"serde_bincode",
"tide",
"surf",
]
Documentation
The following documentation is adapted based on golang
's documentation.
This crate provides access to the methods marked with #[export_impl]
and #[export_method]
of an object across a network connection. A server
registers an object, making it visible as a service with a name provided by the user.
After the registration, the "exported" methods will be accessible remotely.
A server may register multiple objects as multiple services, and multiple
objects of the same type or different types could be registered on the same
Server
object.
To export a method, use #[export_method]
attribute in an impl block marked with
#[export_impl]
attribute. This crate currently only
support using #[export_impl]
attribute
on one
impl block per type.
struct ExampleService { } #[export_impl] impl ExampleService { #[export_method] async fn exported_method(&self, args: ()) -> Result<String, String> { Ok("This is an exported method".to_string()) } async fn not_exported_method(&self, args: ()) -> Result<String, String> { Ok("This method is NOT exported".to_string()) } }
The methods to export must meet the following criteria on the server side
-
the method resides in an impl block marked with
#[export_impl]
-
the method is marked with
#[export_method]
attribute -
the method takes one argument other than
&self
and returns aResult<T, E>
- the argument must implement trait
serde::Deserialize
- the
Ok
typeT
of the result must implement traitserde::Serialize
- the
Err
typeE
of the result must implement traitToString
- the argument must implement trait
-
the method is essentially in the form
struct ServiceState { } #[export_impl] impl ServiceState { #[export_method] async fn method_name(&self, args: Req) -> Result<Res, Msg> where Req: serde::Deserialize, Res: serde::Serialize, Msg: ToString, { unimplemented!() } }
Req
and Res
are marshaled/unmarshaled (serialized/deserialized) by serde
.
Realistically the Req
and Res
type must also be marshaled/unmarshaled on
the client side, and thus Req
and Res
must both implement both
serde::Serialize
and serde::Deserialize
.
The method's argument reprements the argument provided by the client caller,
and the Ok
type of result represents success parameters to be returned to
the client caller. The Err
type of result is passed back to the client as
a String
.
The server may handle requests on a single connection by calling serve_conn
,
and it may handle multiple connections by creating a async_std::net::TcpListener
and call accept
. Integration with HTTP currently only supports tide
by calling
into_endpoint
.
A client wishing to use the service establishes a async_std::net::TcpStream
connection
and then creates Client
over the connection. The convenience function dial
performs
this step for raw TCP socket connection, and dial_http
performs this for an HTTP
connection. A Client
with HTTP connection or socket connection has three methods, call
, async_call
,
and spawn_task
, to specify the service and method to call and the argument.
Please note that call_http
, async_call_http
and spawn_task_http
are becoming deprecated
as the same API now can be called for both a socket client and an HTTP client.
call
method is synchronous and waits for the remote call to complete and then returns the result.async_call
is theasync
versions ofcall
andcall_http
, respectively. Because they areasync
functions, they must be called with.await
to be executed.spawn_task
method spawns anasync
task and returns aJoinHandle
. The result can be obtained using theJoinHandle
.
Unless an explicity codec is set up (with serve_codec
method, HTTP is NOT supported yet),
the default codec specified by one of the following features tags (bincode
, serde_json
)
will be used to transport data.
Examples
A few simple examples are shown below. More examples can be found in the examples
directory in the repo.
RPC over socket
The default feature flags will work with the example below.
server.rs
use async_std::net::TcpListener; use async_std::sync::{Arc, Mutex}; use async_std::task; use serde::{Serialize, Deserialize}; use toy_rpc::macros::{export_impl, service}; use toy_rpc::Server; pub struct ExampleService { counter: Mutex<i32> } #[derive(Debug, Serialize, Deserialize)] pub struct ExampleRequest { pub a: u32, } #[derive(Debug, Serialize, Deserialize)] pub struct ExampleResponse { a: u32, } #[async_trait::async_trait] trait Rpc { async fn echo(&self, req: ExampleRequest) -> Result<ExampleResponse, String>; } #[async_trait::async_trait] #[export_impl] impl Rpc for ExampleService { #[export_method] async fn echo(&self, req: ExampleRequest) -> Result<ExampleResponse, String> { let mut counter = self.counter.lock().await; *counter += 1; let res = ExampleResponse{ a: req.a }; Ok(res) } } #[async_std::main] async fn main() { let addr = "127.0.0.1:8888"; let example_service = Arc::new( ExampleService { counter: Mutex::new(0), } ); let server = Server::builder() .register("example", service!(example_service, ExampleService)) .build(); let listener = TcpListener::bind(addr).await.unwrap(); println!("Starting listener at {}", &addr); let handle = task::spawn(async move { server.accept(listener).await.unwrap(); }); handle.await; }
client.rs
use serde::{Serialize, Deserialize}; use toy_rpc::Client; use toy_rpc::error::Error; #[derive(Debug, Serialize, Deserialize)] struct ExampleRequest { a: u32 } #[derive(Debug, Serialize, Deserialize)] struct ExampleResponse { a: u32 } #[async_std::main] async fn main() { let addr = "127.0.0.1:8888"; let client = Client::dial(addr).await.unwrap(); let args = ExampleRequest{a: 1}; let reply: Result<ExampleResponse, Error> = client.call("example.echo", &args); println!("{:?}", reply); }
RPC over HTTP with tide
The default feature flags will work with the example below.
server.rs
use async_std::sync::{Arc, Mutex}; use serde::{Serialize, Deserialize}; use toy_rpc::macros::{export_impl, service}; use toy_rpc::Server; pub struct ExampleService { counter: Mutex<i32> } #[derive(Debug, Serialize, Deserialize)] pub struct ExampleRequest { pub a: u32, } #[derive(Debug, Serialize, Deserialize)] pub struct ExampleResponse { a: u32, } #[async_trait::async_trait] trait Rpc { async fn echo(&self, req: ExampleRequest) -> Result<ExampleResponse, String>; } #[async_trait::async_trait] #[export_impl] impl Rpc for ExampleService { #[export_method] async fn echo(&self, req: ExampleRequest) -> Result<ExampleResponse, String> { let mut counter = self.counter.lock().await; *counter += 1; let res = ExampleResponse{ a: req.a }; Ok(res) } } #[async_std::main] async fn main() -> tide::Result<()> { let addr = "127.0.0.1:8888"; let example_service = Arc::new( ExampleService { counter: Mutex::new(0), } ); let server = Server::builder() .register("example", service!(example_service, ExampleService)) .build(); let mut app = tide::new(); app.at("/rpc/").nest(server.into_endpoint()); "handle_http" is a conenience function that calls "into_endpoint" // with the "tide" feature turned on and "actix-web" feature disabled //app.at("/rpc/").nest(server.handle_http()); app.listen(addr).await?; Ok(()) }
client.rs
use serde::{Serialize, Deserialize}; use toy_rpc::Client; use toy_rpc::error::Error; #[derive(Debug, Serialize, Deserialize)] struct ExampleRequest { a: u32 } #[derive(Debug, Serialize, Deserialize)] struct ExampleResponse { a: u32 } #[async_std::main] async fn main() { // note that the endpoint path must be specified let path = "http://127.0.0.1:8888/rpc/"; let client = Client::dial_http(path).await.unwrap(); let args = ExampleRequest{a: 1}; let reply: Result<ExampleResponse, Error> = client.call("example.echo", &args); println!("{:?}", reply); }
RPC over HTTP with actix-web
toy-rpc = { version = "0.4.2", default-features = false, features = ["std", "serde_bincode", "actix-web", "surf"] }
server.rs
use async_std::sync::{Arc, Mutex}; use serde::{Serialize, Deserialize}; use actix_web::{App, HttpServer, web}; use toy_rpc::macros::{export_impl, service}; use toy_rpc::Server; pub struct ExampleService { counter: Mutex<i32> } #[derive(Debug, Serialize, Deserialize)] pub struct ExampleRequest { pub a: u32, } #[derive(Debug, Serialize, Deserialize)] pub struct ExampleResponse { a: u32, } #[async_trait::async_trait] trait Rpc { async fn echo(&self, req: ExampleRequest) -> Result<ExampleResponse, String>; } #[async_trait::async_trait] #[export_impl] impl Rpc for ExampleService { #[export_method] async fn echo(&self, req: ExampleRequest) -> Result<ExampleResponse, String> { let mut counter = self.counter.lock().await; *counter += 1; let res = ExampleResponse{ a: req.a }; Ok(res) } } #[actix_web::main] async fn main() -> std::io::Result<()> { let addr = "127.0.0.1:8888"; let example_service = Arc::new( ExampleService { counter: Mutex::new(0), } ); let server = Server::builder() .register("example", service!(example_service, ExampleService)) .build(); HttpServer::new( move || { App::new() .service( web::scope("/rpc/") .app_data(app_data.clone()) .configure(Server::scope_config) // The line above may be replaced with line below if "actix-web" // is enabled and "tide" is disabled //.configure(Server::handle_http()) // use the convenience "handle_http" ) } ) .bind(addr)? .run() .await }
client.rs
use serde::{Serialize, Deserialize}; use toy_rpc::Client; use toy_rpc::error::Error; #[derive(Debug, Serialize, Deserialize)] struct ExampleRequest { a: u32 } #[derive(Debug, Serialize, Deserialize)] struct ExampleResponse { a: u32 } #[async_std::main] async fn main() { // note that the endpoint path must be specified let path = "http://127.0.0.1:8888/rpc/"; let client = Client::dial_http(path).await.unwrap(); let args = ExampleRequest{a: 1}; let reply: Result<ExampleResponse, Error> = client.call("example.echo", &args); println!("{:?}", reply); }
Change Log
0.4.4
- Modified traits
CodecRead
,CodecWrite
,ServerCodec
,ClientCodec
to no longer return number of bytes written - The number of bytes written for header and body will be logged separately
0.4.3
- Removed previously unused NoneError
- Unified
call
,async_call
andspawn_task
for socket client and HTTP client. Thecall_http
,async_call_http
, andspawn_task_http
methods are kept for compatibility.
0.4.2
- Temporary fix of
spawn_task()
andspawn_task_http()
withArc<Mutex<_>>
until lifetime with async task is figured out. As a result,Client
no longer needs to be declaredmut
.
0.4.1
- Updated documentation
0.4.0
- Added
actix-web
feature flag to support integration withactix-web
0.3.1
- Added
serde_rmp
features flag - Updated and corrected examples in the documentation
0.3.0
- Added
serde_cbor
feature flag - Changed
bincode
feature flag toserde_bincode
Future Plan
warp
integration- support other I/O connection
- unify
call
,async_call
, andspawn_task
for raw connection and HTTP connection
Re-exports
pub use client::Client; |
pub use server::Server; |
pub use server::ServerBuilder; |
pub use erased_serde; |
pub use lazy_static; |
Modules
client | |
codec | |
error | |
macros | |
message | |
server | |
service | |
transport |