Documentation
¶
Overview ¶
Package rpc implements the Cap'n Proto RPC protocol.
Example ¶
package main
import (
"fmt"
"net"
"golang.org/x/net/context"
"zombiezen.com/go/capnproto2/rpc"
"zombiezen.com/go/capnproto2/rpc/internal/testcapnp"
"zombiezen.com/go/capnproto2/server"
)
func main() {
// Create an in-memory transport. In a real application, you would probably
// use a net.TCPConn (for RPC) or an os.Pipe (for IPC).
p1, p2 := net.Pipe()
t1, t2 := rpc.StreamTransport(p1), rpc.StreamTransport(p2)
// Server-side
srv := testcapnp.Adder_ServerToClient(AdderServer{})
serverConn := rpc.NewConn(t1, rpc.MainInterface(srv.Client))
defer serverConn.Wait()
// Client-side
ctx := context.Background()
clientConn := rpc.NewConn(t2)
defer clientConn.Close()
adderClient := testcapnp.Adder{Client: clientConn.Bootstrap(ctx)}
// Every client call returns a promise. You can make multiple calls
// concurrently.
call1 := adderClient.Add(ctx, func(p testcapnp.Adder_add_Params) error {
p.SetA(5)
p.SetB(2)
return nil
})
call2 := adderClient.Add(ctx, func(p testcapnp.Adder_add_Params) error {
p.SetA(10)
p.SetB(20)
return nil
})
// Calling Struct() on a promise waits until it returns.
result1, err := call1.Struct()
if err != nil {
fmt.Println("Add #1 failed:", err)
return
}
result2, err := call2.Struct()
if err != nil {
fmt.Println("Add #2 failed:", err)
return
}
fmt.Println("Results:", result1.Result(), result2.Result())
}
// An AdderServer is a local implementation of the Adder interface.
type AdderServer struct{}
// Add implements a method
func (AdderServer) Add(call testcapnp.Adder_add) error {
// Acknowledging the call allows other calls to be made (it returns the Answer
// to the caller).
server.Ack(call.Options)
// Parameters are accessed with call.Params.
a := call.Params.A()
b := call.Params.B()
// A result struct is allocated for you at call.Results.
call.Results.SetResult(a + b)
return nil
}
Output: Results: 7 30
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
var (
ErrConnClosed = errors.New("rpc: connection closed")
)
Errors
Functions ¶
This section is empty.
Types ¶
type Conn ¶
type Conn struct {
// contains filtered or unexported fields
}
A Conn is a connection to another Cap'n Proto vat. It is safe to use from multiple goroutines.
func NewConn ¶
func NewConn(t Transport, options ...ConnOption) *Conn
NewConn creates a new connection that communicates on c. Closing the connection will cause c to be closed.
type ConnOption ¶
type ConnOption struct {
// contains filtered or unexported fields
}
A ConnOption is an option for opening a connection.
func MainInterface ¶
func MainInterface(client capnp.Client) ConnOption
MainInterface specifies that the connection should use client when receiving bootstrap messages. By default, all bootstrap messages will fail.
func SendBufferSize ¶
func SendBufferSize(numMsgs int) ConnOption
SendBufferSize sets the number of outgoing messages to buffer on the connection. This is in addition to whatever buffering the connection's transport performs.
type Transport ¶
type Transport interface {
// SendMessage sends msg.
SendMessage(ctx context.Context, msg rpccapnp.Message) error
// RecvMessage waits to receive a message and returns it.
// Implementations may re-use buffers between calls, so the message is
// only valid until the next call to RecvMessage.
RecvMessage(ctx context.Context) (rpccapnp.Message, error)
// Close releases any resources associated with the transport.
Close() error
}
Transport is the interface that abstracts sending and receiving individual messages of the Cap'n Proto RPC protocol.
func StreamTransport ¶
func StreamTransport(rwc io.ReadWriteCloser) Transport
StreamTransport creates a transport that sends and receives messages by serializing and deserializing unpacked Cap'n Proto messages. Closing the transport will close the underlying ReadWriteCloser.
Source Files
¶
Directories
¶
| Path | Synopsis |
|---|---|
|
internal
|
|
|
logtransport
Package logtransport provides a transport that logs all of its messages.
|
Package logtransport provides a transport that logs all of its messages. |
|
logutil
Package logutil provides functions that can print to a logger.
|
Package logutil provides functions that can print to a logger. |
|
pipetransport
Package pipetransport provides in-memory implementations of rpc.Transport for testing.
|
Package pipetransport provides in-memory implementations of rpc.Transport for testing. |
|
refcount
Package refcount implements a reference-counting client.
|
Package refcount implements a reference-counting client. |