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go/internal/jsonrpc2/serve.go
Ian Cottrell 6dc6d5718f internal/jsonrpc2: change handler to a function type
Handler is now a function type that mapps to what used to be the Deliver method.
The only handler that used other methods was Canceller, for now that still
exists as LegacyHooks. Once the handlers are fully cleaned up we should be able
to re-implement canceller as handler middleware.
Each connection is now only allowed one handler, and it is passed to the Run
method, but handlers are composable.

Change-Id: I370e0459df851bb9c9c2a679b99cff073b94489e
Reviewed-on: https://go-review.googlesource.com/c/tools/+/226479
Run-TryBot: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
2020-04-06 13:48:45 +00:00

111 lines
3.0 KiB
Go

// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package jsonrpc2
import (
"context"
"fmt"
"log"
"net"
"os"
"time"
)
// NOTE: This file provides an experimental API for serving multiple remote
// jsonrpc2 clients over the network. For now, it is intentionally similar to
// net/http, but that may change in the future as we figure out the correct
// semantics.
// A StreamServer is used to serve incoming jsonrpc2 clients communicating over
// a newly created stream.
type StreamServer interface {
ServeStream(context.Context, Stream) error
}
// The ServerFunc type is an adapter that implements the StreamServer interface
// using an ordinary function.
type ServerFunc func(context.Context, Stream) error
// ServeStream calls f(ctx, s).
func (f ServerFunc) ServeStream(ctx context.Context, s Stream) error {
return f(ctx, s)
}
// HandlerServer returns a StreamServer that handles incoming streams using the
// provided handler.
func HandlerServer(h Handler) StreamServer {
return ServerFunc(func(ctx context.Context, s Stream) error {
conn := NewConn(s)
return conn.Run(ctx, h)
})
}
// ListenAndServe starts an jsonrpc2 server on the given address. If
// idleTimeout is non-zero, ListenAndServe exits after there are no clients for
// this duration, otherwise it exits only on error.
func ListenAndServe(ctx context.Context, network, addr string, server StreamServer, idleTimeout time.Duration) error {
ln, err := net.Listen(network, addr)
if err != nil {
return err
}
defer ln.Close()
if network == "unix" {
defer os.Remove(addr)
}
return Serve(ctx, ln, server, idleTimeout)
}
// Serve accepts incoming connections from the network, and handles them using
// the provided server. If idleTimeout is non-zero, ListenAndServe exits after
// there are no clients for this duration, otherwise it exits only on error.
func Serve(ctx context.Context, ln net.Listener, server StreamServer, idleTimeout time.Duration) error {
// Max duration: ~290 years; surely that's long enough.
const forever = 1<<63 - 1
if idleTimeout <= 0 {
idleTimeout = forever
}
connTimer := time.NewTimer(idleTimeout)
newConns := make(chan net.Conn)
doneListening := make(chan error)
closedConns := make(chan error)
go func() {
for {
nc, err := ln.Accept()
if err != nil {
doneListening <- fmt.Errorf("Accept(): %v", err)
return
}
newConns <- nc
}
}()
activeConns := 0
for {
select {
case netConn := <-newConns:
activeConns++
connTimer.Stop()
stream := NewHeaderStream(netConn, netConn)
go func() {
closedConns <- server.ServeStream(ctx, stream)
}()
case err := <-doneListening:
return err
case err := <-closedConns:
log.Printf("closed a connection with error: %v", err)
activeConns--
if activeConns == 0 {
connTimer.Reset(idleTimeout)
}
case <-connTimer.C:
return ErrIdleTimeout
case <-ctx.Done():
return ctx.Err()
}
}
}