dotcloud/docker

package grpc // import "github.com/docker/docker/api/server/router/grpc"

import (
    "context"
    "net/http"

    "github.com/pkg/errors"
    "golang.org/x/net/http2"
)

func (gr *grpcRouter) serveGRPC(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
    h, ok := w.(http.Hijacker)
    if !ok {
        return errors.New("handler does not support hijack")
    }
    proto := r.Header.Get("Upgrade")
    if proto == "" {
        return errors.New("no upgrade proto in request")
    }
    if proto != "h2c" {
        return errors.Errorf("protocol %s not supported", proto)
    }

    conn, _, err := h.Hijack()
    if err != nil {
        return err
    }
    resp := &http.Response{
        StatusCode: http.StatusSwitchingProtocols,
        ProtoMajor: 1,
        ProtoMinor: 1,
        Header:     http.Header{},
    }
    resp.Header.Set("Connection", "Upgrade")
    resp.Header.Set("Upgrade", proto)

    // set raw mode
    conn.Write([]byte{})
    resp.Write(conn)

    // https://godoc.org/golang.org/x/net/http2#Server.ServeConn
    // TODO: is it a problem that conn has already been written to?
    gr.h2Server.ServeConn(conn, &http2.ServeConnOpts{Handler: gr.grpcServer})
    return nil
}