ttrpc/handshake.go
Stephen J Day 256c17bccd
ttrpc: use os.Getuid/os.Getgid directly
Because of issues with glibc, using the `os/user` package can cause when
calling `user.Current()`. Neither the Go maintainers or glibc developers
could be bothered to fix it, so we have to work around it by calling the
uid and gid functions directly. This is probably better because we don't
actually use much of the data provided in the `user.User` struct.

This required some refactoring to have better control over when the uid
and gid are resolved. Rather than checking the current user on every
connection, we now resolve it once at initialization. To test that this
provided an improvement in performance, a benchmark was added.
Unfortunately, this exposed a regression in the performance of unix
sockets in Go when `(*UnixConn).File` is called. The underlying culprit
of this performance regression is still at large.

The following open issues describe the underlying problem in more
detail:

https://github.com/golang/go/issues/13470
https://sourceware.org/bugzilla/show_bug.cgi?id=19341

In better news, I now have an entire herd of shaved yaks.

Signed-off-by: Stephen J Day <stephen.day@docker.com>
2017-11-30 20:21:50 -08:00

35 lines
1.1 KiB
Go

package ttrpc
import (
"context"
"net"
)
// Handshaker defines the interface for connection handshakes performed on the
// server or client when first connecting.
type Handshaker interface {
// Handshake should confirm or decorate a connection that may be incoming
// to a server or outgoing from a client.
//
// If this returns without an error, the caller should use the connection
// in place of the original connection.
//
// The second return value can contain credential specific data, such as
// unix socket credentials or TLS information.
//
// While we currently only have implementations on the server-side, this
// interface should be sufficient to implement similar handshakes on the
// client-side.
Handshake(ctx context.Context, conn net.Conn) (net.Conn, interface{}, error)
}
type handshakerFunc func(ctx context.Context, conn net.Conn) (net.Conn, interface{}, error)
func (fn handshakerFunc) Handshake(ctx context.Context, conn net.Conn) (net.Conn, interface{}, error) {
return fn(ctx, conn)
}
func noopHandshake(ctx context.Context, conn net.Conn) (net.Conn, interface{}, error) {
return conn, nil, nil
}