README
¶
console
Golang package for dealing with consoles. Light on deps and a simple API.
Modifying the current process
current := console.Current()
defer current.Reset()
if err := current.SetRaw(); err != nil {
}
ws, err := current.Size()
current.Resize(ws)
Project details
console is a containerd sub-project, licensed under the Apache 2.0 license. As a containerd sub-project, you will find the:
information in our containerd/project repository.
Documentation
¶
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ErrNotAConsole = errors.New("provided file is not a console")
Functions ¶
func ClearONLCR ¶
ClearONLCR sets the necessary tty_ioctl(4)s to ensure that a pty pair created by us acts normally. In particular, a not-very-well-known default of Linux unix98 ptys is that they have +onlcr by default. While this isn't a problem for terminal emulators, because we relay data from the terminal we also relay that funky line discipline.
Types ¶
type Console ¶
type Console interface {
File
// Resize resizes the console to the provided window size
Resize(WinSize) error
// ResizeFrom resizes the calling console to the size of the
// provided console
ResizeFrom(Console) error
// SetRaw sets the console in raw mode
SetRaw() error
// DisableEcho disables echo on the console
DisableEcho() error
// Reset restores the console to its orignal state
Reset() error
// Size returns the window size of the console
Size() (WinSize, error)
}
func ConsoleFromFile ¶
ConsoleFromFile returns a console using the provided file nolint:golint
type EpollConsole ¶
type EpollConsole struct {
Console
// contains filtered or unexported fields
}
EpollConsole acts like a console but registers its file descriptor with an epoll fd and uses epoll API to perform I/O.
func (*EpollConsole) Read ¶
func (ec *EpollConsole) Read(p []byte) (n int, err error)
Read reads up to len(p) bytes into p. It returns the number of bytes read (0 <= n <= len(p)) and any error encountered.
If the console's read returns EAGAIN or EIO, we assume that it's a temporary error because the other side went away and wait for the signal generated by epoll event to continue.
func (*EpollConsole) Shutdown ¶
func (ec *EpollConsole) Shutdown(close func(int) error) error
Shutdown closes the file descriptor and signals call waiters for this fd. It accepts a callback which will be called with the console's fd. The callback typically will be used to do further cleanup such as unregister the console's fd from the epoll interface. User should call Shutdown and wait for all I/O operation to be finished before closing the console.
func (*EpollConsole) Write ¶
func (ec *EpollConsole) Write(p []byte) (n int, err error)
Writes len(p) bytes from p to the console. It returns the number of bytes written from p (0 <= n <= len(p)) and any error encountered that caused the write to stop early.
If writes to the console returns EAGAIN or EIO, we assume that it's a temporary error because the other side went away and wait for the signal generated by epoll event to continue.
type Epoller ¶
type Epoller struct {
// contains filtered or unexported fields
}
Epoller manages multiple epoll consoles using edge-triggered epoll api so we dont have to deal with repeated wake-up of EPOLLER or EPOLLHUP. For more details, see: - https://github.com/systemd/systemd/pull/4262 - https://github.com/moby/moby/issues/27202
Example usage of Epoller and EpollConsole can be as follow:
epoller, _ := NewEpoller()
epollConsole, _ := epoller.Add(console)
go epoller.Wait()
var (
b bytes.Buffer
wg sync.WaitGroup
)
wg.Add(1)
go func() {
io.Copy(&b, epollConsole)
wg.Done()
}()
// perform I/O on the console
epollConsole.Shutdown(epoller.CloseConsole)
wg.Wait()
epollConsole.Close()
func NewEpoller ¶
NewEpoller returns an instance of epoller with a valid epoll fd.
func (*Epoller) Add ¶
func (e *Epoller) Add(console Console) (*EpollConsole, error)
Add creates an epoll console based on the provided console. The console will be registered with EPOLLET (i.e. using edge-triggered notification) and its file descriptor will be set to non-blocking mode. After this, user should use the return console to perform I/O.
func (*Epoller) CloseConsole ¶
CloseConsole unregisters the console's file descriptor from epoll interface
Source Files