syncthing/vendor/github.com/cheggaaa/pb/pb_win.go
Jakob Borg 916ec63af6 cmd/stdiscosrv: New discovery server (fixes #4618)
This is a new revision of the discovery server. Relevant changes and
non-changes:

- Protocol towards clients is unchanged.

- Recommended large scale design is still to be deployed nehind nginx (I
  tested, and it's still a lot faster at terminating TLS).

- Database backend is leveldb again, only. It scales enough, is easy to
  setup, and we don't need any backend to take care of.

- Server supports replication. This is a simple TCP channel - protect it
  with a firewall when deploying over the internet. (We deploy this within
  the same datacenter, and with firewall.) Any incoming client announces
  are sent over the replication channel(s) to other peer discosrvs.
  Incoming replication changes are applied to the database as if they came
  from clients, but without the TLS/certificate overhead.

- Metrics are exposed using the prometheus library, when enabled.

- The database values and replication protocol is protobuf, because JSON
  was quite CPU intensive when I tried that and benchmarked it.

- The "Retry-After" value for failed lookups gets slowly increased from
  a default of 120 seconds, by 5 seconds for each failed lookup,
  independently by each discosrv. This lowers the query load over time for
  clients that are never seen. The Retry-After maxes out at 3600 after a
  couple of weeks of this increase. The number of failed lookups is
  stored in the database, now and then (avoiding making each lookup a
  database put).

All in all this means clients can be pointed towards a cluster using
just multiple A / AAAA records to gain both load sharing and redundancy
(if one is down, clients will talk to the remaining ones).

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4648
2018-01-14 08:52:31 +00:00

142 lines
4.1 KiB
Go

// +build windows
package pb
import (
"errors"
"fmt"
"os"
"sync"
"syscall"
"unsafe"
)
var tty = os.Stdin
var (
kernel32 = syscall.NewLazyDLL("kernel32.dll")
// GetConsoleScreenBufferInfo retrieves information about the
// specified console screen buffer.
// http://msdn.microsoft.com/en-us/library/windows/desktop/ms683171(v=vs.85).aspx
procGetConsoleScreenBufferInfo = kernel32.NewProc("GetConsoleScreenBufferInfo")
// GetConsoleMode retrieves the current input mode of a console's
// input buffer or the current output mode of a console screen buffer.
// https://msdn.microsoft.com/en-us/library/windows/desktop/ms683167(v=vs.85).aspx
getConsoleMode = kernel32.NewProc("GetConsoleMode")
// SetConsoleMode sets the input mode of a console's input buffer
// or the output mode of a console screen buffer.
// https://msdn.microsoft.com/en-us/library/windows/desktop/ms686033(v=vs.85).aspx
setConsoleMode = kernel32.NewProc("SetConsoleMode")
// SetConsoleCursorPosition sets the cursor position in the
// specified console screen buffer.
// https://msdn.microsoft.com/en-us/library/windows/desktop/ms686025(v=vs.85).aspx
setConsoleCursorPosition = kernel32.NewProc("SetConsoleCursorPosition")
)
type (
// Defines the coordinates of the upper left and lower right corners
// of a rectangle.
// See
// http://msdn.microsoft.com/en-us/library/windows/desktop/ms686311(v=vs.85).aspx
smallRect struct {
Left, Top, Right, Bottom int16
}
// Defines the coordinates of a character cell in a console screen
// buffer. The origin of the coordinate system (0,0) is at the top, left cell
// of the buffer.
// See
// http://msdn.microsoft.com/en-us/library/windows/desktop/ms682119(v=vs.85).aspx
coordinates struct {
X, Y int16
}
word int16
// Contains information about a console screen buffer.
// http://msdn.microsoft.com/en-us/library/windows/desktop/ms682093(v=vs.85).aspx
consoleScreenBufferInfo struct {
dwSize coordinates
dwCursorPosition coordinates
wAttributes word
srWindow smallRect
dwMaximumWindowSize coordinates
}
)
// terminalWidth returns width of the terminal.
func terminalWidth() (width int, err error) {
var info consoleScreenBufferInfo
_, _, e := syscall.Syscall(procGetConsoleScreenBufferInfo.Addr(), 2, uintptr(syscall.Stdout), uintptr(unsafe.Pointer(&info)), 0)
if e != 0 {
return 0, error(e)
}
return int(info.dwSize.X) - 1, nil
}
func getCursorPos() (pos coordinates, err error) {
var info consoleScreenBufferInfo
_, _, e := syscall.Syscall(procGetConsoleScreenBufferInfo.Addr(), 2, uintptr(syscall.Stdout), uintptr(unsafe.Pointer(&info)), 0)
if e != 0 {
return info.dwCursorPosition, error(e)
}
return info.dwCursorPosition, nil
}
func setCursorPos(pos coordinates) error {
_, _, e := syscall.Syscall(setConsoleCursorPosition.Addr(), 2, uintptr(syscall.Stdout), uintptr(uint32(uint16(pos.Y))<<16|uint32(uint16(pos.X))), 0)
if e != 0 {
return error(e)
}
return nil
}
var ErrPoolWasStarted = errors.New("Bar pool was started")
var echoLocked bool
var echoLockMutex sync.Mutex
var oldState word
func lockEcho() (quit chan int, err error) {
echoLockMutex.Lock()
defer echoLockMutex.Unlock()
if echoLocked {
err = ErrPoolWasStarted
return
}
echoLocked = true
if _, _, e := syscall.Syscall(getConsoleMode.Addr(), 2, uintptr(syscall.Stdout), uintptr(unsafe.Pointer(&oldState)), 0); e != 0 {
err = fmt.Errorf("Can't get terminal settings: %v", e)
return
}
newState := oldState
const ENABLE_ECHO_INPUT = 0x0004
const ENABLE_LINE_INPUT = 0x0002
newState = newState & (^(ENABLE_LINE_INPUT | ENABLE_ECHO_INPUT))
if _, _, e := syscall.Syscall(setConsoleMode.Addr(), 2, uintptr(syscall.Stdout), uintptr(newState), 0); e != 0 {
err = fmt.Errorf("Can't set terminal settings: %v", e)
return
}
return
}
func unlockEcho() (err error) {
echoLockMutex.Lock()
defer echoLockMutex.Unlock()
if !echoLocked {
return
}
echoLocked = false
if _, _, e := syscall.Syscall(setConsoleMode.Addr(), 2, uintptr(syscall.Stdout), uintptr(oldState), 0); e != 0 {
err = fmt.Errorf("Can't set terminal settings")
}
return
}