916ec63af6
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
98 lines
2.8 KiB
Go
98 lines
2.8 KiB
Go
// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build windows
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// Package terminal provides support functions for dealing with terminals, as
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// commonly found on UNIX systems.
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//
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// Putting a terminal into raw mode is the most common requirement:
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//
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// oldState, err := terminal.MakeRaw(0)
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// if err != nil {
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// panic(err)
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// }
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// defer terminal.Restore(0, oldState)
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package terminal
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import (
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"os"
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"golang.org/x/sys/windows"
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)
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type State struct {
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mode uint32
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}
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// IsTerminal returns true if the given file descriptor is a terminal.
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func IsTerminal(fd int) bool {
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var st uint32
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err := windows.GetConsoleMode(windows.Handle(fd), &st)
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return err == nil
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}
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// MakeRaw put the terminal connected to the given file descriptor into raw
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// mode and returns the previous state of the terminal so that it can be
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// restored.
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func MakeRaw(fd int) (*State, error) {
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var st uint32
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if err := windows.GetConsoleMode(windows.Handle(fd), &st); err != nil {
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return nil, err
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}
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raw := st &^ (windows.ENABLE_ECHO_INPUT | windows.ENABLE_PROCESSED_INPUT | windows.ENABLE_LINE_INPUT | windows.ENABLE_PROCESSED_OUTPUT)
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if err := windows.SetConsoleMode(windows.Handle(fd), raw); err != nil {
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return nil, err
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}
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return &State{st}, nil
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}
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// GetState returns the current state of a terminal which may be useful to
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// restore the terminal after a signal.
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func GetState(fd int) (*State, error) {
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var st uint32
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if err := windows.GetConsoleMode(windows.Handle(fd), &st); err != nil {
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return nil, err
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}
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return &State{st}, nil
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}
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// Restore restores the terminal connected to the given file descriptor to a
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// previous state.
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func Restore(fd int, state *State) error {
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return windows.SetConsoleMode(windows.Handle(fd), state.mode)
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}
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// GetSize returns the dimensions of the given terminal.
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func GetSize(fd int) (width, height int, err error) {
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var info windows.ConsoleScreenBufferInfo
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if err := windows.GetConsoleScreenBufferInfo(windows.Handle(fd), &info); err != nil {
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return 0, 0, err
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}
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return int(info.Size.X), int(info.Size.Y), nil
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}
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// ReadPassword reads a line of input from a terminal without local echo. This
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// is commonly used for inputting passwords and other sensitive data. The slice
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// returned does not include the \n.
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func ReadPassword(fd int) ([]byte, error) {
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var st uint32
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if err := windows.GetConsoleMode(windows.Handle(fd), &st); err != nil {
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return nil, err
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}
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old := st
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st &^= (windows.ENABLE_ECHO_INPUT)
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st |= (windows.ENABLE_PROCESSED_INPUT | windows.ENABLE_LINE_INPUT | windows.ENABLE_PROCESSED_OUTPUT)
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if err := windows.SetConsoleMode(windows.Handle(fd), st); err != nil {
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return nil, err
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}
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defer func() {
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windows.SetConsoleMode(windows.Handle(fd), old)
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}()
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return readPasswordLine(os.NewFile(uintptr(fd), "stdin"))
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}
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