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https://github.com/redis/go-redis.git
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0ef6d0727d
- Adds support for handling push notifications with RESP3. - Using this support adds handlers for hitless upgrades. --------- Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> Co-authored-by: Hristo Temelski <hristo.temelski@redis.com>
60 lines
1.3 KiB
Go
60 lines
1.3 KiB
Go
//go:build linux || darwin || dragonfly || freebsd || netbsd || openbsd || solaris || illumos
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package pool
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import (
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"errors"
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"io"
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"net"
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"syscall"
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"time"
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)
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var errUnexpectedRead = errors.New("unexpected read from socket")
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// connCheck checks if the connection is still alive and if there is data in the socket
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// it will try to peek at the next byte without consuming it since we may want to work with it
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// later on (e.g. push notifications)
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func connCheck(conn net.Conn) error {
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// Reset previous timeout.
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_ = conn.SetDeadline(time.Time{})
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sysConn, ok := conn.(syscall.Conn)
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if !ok {
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return nil
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}
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rawConn, err := sysConn.SyscallConn()
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if err != nil {
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return err
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}
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var sysErr error
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if err := rawConn.Read(func(fd uintptr) bool {
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var buf [1]byte
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// Use MSG_PEEK to peek at data without consuming it
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n, _, err := syscall.Recvfrom(int(fd), buf[:], syscall.MSG_PEEK|syscall.MSG_DONTWAIT)
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switch {
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case n == 0 && err == nil:
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sysErr = io.EOF
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case n > 0:
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sysErr = errUnexpectedRead
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case err == syscall.EAGAIN || err == syscall.EWOULDBLOCK:
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sysErr = nil
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default:
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sysErr = err
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}
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return true
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}); err != nil {
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return err
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}
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return sysErr
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}
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// maybeHasData checks if there is data in the socket without consuming it
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func maybeHasData(conn net.Conn) bool {
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return connCheck(conn) == errUnexpectedRead
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}
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