From af48d9a1bc24d14e113571a80c19dfaaf203c87c Mon Sep 17 00:00:00 2001 From: Alan Pearce Date: Tue, 2 Jul 2024 11:00:36 +0200 Subject: listenfd: init --- listenfd/listenfd.go | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) create mode 100644 listenfd/listenfd.go (limited to 'listenfd') diff --git a/listenfd/listenfd.go b/listenfd/listenfd.go new file mode 100644 index 0000000..cbf3163 --- /dev/null +++ b/listenfd/listenfd.go @@ -0,0 +1,71 @@ +package listenfd + +import ( + "crypto/tls" + "net" + "os" + "strconv" + + "go.alanpearce.eu/x/log" + + "gitlab.com/tozd/go/errors" +) + +const fdStart = 3 + +func GetListener(i uint64, addr string, log *log.Logger) (l net.Listener, err error) { + l, err = getFDSocket(i) + if err != nil { + log.Warn("could not create listener from listenfd", "error", err) + } + + log.Debug("listener from listenfd?", "passed", l != nil) + if l == nil { + l, err = net.Listen("tcp", addr) + if err != nil { + return nil, errors.Wrap(err, "could not create listener") + } + } + + return +} + +func GetListenerTLS( + i uint64, + addr string, + config *tls.Config, + log *log.Logger, +) (l net.Listener, err error) { + l, err = GetListener(i, addr, log) + if err != nil { + return nil, err + } + + return tls.NewListener(l, config), nil +} + +func getFDSocket(i uint64) (net.Listener, error) { + lfds, present := os.LookupEnv("LISTEN_FDS") + if !present { + return nil, nil + } + err := os.Unsetenv("LISTEN_FDS") + if err != nil { + return nil, errors.Wrap(err, "could not unset LISTEN_FDS") + } + + fds, err := strconv.ParseUint(lfds, 10, 32) + if err != nil { + return nil, errors.Wrap(err, "could not parse LISTEN_FDS") + } + if i >= fds { + return nil, errors.Errorf("only %d fds available, requested index %d", fds, i) + } + + l, err := net.FileListener(os.NewFile(uintptr(i+fdStart), "")) + if err != nil { + return nil, errors.Wrap(err, "could not create listener") + } + + return l, nil +} -- cgit 1.4.1