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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
}
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
}
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