package listenfd import ( "crypto/tls" "net" "os" "strconv" "website/internal/log" "github.com/pkg/errors" ) const fdStart = 3 func GetListener(i uint64, addr string) (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) (l net.Listener, err error) { l, err = GetListener(i, addr) 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 }