// sendOneInvite sends invitations to all the addresses in addrs and returns the one that accepted it.
// All addrs are assumed to be equivalent and thus at most one Invite RPC will succeed.
//
// TODO: This is aiming to replicate what the RPC stack does for all the
// addresses a single name resolved to. Should all these addresses discovered
// somehow be encapsulated in a single object name?
func sendOneInvite(ctx *context.T, addrs []string) string {
// Give at most 1 second for these connections to be made, if they
// can't be made then consider the peer bad and ignore it.
// TODO: Should these RPCs also use the "connection timeout" that might be implemented
// as per proposal: https://docs.google.com/a/google.com/document/d/1prtxGhSR5TaL0lc_iDRC0Q6H1Drbg2T0x7MWVb_ZCSM/edit?usp=sharing
ctx, cancel := context.WithTimeout(ctx, maxInvitationWaitTime)
defer cancel()
ch := make(chan string)
for _, addr := range addrs {
go func(addr string) {
err := spec.ScreenClient(addr).Invite(ctx, options.ServerAuthorizer{security.AllowEveryone()})
ctx.Infof("Invitation to %v sent, error: %v", addr, err)
if err == nil {
ch <- addr
return
}
ch <- ""
}(addr)
}
for i := range addrs {
if ret := <-ch; len(ret) > 0 {
// Drain the rest and return
go func() {
i++
for i < len(addrs) {
<-ch
}
}()
return ret
}
}
return ""
}
func channel2rpc(ctx *context.T, src <-chan *spec.Triangle, dst string, errch chan<- error, myScreen chan<- *spec.Triangle) {
for t := range src {
// This is an "interactive" game, if an RPC doesn't succeed in say
ctxTimeout, cancel := context.WithTimeout(ctx, maxTriangleGiveTime)
if err := spec.ScreenClient(dst).Give(ctxTimeout, *t, options.ServerAuthorizer{security.AllowEveryone()}); err != nil {
cancel()
returnTriangle(t, myScreen)
ctx.Infof("%q.Give failed: %v, aborting connection with remote screen", dst, err)
errch <- err
break
}
cancel()
}
for t := range src {
returnTriangle(t, myScreen)
}
ctx.VI(1).Infof("Exiting goroutine with connection to %q", dst)
}