// Forget removes a buddy from the buddy list
func Forget(dependencies *map[string]time.Time, router *ribbon.Router, msg gotocol.Message) {
microservice := msg.Intention // message body is buddy name to forget
if router.Named(microservice) != nil { // an existing buddy to forget
// forget how to talk to this buddy
(*dependencies)[names.Service(microservice)] = msg.Sent // remember when we were told to forget this service
router.Remove(microservice)
}
}
func Put(msg gotocol.Message, name string, listener chan gotocol.Message, requestor *map[string]gotocol.Routetype, router *ribbon.Router) {
// pass on request to a random service - client send
c := router.Random()
if c == nil {
return
}
outmsg := gotocol.Message{gotocol.Put, listener, time.Now(), msg.Ctx.NewParent(), msg.Intention}
flow.AnnotateSend(outmsg, name)
outmsg.GoSend(c)
}
func GetRequest(msg gotocol.Message, name string, listener chan gotocol.Message, requestor *map[string]gotocol.Routetype, router *ribbon.Router) {
// pass on request to a random service - client send
c := router.Random()
if c == nil {
return
}
outmsg := gotocol.Message{gotocol.GetRequest, listener, time.Now(), msg.Ctx.NewParent(), msg.Intention}
flow.AnnotateSend(outmsg, name)
(*requestor)[outmsg.Ctx.Route()] = msg.Route() // remember where to respond to when this span comes back
outmsg.GoSend(c)
}
// NameDrop updates local buddy list
func NameDrop(dependencies *map[string]time.Time, router *ribbon.Router, msg gotocol.Message, name string, listener chan gotocol.Message, eureka map[string]chan gotocol.Message, crosszone ...bool) {
if msg.ResponseChan == nil { // dependency by service name, needs to be looked up in eureka
(*dependencies)[msg.Intention] = msg.Sent // remember it for later
for _, ch := range eureka {
//log.Println(name + " looking up " + msg.Intention)
gotocol.Send(ch, gotocol.Message{gotocol.GetRequest, listener, time.Now(), gotocol.NilContext, msg.Intention})
}
} else { // update dependency with full name and listener channel
microservice := msg.Intention // message body is buddy name
if len(crosszone) > 0 || names.Zone(name) == names.Zone(microservice) {
if microservice != name && router.Named(microservice) == nil { // don't talk to myself or record duplicates
// remember how to talk to this buddy
router.Add(microservice, msg.ResponseChan, msg.Sent) // message channel is buddy's listener
(*dependencies)[names.Service(microservice)] = msg.Sent
for _, ch := range eureka {
// tell just one of the service registries I have a new buddy to talk to so it doesn't get logged more than once
gotocol.Send(ch, gotocol.Message{gotocol.Inform, listener, time.Now(), gotocol.NilContext, name + " " + microservice})
return
}
}
}
}
}
// Start staash, all configuration and state is sent via messages
func Start(listener chan gotocol.Message) {
microservices := ribbon.MakeRouter() // outbound routes
var caches, stores, volumes, cass, staash *ribbon.Router // subsets of the router
dependencies := make(map[string]time.Time) // dependent service names and time last updated
var parent chan gotocol.Message // remember how to talk back to creator
requestor := make(map[string]gotocol.Routetype) // remember where requests came from when responding
var name string // remember my name
eureka := make(map[string]chan gotocol.Message, 1) // service registry
hist := collect.NewHist("")
ep, _ := time.ParseDuration(archaius.Conf.EurekaPoll)
eurekaTicker := time.NewTicker(ep)
for {
select {
case msg := <-listener:
flow.Instrument(msg, name, hist)
switch msg.Imposition {
case gotocol.Hello:
if name == "" {
// if I don't have a name yet remember what I've been named
parent = msg.ResponseChan // remember how to talk to my namer
name = msg.Intention // message body is my name
hist = collect.NewHist(name)
}
case gotocol.Inform:
eureka[msg.Intention] = handlers.Inform(msg, name, listener)
case gotocol.NameDrop:
handlers.NameDrop(&dependencies, microservices, msg, name, listener, eureka, true) // true to setup cross zone routing
caches = microservices.All(CachePkg)
volumes = microservices.All(VolumePkg)
stores = microservices.All(StorePkg)
cass = microservices.All(PriamCassandraPkg)
staash = microservices.All(StaashPkg)
case gotocol.Forget:
// forget a buddy
handlers.Forget(&dependencies, microservices, msg)
caches = microservices.All(CachePkg)
volumes = microservices.All(VolumePkg)
stores = microservices.All(StorePkg)
cass = microservices.All(PriamCassandraPkg)
staash = microservices.All(StaashPkg)
case gotocol.GetRequest:
// route the request on to a cache first if configured
r := gotocol.PickRoute(requestor, msg)
if caches.Len() > 0 {
handlers.GetRequest(msg, name, listener, &requestor, caches)
r.State = cacheLookup
} else {
// route to any volumes if configured
if volumes.Len() > 0 {
handlers.GetRequest(msg, name, listener, &requestor, volumes)
r.State = volumeLookup
} else {
// route to any cassandra if configured
if cass.Len() > 0 {
handlers.GetRequest(msg, name, listener, &requestor, cass)
r.State = cassandraLookup
} else {
// route to stores if configured
if stores.Len() > 0 {
handlers.GetRequest(msg, name, listener, &requestor, stores)
r.State = storeLookup
} else {
// route to more staash layers if configured
if staash.Len() > 0 {
handlers.GetRequest(msg, name, listener, &requestor, staash)
r.State = staashLookup
}
}
}
}
}
//log.Printf("%v: %v route: %v", name, msg.Context, r)
case gotocol.GetResponse:
// return path from a request, resend or send payload back up using saved span context - server send
r := gotocol.PickRoute(requestor, msg)
if msg.Intention != "" { // we got a value, so pass it back up
handlers.GetResponse(msg, name, listener, &requestor)
} else {
switch r.State {
case cacheLookup:
if volumes.Len() > 0 {
handlers.GetRequest(msg, name, listener, &requestor, volumes)
r.State = volumeLookup
break
}
fallthrough // no volumes so look for cassandra
case volumeLookup:
if cass.Len() > 0 {
handlers.GetRequest(msg, name, listener, &requestor, cass)
r.State = cassandraLookup
break
}
fallthrough // no cassandra so look for stores
case cassandraLookup:
if stores.Len() > 0 {
handlers.GetRequest(msg, name, listener, &requestor, stores)
r.State = storeLookup
break
}
fallthrough // no stores
case storeLookup:
if staash.Len() > 0 {
handlers.GetRequest(msg, name, listener, &requestor, staash)
r.State = staashLookup
break
}
fallthrough // no staash
case staashLookup:
// ran out of options to find anything so pass empty response back up
handlers.GetResponse(msg, name, listener, &requestor)
case newRequest:
default:
}
}
case gotocol.Put:
// duplicate the request to any cache, volumes, stores, and cassandra but only to one of each type
// storage class packages sideways Replicate if configured
// to get a lossy write, configure multiple stores that don't cross replicate
handlers.Put(msg, name, listener, &requestor, caches)
handlers.Put(msg, name, listener, &requestor, cass)
handlers.Put(msg, name, listener, &requestor, staash)
handlers.Put(msg, name, listener, &requestor, stores)
msg.Intention = names.Instance(name) + "/" + msg.Intention // store to an instance specific volume namespace
handlers.Put(msg, name, listener, &requestor, volumes)
case gotocol.Goodbye:
for _, ch := range eureka { // tell name service I'm not going to be here
ch <- gotocol.Message{gotocol.Delete, nil, time.Now(), gotocol.NilContext, name}
}
gotocol.Message{gotocol.Goodbye, nil, time.Now(), gotocol.NilContext, name}.GoSend(parent)
return
}
case <-eurekaTicker.C: // check to see if any new dependencies have appeared
for dep, _ := range dependencies {
for _, ch := range eureka {
ch <- gotocol.Message{gotocol.GetRequest, listener, time.Now(), gotocol.NilContext, dep}
}
}
}
}
}
