/
service_resolver.go
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/
service_resolver.go
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// The MIT License
//
// Copyright (c) 2020 Temporal Technologies Inc. All rights reserved.
//
// Copyright (c) 2020 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package ringpop
import (
"errors"
"net"
"strconv"
"sync"
"sync/atomic"
"time"
"github.com/temporalio/ringpop-go"
"github.com/temporalio/tchannel-go"
"github.com/dgryski/go-farm"
"github.com/temporalio/ringpop-go/events"
"github.com/temporalio/ringpop-go/hashring"
"github.com/temporalio/ringpop-go/swim"
"go.temporal.io/server/common"
"go.temporal.io/server/common/log"
"go.temporal.io/server/common/log/tag"
"go.temporal.io/server/common/membership"
"go.temporal.io/server/common/primitives"
"go.temporal.io/server/common/util"
)
const (
// roleKey label is set by every single service as soon as it bootstraps its
// ringpop instance. The data for this key is the service name
roleKey = "serviceName"
// rolePort label is set by every single service as soon as it bootstraps its
// ringpop instance. The data for this key represents the TCP port through which
// the service can be accessed.
rolePort = "servicePort"
minRefreshInternal = time.Second * 4
defaultRefreshInterval = time.Second * 10
replicaPoints = 100
)
type serviceResolver struct {
service primitives.ServiceName
port int
rp *ringpop.Ringpop
refreshChan chan struct{}
shutdownCh chan struct{}
shutdownWG sync.WaitGroup
logger log.Logger
ringValue atomic.Value // this stores the current hashring
refreshLock sync.Mutex
lastRefreshTime time.Time
membersMap map[string]struct{} // for de-duping change notifications
listenerLock sync.RWMutex
listeners map[string]chan<- *membership.ChangedEvent
}
var _ membership.ServiceResolver = (*serviceResolver)(nil)
func newServiceResolver(
service primitives.ServiceName,
port int,
rp *ringpop.Ringpop,
logger log.Logger,
) *serviceResolver {
resolver := &serviceResolver{
service: service,
port: port,
rp: rp,
refreshChan: make(chan struct{}),
shutdownCh: make(chan struct{}),
logger: log.With(logger, tag.ComponentServiceResolver, tag.Service(service)),
membersMap: make(map[string]struct{}),
listeners: make(map[string]chan<- *membership.ChangedEvent),
}
resolver.ringValue.Store(newHashRing())
return resolver
}
func newHashRing() *hashring.HashRing {
return hashring.New(farm.Fingerprint32, replicaPoints)
}
// Start starts the oracle
func (r *serviceResolver) Start() {
r.rp.AddListener(r)
if err := r.refresh(); err != nil {
r.logger.Fatal("unable to start ring pop service resolver", tag.Error(err))
}
r.shutdownWG.Add(1)
go r.refreshRingWorker()
}
// Stop stops the resolver
func (r *serviceResolver) Stop() {
r.listenerLock.Lock()
defer r.listenerLock.Unlock()
r.rp.RemoveListener(r)
r.ringValue.Store(newHashRing())
r.listeners = make(map[string]chan<- *membership.ChangedEvent)
close(r.shutdownCh)
if success := common.AwaitWaitGroup(&r.shutdownWG, time.Minute); !success {
r.logger.Warn("service resolver timed out on shutdown.")
}
}
func (r *serviceResolver) RequestRefresh() {
select {
case r.refreshChan <- struct{}{}:
default:
}
}
// Lookup finds the host in the ring responsible for serving the given key
func (r *serviceResolver) Lookup(key string) (membership.HostInfo, error) {
addr, found := r.ring().Lookup(key)
if !found {
r.RequestRefresh()
return nil, membership.ErrInsufficientHosts
}
return newHostInfo(addr, r.getLabelsMap()), nil
}
func (r *serviceResolver) LookupN(key string, n int) []membership.HostInfo {
if n <= 0 {
return nil
}
addresses := r.ring().LookupN(key, n)
if len(addresses) == 0 {
r.RequestRefresh()
return nil
}
labels := r.getLabelsMap()
return util.MapSlice(addresses, func(address string) membership.HostInfo { return newHostInfo(address, labels) })
}
func (r *serviceResolver) AddListener(
name string,
notifyChannel chan<- *membership.ChangedEvent,
) error {
r.listenerLock.Lock()
defer r.listenerLock.Unlock()
_, ok := r.listeners[name]
if ok {
return membership.ErrListenerAlreadyExist
}
r.listeners[name] = notifyChannel
return nil
}
func (r *serviceResolver) RemoveListener(
name string,
) error {
r.listenerLock.Lock()
defer r.listenerLock.Unlock()
_, ok := r.listeners[name]
if !ok {
return nil
}
delete(r.listeners, name)
return nil
}
func (r *serviceResolver) MemberCount() int {
return r.ring().ServerCount()
}
func (r *serviceResolver) Members() []membership.HostInfo {
var servers []membership.HostInfo
for _, s := range r.ring().Servers() {
servers = append(servers, newHostInfo(s, r.getLabelsMap()))
}
return servers
}
// HandleEvent handles updates from ringpop
func (r *serviceResolver) HandleEvent(
event events.Event,
) {
// We only care about RingChangedEvent
if _, ok := event.(events.RingChangedEvent); ok {
r.logger.Debug("Received a ring changed event")
// Note that we receive events asynchronously, possibly out of order.
// We cannot rely on the content of the event, rather we load everything
// from ringpop when we get a notification that something changed.
if err := r.refresh(); err != nil {
r.logger.Error("error refreshing ring when receiving a ring changed event", tag.Error(err))
}
}
}
func (r *serviceResolver) refresh() error {
var event *membership.ChangedEvent
var err error
defer func() {
if event != nil {
r.emitEvent(event)
}
}()
r.refreshLock.Lock()
defer r.refreshLock.Unlock()
event, err = r.refreshNoLock()
return err
}
func (r *serviceResolver) refreshWithBackoff() error {
var event *membership.ChangedEvent
var err error
defer func() {
if event != nil {
r.emitEvent(event)
}
}()
r.refreshLock.Lock()
defer r.refreshLock.Unlock()
if r.lastRefreshTime.After(time.Now().UTC().Add(-minRefreshInternal)) {
// refresh too frequently
return nil
}
event, err = r.refreshNoLock()
return err
}
func (r *serviceResolver) refreshNoLock() (*membership.ChangedEvent, error) {
addrs, err := r.getReachableMembers()
if err != nil {
return nil, err
}
newMembersMap, changedEvent := r.compareMembers(addrs)
if changedEvent == nil {
return nil, nil
}
ring := newHashRing()
for _, addr := range addrs {
host := newHostInfo(addr, r.getLabelsMap())
ring.AddMembers(host)
}
r.membersMap = newMembersMap
r.lastRefreshTime = time.Now().UTC()
r.ringValue.Store(ring)
r.logger.Info("Current reachable members", tag.Addresses(addrs))
return changedEvent, nil
}
func (r *serviceResolver) getReachableMembers() ([]string, error) {
members, err := r.rp.GetReachableMemberObjects(swim.MemberWithLabelAndValue(roleKey, string(r.service)))
if err != nil {
return nil, err
}
var hostPorts []string
for _, member := range members {
servicePort := r.port
// Each temporal service in the ring should advertise which port it has its gRPC listener
// on via a service label. If we cannot find the label, we will assume that the
// temporal service is listening on the same port that this node is listening on.
servicePortLabel, ok := member.Label(rolePort)
if ok {
servicePort, err = strconv.Atoi(servicePortLabel)
if err != nil {
return nil, err
}
} else {
r.logger.Debug("unable to find roleport label for ringpop member. using local service's port", tag.Service(r.service))
}
hostPort, err := replaceServicePort(member.Address, servicePort)
if err != nil {
return nil, err
}
hostPorts = append(hostPorts, hostPort)
}
return hostPorts, nil
}
func (r *serviceResolver) emitEvent(event *membership.ChangedEvent) {
// Notify listeners
r.listenerLock.RLock()
defer r.listenerLock.RUnlock()
for name, ch := range r.listeners {
select {
case ch <- event:
default:
r.logger.Error("Failed to send listener notification, channel full", tag.ListenerName(name))
}
}
}
func (r *serviceResolver) refreshRingWorker() {
defer r.shutdownWG.Done()
refreshTicker := time.NewTicker(defaultRefreshInterval)
defer refreshTicker.Stop()
for {
select {
case <-r.shutdownCh:
return
case <-r.refreshChan:
if err := r.refreshWithBackoff(); err != nil {
r.logger.Error("error refreshing ring by request", tag.Error(err))
}
case <-refreshTicker.C:
if err := r.refreshWithBackoff(); err != nil {
r.logger.Error("error periodically refreshing ring", tag.Error(err))
}
}
}
}
func (r *serviceResolver) ring() *hashring.HashRing {
return r.ringValue.Load().(*hashring.HashRing)
}
func (r *serviceResolver) getLabelsMap() map[string]string {
labels := make(map[string]string)
labels[roleKey] = string(r.service)
return labels
}
func (r *serviceResolver) compareMembers(addrs []string) (map[string]struct{}, *membership.ChangedEvent) {
event := &membership.ChangedEvent{}
changed := false
newMembersMap := make(map[string]struct{}, len(addrs))
for _, addr := range addrs {
newMembersMap[addr] = struct{}{}
if _, ok := r.membersMap[addr]; !ok {
event.HostsAdded = append(event.HostsAdded, newHostInfo(addr, r.getLabelsMap()))
changed = true
}
}
for addr := range r.membersMap {
if _, ok := newMembersMap[addr]; !ok {
event.HostsRemoved = append(event.HostsRemoved, newHostInfo(addr, r.getLabelsMap()))
changed = true
}
}
if changed {
return newMembersMap, event
}
return newMembersMap, nil
}
// buildBroadcastHostPort return the listener hostport from an existing tchannel
// and overrides the address with broadcastAddress if specified
func buildBroadcastHostPort(listenerPeerInfo tchannel.LocalPeerInfo, broadcastAddress string) (string, error) {
// Ephemeral port check copied from ringpop-go/ringpop.go/channelAddressResolver
// Check that TChannel is listening on a real hostport. By default,
// TChannel listens on an ephemeral host/port. The real port is then
// assigned by the OS when ListenAndServe is called. If the hostport is
// ephemeral, it means TChannel is not yet listening and the hostport
// cannot be resolved.
if listenerPeerInfo.IsEphemeralHostPort() {
return "", ringpop.ErrEphemeralAddress
}
// Parse listener hostport
listenerIPString, port, err := net.SplitHostPort(listenerPeerInfo.HostPort)
if err != nil {
return "", err
}
// Broadcast IP override
if broadcastAddress != "" {
// Parse supplied broadcastAddress override
ip := net.ParseIP(broadcastAddress)
if ip == nil {
return "", errors.New("broadcastAddress set but unknown failure encountered while parsing")
}
// If no errors, use the parsed IP with the port from our listener
return net.JoinHostPort(ip.String(), port), nil
}
listenerIP := net.ParseIP(listenerIPString)
if listenerIP == nil {
return "", errors.New("unable to parse listenerIP")
}
if listenerIP.IsUnspecified() {
return "", errors.New("broadcastAddress required when listening on all interfaces (0.0.0.0/[::])")
}
return listenerPeerInfo.HostPort, nil
}