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Merge pull request #416 from jiyeyuran/patch-4

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reuse rcache
This commit is contained in:
Asim Aslam 2019-02-13 09:58:49 +00:00 committed by GitHub
commit 0cdae40f04
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1 changed files with 17 additions and 378 deletions
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393
selector/default.go
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@ -1,359 +1,25 @@
package selector
import (
"sync"
"time"
"github.com/micro/go-log"
"github.com/micro/go-micro/registry"
"github.com/micro/go-rcache"
)
type registrySelector struct {
so Options
ttl time.Duration
// registry cache
sync.RWMutex
cache map[string][]*registry.Service
ttls map[string]time.Time
watched map[string]bool
// used to close or reload watcher
reload chan bool
exit chan bool
rc rcache.Cache
}
var (
DefaultTTL = time.Minute
)
// isValid checks if the service is valid
func (c *registrySelector) isValid(services []*registry.Service, ttl time.Time) bool {
// no services exist
if len(services) == 0 {
return false
}
// ttl is invalid
if ttl.IsZero() {
return false
}
// time since ttl is longer than timeout
if time.Since(ttl) > c.ttl {
return false
}
// ok
return true
}
func (c *registrySelector) quit() bool {
select {
case <-c.exit:
return true
default:
return false
func (c *registrySelector) newRCache() rcache.Cache {
ropts := []rcache.Option{}
if c.so.Context != nil {
if t, ok := c.so.Context.Value("selector_ttl").(time.Duration); ok {
ropts = append(ropts, rcache.WithTTL(t))
}
}
// cp copies a service. Because we're caching handing back pointers would
// create a race condition, so we do this instead
// its fast enough
func (c *registrySelector) cp(current []*registry.Service) []*registry.Service {
var services []*registry.Service
for _, service := range current {
// copy service
s := new(registry.Service)
*s = *service
// copy nodes
var nodes []*registry.Node
for _, node := range service.Nodes {
n := new(registry.Node)
*n = *node
nodes = append(nodes, n)
}
s.Nodes = nodes
// copy endpoints
var eps []*registry.Endpoint
for _, ep := range service.Endpoints {
e := new(registry.Endpoint)
*e = *ep
eps = append(eps, e)
}
s.Endpoints = eps
// append service
services = append(services, s)
}
return services
}
func (c *registrySelector) del(service string) {
delete(c.cache, service)
delete(c.ttls, service)
}
func (c *registrySelector) get(service string) ([]*registry.Service, error) {
// read lock
c.RLock()
// check the cache first
services := c.cache[service]
// get cache ttl
ttl := c.ttls[service]
// got services && within ttl so return cache
if c.isValid(services, ttl) {
// make a copy
cp := c.cp(services)
// unlock the read
c.RUnlock()
// return servics
return cp, nil
}
// get does the actual request for a service and cache it
get := func(service string) ([]*registry.Service, error) {
// ask the registry
services, err := c.so.Registry.GetService(service)
if err != nil {
return nil, err
}
// cache results
c.Lock()
c.set(service, c.cp(services))
c.Unlock()
return services, nil
}
// watch service if not watched
if _, ok := c.watched[service]; !ok {
go c.run(service)
}
// unlock the read lock
c.RUnlock()
// get and return services
return get(service)
}
func (c *registrySelector) set(service string, services []*registry.Service) {
c.cache[service] = services
c.ttls[service] = time.Now().Add(c.ttl)
}
func (c *registrySelector) update(res *registry.Result) {
if res == nil || res.Service == nil {
return
}
c.Lock()
defer c.Unlock()
services, ok := c.cache[res.Service.Name]
if !ok {
// we're not going to cache anything
// unless there was already a lookup
return
}
if len(res.Service.Nodes) == 0 {
switch res.Action {
case "delete":
c.del(res.Service.Name)
}
return
}
// existing service found
var service *registry.Service
var index int
for i, s := range services {
if s.Version == res.Service.Version {
service = s
index = i
}
}
switch res.Action {
case "create", "update":
if service == nil {
c.set(res.Service.Name, append(services, res.Service))
return
}
// append old nodes to new service
for _, cur := range service.Nodes {
var seen bool
for _, node := range res.Service.Nodes {
if cur.Id == node.Id {
seen = true
break
}
}
if !seen {
res.Service.Nodes = append(res.Service.Nodes, cur)
}
}
services[index] = res.Service
c.set(res.Service.Name, services)
case "delete":
if service == nil {
return
}
var nodes []*registry.Node
// filter cur nodes to remove the dead one
for _, cur := range service.Nodes {
var seen bool
for _, del := range res.Service.Nodes {
if del.Id == cur.Id {
seen = true
break
}
}
if !seen {
nodes = append(nodes, cur)
}
}
// still got nodes, save and return
if len(nodes) > 0 {
service.Nodes = nodes
services[index] = service
c.set(service.Name, services)
return
}
// zero nodes left
// only have one thing to delete
// nuke the thing
if len(services) == 1 {
c.del(service.Name)
return
}
// still have more than 1 service
// check the version and keep what we know
var srvs []*registry.Service
for _, s := range services {
if s.Version != service.Version {
srvs = append(srvs, s)
}
}
// save
c.set(service.Name, srvs)
}
}
// run starts the cache watcher loop
// it creates a new watcher if there's a problem
// reloads the watcher if Init is called
// and returns when Close is called
func (c *registrySelector) run(name string) {
// set watcher
c.Lock()
c.watched[name] = true
c.Unlock()
// delete watcher on exit
defer func() {
c.Lock()
delete(c.watched, name)
c.Unlock()
}()
// error counter
var cerr int
for {
// exit early if already dead
if c.quit() {
return
}
// create new watcher
w, err := c.so.Registry.Watch(
registry.WatchService(name),
)
if err != nil {
if c.quit() {
return
}
cerr++
if cerr > 3 {
log.Log(err)
cerr = 0
}
time.Sleep(time.Second)
continue
}
// watch for events
if err := c.watch(w); err != nil {
if c.quit() {
return
}
cerr++
if cerr > 3 {
cerr = 0
log.Log(err)
}
continue
}
// reset err counter
cerr = 0
}
}
// watch loops the next event and calls update
// it returns if there's an error
func (c *registrySelector) watch(w registry.Watcher) error {
defer w.Stop()
// reload chan
reload := make(chan bool, 1)
// manage this loop
go func() {
// wait for exit or reload signal
select {
case <-c.exit:
case <-c.reload:
reload <- true
}
// stop the watcher
w.Stop()
}()
for {
res, err := w.Next()
if err != nil {
select {
case <-reload:
return nil
default:
return err
}
}
c.update(res)
}
return rcache.New(c.so.Registry, ropts...)
}
func (c *registrySelector) Init(opts ...Option) error {
@ -361,15 +27,8 @@ func (c *registrySelector) Init(opts ...Option) error {
o(&c.so)
}
// reload the watcher
go func() {
select {
case <-c.exit:
return
default:
c.reload <- true
}
}()
c.rc.Stop()
c.rc = c.newRCache()
return nil
}
@ -390,7 +49,7 @@ func (c *registrySelector) Select(service string, opts ...SelectOption) (Next, e
// get the service
// try the cache first
// if that fails go directly to the registry
services, err := c.get(service)
services, err := c.rc.GetService(service)
if err != nil {
return nil, err
}
@ -416,17 +75,8 @@ func (c *registrySelector) Reset(service string) {
// Close stops the watcher and destroys the cache
func (c *registrySelector) Close() error {
c.Lock()
c.cache = make(map[string][]*registry.Service)
c.watched = make(map[string]bool)
c.Unlock()
c.rc.Stop()
select {
case <-c.exit:
return nil
default:
close(c.exit)
}
return nil
}
@ -447,21 +97,10 @@ func NewSelector(opts ...Option) Selector {
sopts.Registry = registry.DefaultRegistry
}
ttl := DefaultTTL
if sopts.Context != nil {
if t, ok := sopts.Context.Value("selector_ttl").(time.Duration); ok {
ttl = t
}
}
return &registrySelector{
s := &registrySelector{
so: sopts,
ttl: ttl,
watched: make(map[string]bool),
cache: make(map[string][]*registry.Service),
ttls: make(map[string]time.Time),
reload: make(chan bool, 1),
exit: make(chan bool),
}
s.rc = s.newRCache()
return s
}