/
watcher.go
226 lines (187 loc) · 4.76 KB
/
watcher.go
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package redis_discovery
import (
"context"
"errors"
"fmt"
"git.golaxy.org/framework/plugins/discovery"
"git.golaxy.org/framework/plugins/log"
"github.com/redis/go-redis/v9"
"net"
"strings"
)
func (r *_Registry) newWatcher(ctx context.Context, pattern string) (watcher *_Watcher, err error) {
if ctx == nil {
ctx = context.Background()
}
ctx, cancel := context.WithCancel(ctx)
var keyPath string
if pattern != "" {
keyPath = getServicePath(r.options.KeyPrefix, pattern)
} else {
keyPath = r.options.KeyPrefix + "*"
}
watchPathPrefixList := []string{
fmt.Sprintf("__keyspace@%d__:", r.client.Options().DB),
fmt.Sprintf("__keyevent@%d__:", r.client.Options().DB),
}
watchPathList := []string{
watchPathPrefixList[0] + keyPath,
watchPathPrefixList[1] + "expired",
}
pubSub := r.client.PSubscribe(ctx)
defer func() {
if err != nil {
pubSub.Close()
}
}()
if err := pubSub.PSubscribe(ctx, watchPathList...); err != nil {
return nil, fmt.Errorf("registry: %w", err)
}
keys, err := r.client.Keys(ctx, keyPath).Result()
if err != nil {
return nil, fmt.Errorf("registry: %w", err)
}
keyCache := map[string]string{}
if len(keys) > 0 {
values, err := r.client.MGet(ctx, keys...).Result()
if err != nil {
return nil, fmt.Errorf("registry: %w", err)
}
for i, v := range values {
if v != nil {
keyCache[keys[i]] = v.(string)
}
}
}
eventChan := make(chan *discovery.Event, r.options.WatchChanSize)
watcher = &_Watcher{
registry: r,
ctx: ctx,
terminate: cancel,
terminatedChan: make(chan struct{}),
pattern: keyPath,
pathPrefixList: watchPathPrefixList,
pathList: watchPathList,
keyCache: keyCache,
pubSub: pubSub,
eventChan: eventChan,
}
go watcher.mainLoop()
return watcher, nil
}
type _Watcher struct {
registry *_Registry
ctx context.Context
terminate context.CancelFunc
terminatedChan chan struct{}
pattern string
pathPrefixList []string
pathList []string
keyCache map[string]string
pubSub *redis.PubSub
eventChan chan *discovery.Event
}
// Pattern watching pattern
func (w *_Watcher) Pattern() string {
return strings.TrimPrefix(w.pattern, w.registry.options.KeyPrefix)
}
// Next is a blocking call
func (w *_Watcher) Next() (*discovery.Event, error) {
for event := range w.eventChan {
return event, nil
}
return nil, discovery.ErrTerminated
}
// Terminate stop watching
func (w *_Watcher) Terminate() <-chan struct{} {
w.terminate()
return w.terminatedChan
}
func (w *_Watcher) mainLoop() {
defer func() {
w.terminate()
close(w.eventChan)
close(w.terminatedChan)
}()
log.Debugf(w.registry.servCtx, "start watch %q", w.pathList)
go func() {
<-w.ctx.Done()
w.pubSub.Close()
}()
loop:
for {
msg, err := w.pubSub.ReceiveMessage(context.Background())
if err != nil {
if errors.Is(err, net.ErrClosed) {
log.Debugf(w.registry.servCtx, "stop watch %q, %s", w.pathList, err)
break loop
}
log.Errorf(w.registry.servCtx, "interrupt watch %q, %s", w.pathList, err)
break loop
}
var key, opt string
switch msg.Pattern {
case w.pathList[0]:
key = strings.TrimPrefix(msg.Channel, w.pathPrefixList[0])
opt = msg.Payload
case w.pathList[1]:
key = msg.Payload
opt = strings.TrimPrefix(msg.Channel, w.pathPrefixList[1])
default:
continue
}
if !strings.HasPrefix(key, w.pattern[:len(w.pattern)-1]) {
continue
}
event := &discovery.Event{}
switch opt {
case "set":
val, err := w.registry.client.Get(w.ctx, key).Result()
if err != nil {
if errors.Is(err, context.Canceled) {
continue
}
log.Errorf(w.registry.servCtx, "get service node %q data failed, %s", key, err)
continue
}
_, ok := w.keyCache[key]
if ok {
event.Type = discovery.Update
} else {
event.Type = discovery.Create
}
event.Service, err = decodeService([]byte(val))
if err != nil {
log.Errorf(w.registry.servCtx, "decode service %q data failed, %s", val, err)
continue
}
w.keyCache[key] = val
case "del", "expired":
v, ok := w.keyCache[key]
if !ok {
log.Errorf(w.registry.servCtx, "service node %q data not cached", key)
continue
}
delete(w.keyCache, key)
event.Type = discovery.Delete
event.Service, err = decodeService([]byte(v))
if err != nil {
log.Errorf(w.registry.servCtx, "decode service %q data failed, %s", v, err)
continue
}
default:
continue
}
if len(event.Service.Nodes) <= 0 {
log.Warnf(w.registry.servCtx, "event service %q node is empty, discard it", event.Service.Name)
continue
}
select {
case w.eventChan <- event:
case <-w.ctx.Done():
log.Debugf(w.registry.servCtx, "stop watch %q", w.pathList)
break loop
}
}
w.pubSub.Close()
}