113 lines
2.3 KiB
Go
113 lines
2.3 KiB
Go
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package roundrobin
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import (
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"sort"
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"sync"
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"time"
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"github.com/micro/go-micro/v2/router"
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"github.com/micro/go-micro/v2/selector"
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)
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var routeTTL = time.Minute * 15
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// NewSelector returns an initalised round robin selector
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func NewSelector(opts ...selector.Option) selector.Selector {
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r := &roundrobin{
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routes: make(map[uint64]time.Time),
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ticker: time.NewTicker(time.Minute),
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}
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go r.cleanRoutes()
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return r
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}
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type roundrobin struct {
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ticker *time.Ticker
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// routes is a map with the key being a route's hash and the value being the last time it
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// was used to perform a request
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routes map[uint64]time.Time
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sync.Mutex
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}
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func (r *roundrobin) Init(opts ...selector.Option) error {
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return nil
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}
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func (r *roundrobin) Options() selector.Options {
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return selector.Options{}
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}
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func (r *roundrobin) Select(routes []*router.Route) (*router.Route, error) {
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if len(routes) == 0 {
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return nil, selector.ErrNoneAvailable
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}
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r.Lock()
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defer r.Unlock()
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// setLastUsed will update the last used time for a route
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setLastUsed := func(hash uint64) {
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r.routes[hash] = time.Now()
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}
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// calculate the route hashes once
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hashes := make(map[*router.Route]uint64, len(routes))
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for _, s := range routes {
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hashes[s] = s.Hash()
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}
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// if a route hasn't yet been seen, prioritise it
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for srv, hash := range hashes {
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if _, ok := r.routes[hash]; !ok {
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setLastUsed(hash)
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return srv, nil
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}
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}
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// sort the services by the time they were last used
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sort.SliceStable(routes, func(i, j int) bool {
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iLastSeen := r.routes[hashes[routes[i]]]
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jLastSeen := r.routes[hashes[routes[j]]]
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return iLastSeen.UnixNano() < jLastSeen.UnixNano()
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})
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// return the route which was last used
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setLastUsed(hashes[routes[0]])
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return routes[0], nil
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}
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func (r *roundrobin) Record(srv *router.Route, err error) error {
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return nil
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}
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func (r *roundrobin) Close() error {
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r.ticker.Stop()
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return nil
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}
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func (r *roundrobin) String() string {
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return "roundrobin"
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}
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func (r *roundrobin) cleanRoutes() {
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for {
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// watch for ticks until the ticker is closed
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if _, ok := <-r.ticker.C; !ok {
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return
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}
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r.Lock()
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// copy the slice to prevent concurrent map iteration and map write
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rts := r.routes
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for hash, t := range rts {
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if t.Unix() < time.Now().Add(-routeTTL).Unix() {
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delete(r.routes, hash)
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}
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}
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r.Unlock()
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}
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}
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