forked from go-kratos/kratos
/
resolver.go
104 lines (94 loc) · 2.28 KB
/
resolver.go
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package discovery
import (
"context"
"encoding/json"
"errors"
"time"
"github.com/SeeMusic/kratos/v2/internal/endpoint"
"github.com/SeeMusic/kratos/v2/log"
"github.com/SeeMusic/kratos/v2/registry"
"google.golang.org/grpc/attributes"
"google.golang.org/grpc/resolver"
)
type discoveryResolver struct {
w registry.Watcher
cc resolver.ClientConn
log *log.Helper
ctx context.Context
cancel context.CancelFunc
insecure bool
}
func (r *discoveryResolver) watch() {
for {
select {
case <-r.ctx.Done():
return
default:
}
ins, err := r.w.Next()
if err != nil {
if errors.Is(err, context.Canceled) {
return
}
r.log.Errorf("[resolver] Failed to watch discovery endpoint: %v", err)
time.Sleep(time.Second)
continue
}
r.update(ins)
}
}
func (r *discoveryResolver) update(ins []*registry.ServiceInstance) {
addrs := make([]resolver.Address, 0)
endpoints := make(map[string]struct{})
for _, in := range ins {
endpoint, err := endpoint.ParseEndpoint(in.Endpoints, "grpc", !r.insecure)
if err != nil {
r.log.Errorf("[resolver] Failed to parse discovery endpoint: %v", err)
continue
}
if endpoint == "" {
continue
}
// filter redundant endpoints
if _, ok := endpoints[endpoint]; ok {
continue
}
endpoints[endpoint] = struct{}{}
addr := resolver.Address{
ServerName: in.Name,
Attributes: parseAttributes(in.Metadata),
Addr: endpoint,
}
addr.Attributes = addr.Attributes.WithValue("rawServiceInstance", in)
addrs = append(addrs, addr)
}
if len(addrs) == 0 {
r.log.Warnf("[resolver] Zero endpoint found,refused to write, instances: %v", ins)
return
}
err := r.cc.UpdateState(resolver.State{Addresses: addrs})
if err != nil {
r.log.Errorf("[resolver] failed to update state: %s", err)
}
b, _ := json.Marshal(ins)
r.log.Infof("[resolver] update instances: %s", b)
}
func (r *discoveryResolver) Close() {
r.cancel()
err := r.w.Stop()
if err != nil {
r.log.Errorf("[resolver] failed to watch top: %s", err)
}
}
func (r *discoveryResolver) ResolveNow(options resolver.ResolveNowOptions) {}
func parseAttributes(md map[string]string) *attributes.Attributes {
var a *attributes.Attributes
for k, v := range md {
if a == nil {
a = attributes.New(k, v)
} else {
a = a.WithValue(k, v)
}
}
return a
}