/
resolver.go
228 lines (208 loc) · 5.37 KB
/
resolver.go
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package resolver
import (
"context"
"fmt"
"math/rand"
"net/url"
"os"
"sort"
"strconv"
"strings"
"sync"
"github.com/mapgoo-lab/atreus/pkg/conf/env"
"github.com/mapgoo-lab/atreus/pkg/log"
"github.com/mapgoo-lab/atreus/pkg/naming"
wmeta "github.com/mapgoo-lab/atreus/pkg/net/rpc/warden/internal/metadata"
farm "github.com/dgryski/go-farm"
"github.com/pkg/errors"
"google.golang.org/grpc/resolver"
)
const (
// Scheme is the scheme of discovery address
Scheme = "grpc"
)
var (
_ resolver.Resolver = &Resolver{}
_ resolver.Builder = &Builder{}
mu sync.Mutex
)
// Register register resolver builder if nil.
func Register(b naming.Builder) {
mu.Lock()
defer mu.Unlock()
if resolver.Get(b.Scheme()) == nil {
resolver.Register(&Builder{b})
}
}
// Set override any registered builder
func Set(b naming.Builder) {
mu.Lock()
defer mu.Unlock()
resolver.Register(&Builder{b})
}
// Builder is also a resolver builder.
// It's build() function always returns itself.
type Builder struct {
naming.Builder
}
// Build returns itself for Resolver, because it's both a builder and a resolver.
func (b *Builder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOptions) (resolver.Resolver, error) {
var zone = env.Zone
ss := int64(50)
clusters := map[string]struct{}{}
str := strings.SplitN(target.Endpoint, "?", 2)
if len(str) == 0 {
return nil, errors.Errorf("warden resolver: parse target.Endpoint(%s) failed!err:=endpoint is empty", target.Endpoint)
} else if len(str) == 2 {
m, err := url.ParseQuery(str[1])
if err == nil {
for _, c := range m[naming.MetaCluster] {
clusters[c] = struct{}{}
}
zones := m[naming.MetaZone]
if len(zones) > 0 {
zone = zones[0]
}
if sub, ok := m["subset"]; ok {
if t, err := strconv.ParseInt(sub[0], 10, 64); err == nil {
ss = t
}
}
}
}
r := &Resolver{
nr: b.Builder.Build(str[0]),
cc: cc,
quit: make(chan struct{}, 1),
clusters: clusters,
zone: zone,
subsetSize: ss,
}
go r.updateproc()
return r, nil
}
// Resolver watches for the updates on the specified target.
// Updates include address updates and service config updates.
type Resolver struct {
nr naming.Resolver
cc resolver.ClientConn
quit chan struct{}
clusters map[string]struct{}
zone string
subsetSize int64
}
// Close is a noop for Resolver.
func (r *Resolver) Close() {
select {
case r.quit <- struct{}{}:
r.nr.Close()
default:
}
}
// ResolveNow is a noop for Resolver.
func (r *Resolver) ResolveNow(o resolver.ResolveNowOptions) {
}
func (r *Resolver) updateproc() {
event := r.nr.Watch()
for {
select {
case <-r.quit:
return
case _, ok := <-event:
if !ok {
return
}
}
if ins, ok := r.nr.Fetch(context.Background()); ok {
instances, _ := ins.Instances[r.zone]
res := r.filter(instances)
if len(res) == 0 {
for _, value := range ins.Instances {
instances = append(instances, value...)
}
res = r.filter(instances)
}
r.newAddress(res)
}
}
}
func (r *Resolver) filter(backends []*naming.Instance) (instances []*naming.Instance) {
if len(backends) == 0 {
return
}
for _, ins := range backends {
//如果r.clusters的长度大于0说明需要进行集群选择
if _, ok := r.clusters[ins.Metadata[naming.MetaCluster]]; !ok && len(r.clusters) > 0 {
continue
}
var addr string
for _, a := range ins.Addrs {
u, err := url.Parse(a)
if err == nil && u.Scheme == Scheme {
addr = u.Host
}
}
if addr == "" {
fmt.Fprintf(os.Stderr, "resolver: app(%s,%s) no valid grpc address(%v) found!", ins.AppID, ins.Hostname, ins.Addrs)
log.Warn("resolver: invalid rpc address(%s,%s,%v) found!", ins.AppID, ins.Hostname, ins.Addrs)
continue
}
instances = append(instances, ins)
}
if len(instances) == 0 {
for _, bkend := range backends {
log.Warn("resolver: backends(%d) invalid instance:%v", len(backends), bkend)
}
return
}
if r.subsetSize > 0 {
instances = r.subset(instances, env.Hostname, r.subsetSize)
}
return
}
func (r *Resolver) subset(backends []*naming.Instance, clientID string, size int64) []*naming.Instance {
if len(backends) <= int(size) {
return backends
}
sort.Slice(backends, func(i, j int) bool {
return backends[i].Hostname < backends[j].Hostname
})
count := int64(len(backends)) / size
id := farm.Fingerprint64([]byte(clientID))
round := int64(id / uint64(count))
s := rand.NewSource(round)
ra := rand.New(s)
ra.Shuffle(len(backends), func(i, j int) {
backends[i], backends[j] = backends[j], backends[i]
})
start := (id % uint64(count)) * uint64(size)
return backends[int(start) : int(start)+int(size)]
}
func (r *Resolver) newAddress(instances []*naming.Instance) {
if len(instances) <= 0 {
return
}
addrs := make([]resolver.Address, 0, len(instances))
for _, ins := range instances {
var weight int64
if weight, _ = strconv.ParseInt(ins.Metadata[naming.MetaWeight], 10, 64); weight <= 0 {
weight = 10
}
var rpc string
for _, a := range ins.Addrs {
u, err := url.Parse(a)
if err == nil && u.Scheme == Scheme {
rpc = u.Host
}
}
addr := resolver.Address{
Addr: rpc,
Type: resolver.Backend,
ServerName: ins.AppID,
Metadata: wmeta.MD{Weight: uint64(weight), Color: ins.Metadata[naming.MetaColor]},
}
addrs = append(addrs, addr)
}
log.Info("resolver: finally get %d instances", len(addrs))
r.cc.NewAddress(addrs)
}