/
resolver.go
169 lines (153 loc) · 3.67 KB
/
resolver.go
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package resolver
import (
"fmt"
"net/url"
"os"
"strconv"
"strings"
"github.com/bilibili/discovery/naming"
log "github.com/go-kratos/kratos/pkg/log"
"google.golang.org/grpc/resolver"
)
const (
// Scheme is the scheme of discovery address
Scheme = "grpc"
)
var (
_ resolver.Resolver = &Resolver{}
_ resolver.Builder = &Builder{}
)
// MD is context metadata for balancer and resolver.
type MD struct {
Weight int64
Color string
}
// Register register resolver builder if nil.
func Register(b naming.Builder) {
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) {
// discovery://default/service.name?zone=sh001&cluster=c1&cluster=c2&cluster=c3
dsn := strings.SplitN(target.Endpoint, "?", 2)
if len(dsn) == 0 {
return nil, fmt.Errorf("grpc resolver: parse target.Endpoint(%s) failed! the endpoint is empty", target.Endpoint)
}
// parse params info
zone := os.Getenv("ZONE")
clusters := map[string]struct{}{}
if len(dsn) == 2 {
if u, err := url.ParseQuery(dsn[1]); err == nil {
if zones := u[naming.MetaZone]; len(zones) > 0 {
zone = zones[0]
}
for _, c := range u[naming.MetaCluster] {
clusters[c] = struct{}{}
}
}
}
r := &Resolver{
cc: cc,
nr: b.Builder.Build(dsn[0]),
quit: make(chan struct{}, 1),
zone: zone,
clusters: clusters,
}
go r.watcher()
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{}
zone string
clusters map[string]struct{}
}
// 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) watcher() {
event := r.nr.Watch()
for {
select {
case <-r.quit:
return
case _, ok := <-event:
if !ok {
return
}
}
ins, ok := r.nr.Fetch()
if ok {
instances, ok := ins.Instances[r.zone]
if !ok {
for _, value := range ins.Instances {
instances = append(instances, value...)
}
}
if len(instances) > 0 {
r.newAddress(instances)
}
}
}
}
func (r *Resolver) newAddress(instances []*naming.Instance) {
var (
totalWeight int64
addrs = make([]resolver.Address, 0, len(instances))
)
for n, ins := range instances {
if len(r.clusters) > 0 {
if _, ok := r.clusters[ins.Metadata[naming.MetaCluster]]; !ok {
continue
}
}
rpcAddr, color, weight := extractAddrs(ins)
if rpcAddr == "" {
log.Warn("grpc resolver: invalid rpc address(%s,%s,%v) found!", ins.AppID, ins.Hostname, ins.Addrs)
continue
}
if weight <= 0 {
if totalWeight == 0 {
weight = 10
} else {
weight = totalWeight / int64(n)
}
}
totalWeight += weight
addr := resolver.Address{
Addr: rpcAddr,
Type: resolver.Backend,
ServerName: ins.AppID,
Metadata: &MD{Weight: weight, Color: color},
}
addrs = append(addrs, addr)
}
r.cc.NewAddress(addrs)
}
func extractAddrs(ins *naming.Instance) (addr, color string, weight int64) {
color = ins.Metadata[naming.MetaColor]
weight, _ = strconv.ParseInt(ins.Metadata[naming.MetaWeight], 10, 64)
for _, a := range ins.Addrs {
u, err := url.Parse(a)
if err == nil && u.Scheme == Scheme {
addr = u.Host
}
}
return
}