/
dynamic.go
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/
dynamic.go
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// Copyright 2019 Samaritan Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package config
// FIXME: mockgen can't handle cycle imports in reflect mode when outside of GOPATH currently,
// so add self_package parameter temporarily. Refer to: https://github.com/golang/mock/issues/310
//go:generate mockgen -package $GOPACKAGE -self_package $REPO_URI/$GOPACKAGE --destination ./mock_dynamic_test.go $REPO_URI/$GOPACKAGE DynamicSource
import (
"context"
"sync"
"time"
"github.com/samaritan-proxy/samaritan/pb/api"
"github.com/samaritan-proxy/samaritan/pb/config/bootstrap"
"github.com/samaritan-proxy/samaritan/pb/config/service"
"google.golang.org/grpc"
"google.golang.org/grpc/keepalive"
)
var _ DynamicSource = new(dynamicSource)
type dependencyHook func(added, removed []*service.Service)
type svcConfigHook func(svcName string, newCfg *service.Config)
type svcEndpointHook func(svcName string, added, removed []*service.Endpoint)
// DynamicSource represents the dynamic config source.
type DynamicSource interface {
// SetDependencyHook sets a hook which will be called
// when a dependency is added or removed. It must be
// called before Serve.
SetDependencyHook(hook dependencyHook)
// SetSvcConfigHook sets a hook which wil be called
// when the proxy config of subscribed service update.
// It must be called before Serve.
SetSvcConfigHook(hook svcConfigHook)
// SetSvcEndpointHook sets a hook which will be called
// when the endpoints of subscribed service updated.
// It must be called before Serve.
SetSvcEndpointHook(hook svcEndpointHook)
// Serve starts observing the config update from remote.
// It will return until Stop is called.
Serve()
// Stop stops observing the config update from remote.
Stop()
}
type dynamicSource struct {
b *bootstrap.Bootstrap
conn *grpc.ClientConn
c *discoveryClient
dependHook dependencyHook
svcCfgHook svcConfigHook
svcEtHook svcEndpointHook
quit chan struct{}
done chan struct{}
}
func newDynamicSource(b *bootstrap.Bootstrap) (*dynamicSource, error) {
d := &dynamicSource{
b: b,
quit: make(chan struct{}),
done: make(chan struct{}),
}
err := d.initDiscoveryClient()
return d, err
}
func (d *dynamicSource) initDiscoveryClient() error {
target := d.b.DynamicSourceConfig.Endpoint
// TODO: support Authentication
options := []grpc.DialOption{
grpc.WithInsecure(),
grpc.WithKeepaliveParams(keepalive.ClientParameters{
Time: time.Second * 30,
Timeout: time.Second * 10,
}),
}
conn, err := grpc.Dial(target, options...)
if err != nil {
return err
}
d.conn = conn
stub := api.NewDiscoveryServiceClient(conn)
d.c = newDiscoveryClient(stub)
return nil
}
func (d *dynamicSource) SetDependencyHook(hook dependencyHook) {
d.dependHook = hook
}
func (d *dynamicSource) SetSvcConfigHook(hook svcConfigHook) {
d.svcCfgHook = hook
}
func (d *dynamicSource) SetSvcEndpointHook(hook svcEndpointHook) {
d.svcEtHook = hook
}
func (d *dynamicSource) Serve() {
var wg sync.WaitGroup
ctx, cancel := context.WithCancel(context.Background())
wg.Add(1)
go func() {
defer wg.Done()
d.c.StreamDependencies(ctx, d.b.Instance, d.dependHook)
}()
wg.Add(1)
go func() {
defer wg.Done()
d.c.StreamSvcConfigs(ctx, d.svcCfgHook)
}()
wg.Add(1)
go func() {
defer wg.Done()
d.c.StreamSvcEndpoints(ctx, d.svcEtHook)
}()
<-d.quit
cancel()
// close grpc client conn
d.conn.Close()
wg.Wait()
close(d.done)
}
func (d *dynamicSource) Stop() {
close(d.quit)
<-d.done
}