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go-micro/network/router/service/service.go

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package service
import (
"context"
"errors"
"fmt"
"io"
"sync"
"time"
"github.com/google/uuid"
"github.com/micro/go-micro/client"
"github.com/micro/go-micro/network/router"
pb "github.com/micro/go-micro/network/router/proto"
)
var (
// ErrNotImplemented means the functionality has not been implemented
ErrNotImplemented = errors.New("not implemented")
)
type svc struct {
opts router.Options
router pb.RouterService
status router.Status
watchers map[string]*svcWatcher
exit chan struct{}
errChan chan error
advertChan chan *router.Advert
wg *sync.WaitGroup
sync.RWMutex
}
// NewRouter creates new service router and returns it
func NewRouter(opts ...router.Option) router.Router {
// get default options
options := router.DefaultOptions()
// apply requested options
for _, o := range opts {
o(&options)
}
// NOTE: might need some client opts here
client := client.DefaultClient
// NOTE: should we have Client/Service option in router.Options?
s := &svc{
opts: options,
router: pb.NewRouterService(router.DefaultName, client),
status: router.Status{Code: router.Stopped, Error: nil},
watchers: make(map[string]*svcWatcher),
wg: &sync.WaitGroup{},
}
go s.run()
return s
}
// Init initializes router with given options
func (s *svc) Init(opts ...router.Option) error {
for _, o := range opts {
o(&s.opts)
}
return nil
}
// Options returns router options
func (s *svc) Options() router.Options {
return s.opts
}
// watchErrors watches router errors and takes appropriate actions
func (s *svc) watchErrors() {
var err error
select {
case <-s.exit:
case err = <-s.errChan:
}
s.Lock()
defer s.Unlock()
if s.status.Code != router.Stopped {
// notify all goroutines to finish
close(s.exit)
// TODO" might need to drain some channels here
}
if err != nil {
s.status = router.Status{Code: router.Error, Error: err}
}
}
// watchRouter watches router and send events to all registered watchers
func (s *svc) watchRouter(stream pb.Router_WatchService) error {
defer stream.Close()
var watchErr error
for {
resp, err := stream.Recv()
if err != nil {
if err != io.EOF {
watchErr = err
}
break
}
route := router.Route{
Service: resp.Route.Service,
Address: resp.Route.Address,
Gateway: resp.Route.Gateway,
Network: resp.Route.Network,
Link: resp.Route.Link,
Metric: int(resp.Route.Metric),
}
event := &router.Event{
Type: router.EventType(resp.Type),
Timestamp: time.Unix(0, resp.Timestamp),
Route: route,
}
s.RLock()
for _, w := range s.watchers {
select {
case w.resChan <- event:
case <-w.done:
}
}
s.RUnlock()
}
return watchErr
}
// Run runs the router.
// It returns error if the router is already running.
func (s *svc) run() {
s.Lock()
defer s.Unlock()
switch s.status.Code {
case router.Stopped, router.Error:
stream, err := s.router.Watch(context.Background(), &pb.WatchRequest{})
if err != nil {
s.status = router.Status{Code: router.Error, Error: fmt.Errorf("failed getting router stream: %s", err)}
return
}
// create error and exit channels
s.errChan = make(chan error, 1)
s.exit = make(chan struct{})
s.wg.Add(1)
go func() {
defer s.wg.Done()
select {
case s.errChan <- s.watchRouter(stream):
case <-s.exit:
}
}()
// watch for errors and cleanup
s.wg.Add(1)
go func() {
defer s.wg.Done()
s.watchErrors()
}()
// mark router as Running and set its Error to nil
s.status = router.Status{Code: router.Running, Error: nil}
return
}
return
}
func (s *svc) advertiseEvents(stream pb.Router_AdvertiseService) error {
defer stream.Close()
var advErr error
for {
resp, err := stream.Recv()
if err != nil {
if err != io.EOF {
advErr = err
}
break
}
events := make([]*router.Event, len(resp.Events))
for i, event := range resp.Events {
route := router.Route{
Service: event.Route.Service,
Address: event.Route.Address,
Gateway: event.Route.Gateway,
Network: event.Route.Network,
Link: event.Route.Link,
Metric: int(event.Route.Metric),
}
events[i] = &router.Event{
Type: router.EventType(event.Type),
Timestamp: time.Unix(0, event.Timestamp),
Route: route,
}
}
advert := &router.Advert{
Id: resp.Id,
Type: router.AdvertType(resp.Type),
Timestamp: time.Unix(0, resp.Timestamp),
TTL: time.Duration(resp.Ttl),
Events: events,
}
select {
case s.advertChan <- advert:
case <-s.exit:
return nil
}
}
return advErr
}
// Advertise advertises routes to the network
func (s *svc) Advertise() (<-chan *router.Advert, error) {
s.Lock()
defer s.Unlock()
switch s.status.Code {
case router.Advertising:
return s.advertChan, nil
case router.Running:
stream, err := s.router.Advertise(context.Background(), &pb.AdvertiseRequest{})
if err != nil {
return nil, fmt.Errorf("failed getting advert stream: %s", err)
}
// create advertise and event channels
s.advertChan = make(chan *router.Advert)
s.wg.Add(1)
go func() {
defer s.wg.Done()
select {
case s.errChan <- s.advertiseEvents(stream):
case <-s.exit:
}
}()
// mark router as Running and set its Error to nil
s.status = router.Status{Code: router.Advertising, Error: nil}
return s.advertChan, nil
case router.Stopped:
return nil, fmt.Errorf("not running")
}
return nil, fmt.Errorf("error: %s", s.status.Error)
}
// Process processes incoming adverts
func (s *svc) Process(advert *router.Advert) error {
var events []*pb.Event
for _, event := range advert.Events {
route := &pb.Route{
Service: event.Route.Service,
Address: event.Route.Address,
Gateway: event.Route.Gateway,
Network: event.Route.Network,
Link: event.Route.Link,
Metric: int64(event.Route.Metric),
}
e := &pb.Event{
Type: pb.EventType(event.Type),
Timestamp: event.Timestamp.UnixNano(),
Route: route,
}
events = append(events, e)
}
advertReq := &pb.Advert{
Id: s.Options().Id,
Type: pb.AdvertType(advert.Type),
Timestamp: advert.Timestamp.UnixNano(),
Events: events,
}
if _, err := s.router.Process(context.Background(), advertReq); err != nil {
return err
}
return nil
}
// Create new route in the routing table
func (s *svc) Create(r router.Route) error {
route := &pb.Route{
Service: r.Service,
Address: r.Address,
Gateway: r.Gateway,
Network: r.Network,
Link: r.Link,
Metric: int64(r.Metric),
}
if _, err := s.router.Create(context.Background(), route); err != nil {
return err
}
return nil
}
// Delete deletes existing route from the routing table
func (s *svc) Delete(r router.Route) error {
route := &pb.Route{
Service: r.Service,
Address: r.Address,
Gateway: r.Gateway,
Network: r.Network,
Link: r.Link,
Metric: int64(r.Metric),
}
if _, err := s.router.Delete(context.Background(), route); err != nil {
return err
}
return nil
}
// Update updates route in the routing table
func (s *svc) Update(r router.Route) error {
route := &pb.Route{
Service: r.Service,
Address: r.Address,
Gateway: r.Gateway,
Network: r.Network,
Link: r.Link,
Metric: int64(r.Metric),
}
if _, err := s.router.Update(context.Background(), route); err != nil {
return err
}
return nil
}
// List returns the list of all routes in the table
func (s *svc) List() ([]router.Route, error) {
resp, err := s.router.List(context.Background(), &pb.ListRequest{})
if err != nil {
return nil, err
}
routes := make([]router.Route, len(resp.Routes))
for i, route := range resp.Routes {
routes[i] = router.Route{
Service: route.Service,
Address: route.Address,
Gateway: route.Gateway,
Network: route.Network,
Link: route.Link,
Metric: int(route.Metric),
}
}
return routes, nil
}
// Lookup looks up routes in the routing table and returns them
func (s *svc) Lookup(q router.Query) ([]router.Route, error) {
// call the router
resp, err := s.router.Lookup(context.Background(), &pb.LookupRequest{
Query: &pb.Query{
Service: q.Options().Service,
Gateway: q.Options().Gateway,
Network: q.Options().Network,
},
})
// errored out
if err != nil {
return nil, err
}
routes := make([]router.Route, len(resp.Routes))
for i, route := range resp.Routes {
routes[i] = router.Route{
Service: route.Service,
Address: route.Address,
Gateway: route.Gateway,
Network: route.Network,
Link: route.Link,
Metric: int(route.Metric),
}
}
return routes, nil
}
// Watch returns a watcher which allows to track updates to the routing table
func (s *svc) Watch(opts ...router.WatchOption) (router.Watcher, error) {
wopts := router.WatchOptions{
Service: "*",
}
for _, o := range opts {
o(&wopts)
}
w := &svcWatcher{
opts: wopts,
resChan: make(chan *router.Event, 10),
done: make(chan struct{}),
}
s.Lock()
s.watchers[uuid.New().String()] = w
s.Unlock()
return w, nil
}
// Status returns router status
func (s *svc) Status() router.Status {
s.RLock()
defer s.RUnlock()
// make a copy of the status
status := s.status
return status
}
// Stop stops the router
func (s *svc) Stop() error {
s.Lock()
// only close the channel if the router is running and/or advertising
if s.status.Code == router.Running || s.status.Code == router.Advertising {
// notify all goroutines to finish
close(s.exit)
// TODO: might need to drain some channels here
// mark the router as Stopped and set its Error to nil
s.status = router.Status{Code: router.Stopped, Error: nil}
}
s.Unlock()
// wait for all goroutines to finish
s.wg.Wait()
return nil
}
// Returns the router implementation
func (s *svc) String() string {
return "service"
}