// Unregister returns an error if the service isn't registered in etcd.
func (s *ServiceTest) TestUnregisterUnregisteredService(c *C) {
address := "http://localhost:8080"
routes := switchboard.Routes{"GET": []string{"/users", "/user/:id"}}
service := switchboard.NewService("test", s.client, address, routes)
err := service.Unregister()
c.Assert(err.(*etcd.EtcdError).ErrorCode, Equals, 100)
}
// Register is effectively a no-op if the service record already exists in
// etcd.
func (s *ServiceTest) TestRegisterDuplicate(c *C) {
address := "http://localhost:8080"
routes := switchboard.Routes{"GET": []string{"/users", "/user/:id"}}
service := switchboard.NewService("test", s.client, address, routes)
_, err := service.Register(0)
c.Assert(err, IsNil)
_, err = service.Register(0)
c.Assert(err, IsNil)
}
// Watch observes unregistered services in etcd and removes the relevant
// patterns and addresses from the ExchangeServeMux.
func (s *ExchangeTest) TestWatchUnegisteredService(c *C) {
// Create the namespace in etcd.
_, err := s.client.CreateDir("/test", 0)
c.Assert(err, IsNil)
// Register a new service.
address := "http://localhost:8080"
routes := switchboard.Routes{"GET": []string{"/users"}}
service := switchboard.NewService("test", s.client, address, routes)
_, err = service.Register(0)
c.Assert(err, IsNil)
// Initialize the exchange.
err = s.exchange.Init()
c.Assert(err, IsNil)
// Start the watcher goroutine.
stop := make(chan bool)
stopped := make(chan bool)
go func() {
s.exchange.Watch(stop)
stopped <- true
}()
// Cleanly shutdown the watcher no matter how the test finishes.
defer func() {
stop <- true
c.Assert(<-stopped, Equals, true)
}()
// Unregister the service.
err = service.Unregister()
c.Assert(err, IsNil)
// Janky logic to wait for updates from etcd will fail when updates don't
// propagate within 500ms.
receivedUpdate := false
for i := 0; i < 500; i++ {
addresses, err := s.mux.Match("GET", "/users")
if err == nil {
time.Sleep(time.Duration(1) * time.Millisecond)
continue
} else {
c.Assert(addresses, IsNil)
receivedUpdate = true
break
}
}
c.Assert(receivedUpdate, Equals, true)
}
// Broadcast stops pushing changes to etcd when when a bool value is sent to
// the stop channel.
func (s *ServiceTest) TestBroadcastStops(c *C) {
address := "http://localhost:8080"
routes := switchboard.Routes{"GET": []string{"/users", "/user/:id"}}
service := switchboard.NewService("test", s.client, address, routes)
stop := make(chan bool)
stopped := make(chan bool)
go func() {
service.Broadcast(2, 1, stop)
stopped <- true
}()
stop <- true
c.Assert(<-stopped, Equals, true)
}
// Unregister deletes the service record in etcd.
func (s *ServiceTest) TestUnregister(c *C) {
address := "http://localhost:8080"
routes := switchboard.Routes{"GET": []string{"/users", "/user/:id"}}
service := switchboard.NewService("test", s.client, address, routes)
_, err := service.Register(0)
c.Assert(err, IsNil)
err = service.Unregister()
c.Assert(err, IsNil)
key := "test/" + service.ID()
sort := false
recursive := true
_, err = s.client.Get(key, sort, recursive)
c.Assert(err.(*etcd.EtcdError).ErrorCode, Equals, 100)
}
// Register creates a service record to represent the service and registers it
// in etcd.
func (s *ServiceTest) TestRegister(c *C) {
address := "http://localhost:8080"
routes := switchboard.Routes{"GET": []string{"/users", "/user/:id"}}
service := switchboard.NewService("test", s.client, address, routes)
record, err := service.Register(0)
c.Assert(err, IsNil)
key := "test/" + service.ID()
sort := false
recursive := true
response, err := s.client.Get(key, sort, recursive)
c.Assert(err, IsNil)
recordJSON, _ := json.Marshal(record)
c.Assert(response.Node.Value, Equals, bytes.NewBuffer(recordJSON).String())
}
// Init returns an error if the specified namespace doesn't exist in etcd.
func (s *ExchangeTest) TestInit(c *C) {
address := "http://localhost:8080"
routes := switchboard.Routes{"GET": []string{"/users", "/user/:id"}}
service := switchboard.NewService("test", s.client, address, routes)
_, err := service.Register(0)
c.Assert(err, IsNil)
err = s.exchange.Init()
c.Assert(err, IsNil)
addresses, err := s.mux.Match("GET", "/users")
c.Assert(err, IsNil)
c.Assert(addresses, DeepEquals, &[]string{"http://localhost:8080"})
addresses, err = s.mux.Match("GET", "/user/123")
c.Assert(err, IsNil)
c.Assert(addresses, DeepEquals, &[]string{"http://localhost:8080"})
}
// Broadcast registers a service with etcd.
func (s *ServiceTest) TestBroadcast(c *C) {
// Create a new service.
address := "http://localhost:8080"
routes := switchboard.Routes{"GET": []string{"/users", "/user/:id"}}
service := switchboard.NewService("test", s.client, address, routes)
// Start broadcasting service changes to etcd.
stop := make(chan bool)
stopped := make(chan bool)
go func() {
service.Broadcast(2, 1, stop)
stopped <- true
}()
// Cleanly shutdown the broadcaster no matter how the test finishes.
defer func() {
stop <- true
c.Assert(<-stopped, Equals, true)
}()
// Janky logic to wait for the broadcaster to write a value to etcd that
// can be read back will fail when service registration doesn't complete
// within 500ms.
receivedUpdate := false
for i := 0; i < 500; i++ {
key := "test/" + service.ID()
sort := false
recursive := true
response, err := s.client.Get(key, sort, recursive)
if err != nil {
time.Sleep(time.Duration(1) * time.Millisecond)
continue
} else {
record := switchboard.ServiceRecord{
ID: service.ID(),
Address: service.Address(),
Routes: service.Routes()}
recordJSON, _ := json.Marshal(record)
c.Assert(response.Node.Value, Equals, bytes.NewBuffer(recordJSON).String())
receivedUpdate = true
break
}
}
c.Assert(receivedUpdate, Equals, true)
}
// Watch stops observing changes in etcd when when a bool value is sent to the
// stop channel.
func (s *ExchangeTest) TestWatchStops(c *C) {
address := "http://localhost:8080"
routes := switchboard.Routes{"GET": []string{"/users", "/user/:id"}}
service := switchboard.NewService("test", s.client, address, routes)
_, err := service.Register(0)
c.Assert(err, IsNil)
stop := make(chan bool)
stopped := make(chan bool)
go func() {
err = s.exchange.Init()
c.Assert(err, IsNil)
s.exchange.Watch(stop)
stopped <- true
}()
stop <- true
c.Assert(<-stopped, Equals, true)
}
func main() {
// Setup HTTP routes and initialize the service.
port := os.Getenv("PORT")
address := "http://localhost:" + port
client := etcd.NewClient([]string{"http://127.0.0.1:4001"})
routes := switchboard.Routes{"GET": []string{"/hello/:name"}}
service := switchboard.NewService("example", client, address, routes)
// Broadcast service presence to etcd every 5 seconds (with a TTL of 10
// seconds). If this service crashes the exchange will only attempt to
// route requests to it during the TTL window.
go func() {
log.Print("Broadcasting service configuration to etcd")
stop := make(chan bool)
service.Broadcast(5, 10, stop)
}()
// Unregister the service in etcd when we receive a SIGTERM.
interrupt := make(chan os.Signal, 1)
signal.Notify(interrupt, os.Interrupt)
go func() {
for sig := range interrupt {
log.Print("Unregistering service")
service.Unregister()
log.Fatal(sig)
}
}()
// Setup a handler to process requests for our registered routes and
// listen for HTTP requests from the exchange.
handler := pat.New()
handler.Get("/hello/:name", Log(http.HandlerFunc(Hello)))
log.Printf("Listening for HTTP requests on port %v", port)
err := http.ListenAndServe("localhost:"+port, handler)
if err != nil {
log.Print(err)
log.Print("Unregistering service")
service.Unregister()
log.Print("Shutting down")
}
}
