/
subscriber.go
279 lines (242 loc) · 7.03 KB
/
subscriber.go
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package mbus
import (
"encoding/json"
"errors"
"fmt"
"os"
"strings"
"code.cloudfoundry.org/gorouter/common"
"code.cloudfoundry.org/gorouter/common/uuid"
"code.cloudfoundry.org/gorouter/config"
"code.cloudfoundry.org/gorouter/logger"
"code.cloudfoundry.org/gorouter/registry"
"code.cloudfoundry.org/gorouter/route"
"code.cloudfoundry.org/localip"
"code.cloudfoundry.org/routing-api/models"
"github.com/mailru/easyjson"
"github.com/nats-io/go-nats"
"github.com/uber-go/zap"
)
// RegistryMessage defines the format of a route registration/unregistration
// easyjson:json
type RegistryMessage struct {
Host string `json:"host"`
Port uint16 `json:"port"`
TLSPort uint16 `json:"tls_port"`
Uris []route.Uri `json:"uris"`
Tags map[string]string `json:"tags"`
App string `json:"app"`
StaleThresholdInSeconds int `json:"stale_threshold_in_seconds"`
RouteServiceURL string `json:"route_service_url"`
PrivateInstanceID string `json:"private_instance_id"`
ServerCertDomainSAN string `json:"server_cert_domain_san"`
PrivateInstanceIndex string `json:"private_instance_index"`
IsolationSegment string `json:"isolation_segment"`
}
func (rm *RegistryMessage) makeEndpoint(acceptTLS bool) (*route.Endpoint, error) {
port, useTls, err := rm.port(acceptTLS)
if err != nil {
return nil, err
}
return route.NewEndpoint(
rm.App,
rm.Host,
port,
rm.ServerCertDomainSAN,
rm.PrivateInstanceID,
rm.PrivateInstanceIndex,
rm.Tags,
rm.StaleThresholdInSeconds,
rm.RouteServiceURL,
models.ModificationTag{},
rm.IsolationSegment,
useTls,
), nil
}
// ValidateMessage checks to ensure the registry message is valid
func (rm *RegistryMessage) ValidateMessage() bool {
return rm.RouteServiceURL == "" || strings.HasPrefix(rm.RouteServiceURL, "https")
}
// Prefer TLS Port instead of HTTP Port in Registrty Message
func (rm *RegistryMessage) port(acceptTLS bool) (uint16, bool, error) {
if !acceptTLS && rm.Port == 0 {
return 0, false, errors.New("Invalid registry message: backend tls is not enabled")
} else if acceptTLS && rm.TLSPort != 0 {
return rm.TLSPort, true, nil
}
return rm.Port, false, nil
}
// Subscriber subscribes to NATS for all router.* messages and handles them
type Subscriber struct {
mbusClient Client
routeRegistry registry.Registry
subscription *nats.Subscription
reconnected <-chan Signal
params startMessageParams
acceptTLS bool
logger logger.Logger
}
type startMessageParams struct {
id string
minimumRegisterIntervalInSeconds int
pruneThresholdInSeconds int
}
// NewSubscriber returns a new Subscriber
func NewSubscriber(
mbusClient Client,
routeRegistry registry.Registry,
c *config.Config,
reconnected <-chan Signal,
l logger.Logger,
) *Subscriber {
guid, err := uuid.GenerateUUID()
if err != nil {
l.Fatal("failed-to-generate-uuid", zap.Error(err))
}
return &Subscriber{
mbusClient: mbusClient,
routeRegistry: routeRegistry,
params: startMessageParams{
id: fmt.Sprintf("%d-%s", c.Index, guid),
minimumRegisterIntervalInSeconds: int(c.StartResponseDelayInterval.Seconds()),
pruneThresholdInSeconds: int(c.DropletStaleThreshold.Seconds()),
},
acceptTLS: c.Backends.EnableTLS,
reconnected: reconnected,
logger: l,
}
}
// Run manages the lifecycle of the subscriber process
func (s *Subscriber) Run(signals <-chan os.Signal, ready chan<- struct{}) error {
s.logger.Info("subscriber-starting")
if s.mbusClient == nil {
return errors.New("subscriber: nil mbus client")
}
err := s.sendStartMessage()
if err != nil {
return err
}
err = s.subscribeToGreetMessage()
if err != nil {
return err
}
s.subscription, err = s.subscribeRoutes()
if err != nil {
return err
}
close(ready)
s.logger.Info("subscriber-started")
for {
select {
case <-s.reconnected:
err := s.sendStartMessage()
if err != nil {
s.logger.Error("failed-to-send-start-message", zap.Error(err))
}
case <-signals:
s.logger.Info("exited")
return nil
}
}
}
func (s *Subscriber) Pending() (int, error) {
if s.subscription == nil {
s.logger.Error("failed-to-get-subscription")
return -1, errors.New("NATS subscription is nil, Subscriber must be invoked")
}
msgs, _, err := s.subscription.Pending()
return msgs, err
}
func (s *Subscriber) subscribeToGreetMessage() error {
_, err := s.mbusClient.Subscribe("router.greet", func(msg *nats.Msg) {
response, _ := s.startMessage()
_ = s.mbusClient.Publish(msg.Reply, response)
})
return err
}
func (s *Subscriber) subscribeRoutes() (*nats.Subscription, error) {
natsSubscription, err := s.mbusClient.Subscribe("router.*", func(message *nats.Msg) {
msg, regErr := createRegistryMessage(message.Data)
if regErr != nil {
s.logger.Error("validation-error",
zap.Error(regErr),
zap.String("payload", string(message.Data)),
zap.String("subject", message.Subject),
)
return
}
switch message.Subject {
case "router.register":
s.registerEndpoint(msg)
case "router.unregister":
s.unregisterEndpoint(msg)
s.logger.Info("unregister-route", zap.String("message", string(message.Data)))
default:
}
})
// Pending limits are set to twice the defaults
natsSubscription.SetPendingLimits(131072, 131072*1024)
return natsSubscription, err
}
func (s *Subscriber) registerEndpoint(msg *RegistryMessage) {
endpoint, err := msg.makeEndpoint(s.acceptTLS)
if err != nil {
s.logger.Error("Unable to register route",
zap.Error(err),
zap.Object("message", msg),
)
return
}
for _, uri := range msg.Uris {
s.routeRegistry.Register(uri, endpoint)
}
}
func (s *Subscriber) unregisterEndpoint(msg *RegistryMessage) {
endpoint, err := msg.makeEndpoint(s.acceptTLS)
if err != nil {
s.logger.Error("Unable to unregister route",
zap.Error(err),
zap.Object("message", msg),
)
return
}
for _, uri := range msg.Uris {
s.routeRegistry.Unregister(uri, endpoint)
}
}
func (s *Subscriber) startMessage() ([]byte, error) {
host, err := localip.LocalIP()
if err != nil {
return nil, err
}
d := common.RouterStart{
Id: s.params.id,
Hosts: []string{host},
MinimumRegisterIntervalInSeconds: s.params.minimumRegisterIntervalInSeconds,
PruneThresholdInSeconds: s.params.pruneThresholdInSeconds,
}
message, err := json.Marshal(d)
if err != nil {
return nil, err
}
return message, nil
}
func (s *Subscriber) sendStartMessage() error {
message, err := s.startMessage()
if err != nil {
return err
}
// Send start message once at start
return s.mbusClient.Publish("router.start", message)
}
func createRegistryMessage(data []byte) (*RegistryMessage, error) {
var msg RegistryMessage
jsonErr := easyjson.Unmarshal(data, &msg)
if jsonErr != nil {
return nil, jsonErr
}
if !msg.ValidateMessage() {
return nil, errors.New("Unable to validate message. route_service_url must be https")
}
return &msg, nil
}