/
consul.go
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/
consul.go
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package consul
import (
"context"
"fmt"
"time"
"github.com/bep/debounce"
"github.com/bhoriuchi/opa-bundle-server/core/clients/consul"
"github.com/bhoriuchi/opa-bundle-server/core/logger"
"github.com/bhoriuchi/opa-bundle-server/core/utils"
"github.com/bhoriuchi/opa-bundle-server/plugins/subscriber"
"github.com/hashicorp/consul/api/watch"
)
const (
ProviderName = "consul"
DefaultDebounce = "200ms"
)
func init() {
subscriber.Providers[ProviderName] = NewSubscriber
}
type Subscriber struct {
name string
wp *watch.Plan
cb func()
client *consul.Client
config *Config
logger logger.Logger
debounce func(f func())
}
type Config struct {
WatchType string `json:"watch_type" yaml:"watch_type"`
Topic string `json:"topic" yaml:"topic"`
Debounce string `json:"debounce" yaml:"debounce"`
Consul *consul.Config `json:"consul" yaml:"consul"`
}
// NewSubscriber creates a new subscriber
func NewSubscriber(opts *subscriber.Options) (subscriber.Subscriber, error) {
s := &Subscriber{
name: opts.Name,
config: &Config{},
cb: opts.Callback,
logger: opts.Logger,
}
if opts.Config == nil {
return nil, fmt.Errorf("invalid configuration for subscriber %s", opts.Name)
}
if err := utils.ReMarshal(opts.Config, s.config); err != nil {
return nil, err
}
if s.config.Debounce == "" {
s.config.Debounce = DefaultDebounce
}
duration, err := time.ParseDuration(s.config.Debounce)
if err != nil {
return nil, fmt.Errorf("invalid debounce duration for consul subscriber %s: %s", s.name, err)
}
s.debounce = debounce.New(duration)
if s.config.Consul == nil {
return nil, fmt.Errorf("no consul configuration provided for subscriber %s", opts.Name)
}
if s.config.Topic == "" {
return nil, fmt.Errorf("no topic specified for consul subscriber %s", s.name)
}
return s, nil
}
func (s *Subscriber) Connect(ctx context.Context) (err error) {
s.logger.Debug("connecting to consul watcher %s at %s", s.name, s.config.Consul.Address)
if s.client != nil {
return fmt.Errorf("already connected")
}
s.client, err = consul.NewClient(s.config.Consul)
if err != nil {
return
}
return
}
func (s *Subscriber) Disconnect(ctx context.Context) (err error) {
if s.client == nil {
err = fmt.Errorf("not connected")
return
}
s.Unsubscribe(ctx)
s.client = nil
return
}
func (s *Subscriber) Subscribe(ctx context.Context) (err error) {
if s.wp != nil {
err = fmt.Errorf("consul watcher already started on subscriber %s", s.name)
return
}
if s.config.Topic == "" {
err = fmt.Errorf("no topic specified for consul subscriber %s", s.name)
return
}
params := map[string]interface{}{
"type": s.config.WatchType,
}
// generate params
switch s.config.WatchType {
case "key":
params["key"] = s.config.Topic
case "keyprefix", "":
params["type"] = "keyprefix"
params["prefix"] = s.config.Topic
case "event":
params["name"] = s.config.Topic
default:
err = fmt.Errorf("unsupported watch type %q for consul subscriber %s", s.config.WatchType, s.name)
return
}
if s.wp, err = watch.Parse(params); err != nil {
return
}
s.wp.HybridHandler = func(bv watch.BlockingParamVal, data interface{}) {
s.logger.Debug("consul subscriber %s received a message", s.name)
s.debounce(s.cb)
}
go func() {
s.logger.Debug("consul subscriber %s is watching prefix %s", s.name, s.config.Topic)
if err := s.wp.RunWithClientAndHclog(s.client.Consul(), s.wp.Logger); err != nil {
s.logger.Error("consul watcher on subscriber %s failed: %s", s.name, err)
}
}()
return
}
func (s *Subscriber) Unsubscribe(ctx context.Context) (err error) {
if s.wp == nil || s.wp.IsStopped() {
err = fmt.Errorf("consul watcher on subscriber %s is already stopped", s.name)
return
}
s.wp.Stop()
s.wp = nil
return
}