/
service.go
299 lines (262 loc) · 6.25 KB
/
service.go
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package mqtt
import (
"bytes"
"fmt"
"log"
"sync"
text "text/template"
"github.com/influxdata/kapacitor/alert"
"github.com/influxdata/kapacitor/keyvalue"
"github.com/pkg/errors"
)
type Diagnostic interface {
WithContext(ctx ...keyvalue.T) Diagnostic
Error(msg string, err error)
CreatingAlertHandler(c HandlerConfig)
HandlingEvent()
}
// QoSLevel indicates the quality of service for messages delivered to a
// broker.
type QoSLevel byte
var (
ErrInvalidQoS = errors.New("invalid QoS")
)
func (q *QoSLevel) UnmarshalText(text []byte) error {
switch string(text) {
case "at-most-once":
*q = AtMostOnce
case "at-least-once":
*q = AtLeastOnce
case "exactly-one":
*q = ExactlyOnce
default:
return ErrInvalidQoS
}
return nil
}
func (q QoSLevel) MarshalText() (text []byte, err error) {
switch q {
case AtMostOnce:
return []byte("at-most-once"), nil
case AtLeastOnce:
return []byte("at-least-once"), nil
case ExactlyOnce:
return []byte("exactly-once"), nil
default:
return []byte{}, ErrInvalidQoS
}
}
const (
// best effort delivery. "fire and forget"
AtMostOnce QoSLevel = iota
// guarantees delivery to at least one receiver. May deliver multiple times.
AtLeastOnce
// guarantees delivery only once. Safest and slowest.
ExactlyOnce
)
type Service struct {
diag Diagnostic
bufPool sync.Pool
mu sync.RWMutex
clients map[string]Client
configs map[string]Config
defaultBrokerName string
}
func NewService(cs Configs, d Diagnostic) (*Service, error) {
configs := cs.index()
clients := make(map[string]Client, len(cs))
var defaultBrokerName string
for name, c := range configs {
if c.Enabled {
cli, err := c.NewClient()
if err != nil {
return nil, err
}
clients[name] = cli
}
if c.Default {
defaultBrokerName = c.Name
}
}
if len(cs) == 1 {
defaultBrokerName = cs[0].Name
}
return &Service{
diag: d,
bufPool: sync.Pool{
New: func() interface{} {
return new(bytes.Buffer)
},
},
configs: configs,
clients: clients,
defaultBrokerName: defaultBrokerName,
}, nil
}
func (s *Service) Open() error {
s.mu.Lock()
defer s.mu.Unlock()
for name, client := range s.clients {
if client == nil {
return fmt.Errorf("no client found for MQTT broker %q", name)
}
if err := client.Connect(); err != nil {
return errors.Wrapf(err, "failed to connect to MQTT broker %q", name)
}
}
return nil
}
func (s *Service) Close() error {
s.mu.Lock()
defer s.mu.Unlock()
for _, client := range s.clients {
if client != nil {
client.Disconnect()
}
}
return nil
}
func (s *Service) Alert(brokerName, topic string, qos QoSLevel, retained bool, message string) error {
log.Println("D! ALERT", topic, message)
s.mu.RLock()
defer s.mu.RUnlock()
if topic == "" {
return fmt.Errorf("missing MQTT topic")
}
if brokerName == "" {
brokerName = s.defaultBrokerName
}
client := s.clients[brokerName]
if client == nil {
return fmt.Errorf("unknown MQTT broker %q", brokerName)
}
return client.Publish(topic, qos, retained, []byte(message))
}
func (s *Service) Update(newConfigs []interface{}) error {
cs := make(Configs, len(newConfigs))
for i, c := range newConfigs {
config, ok := c.(Config)
if !ok {
return fmt.Errorf("expected config object to be of type %T, got %T", config, c)
}
cs[i] = config
}
return s.update(cs)
}
func (s *Service) update(cs Configs) error {
s.mu.Lock()
defer s.mu.Unlock()
if err := cs.Validate(); err != nil {
return err
}
configs := cs.index()
for name, c := range configs {
if c.Default {
s.defaultBrokerName = name
}
old, ok := s.configs[name]
if ok && old.Equal(c) {
continue
}
client := s.clients[name]
if client != nil {
client.Disconnect()
}
s.clients[name] = nil
if c.Enabled {
client, err := c.NewClient()
if err != nil {
return err
}
if err := client.Connect(); err != nil {
return err
}
s.clients[name] = client
}
}
if len(cs) == 1 {
s.defaultBrokerName = cs[0].Name
}
// Disconnect and remove old clients
for name := range s.configs {
if _, ok := configs[name]; !ok {
client := s.clients[name]
if client != nil {
client.Disconnect()
}
delete(s.clients, name)
}
}
s.configs = configs
return nil
}
func (s *Service) Handler(c HandlerConfig, ctx ...keyvalue.T) (alert.Handler, error) {
d := s.diag.WithContext(ctx...)
d.CreatingAlertHandler(c)
topicTmpl, err := text.New("topic").Parse(c.Topic)
if err != nil {
return nil, err
}
c.TopicTemplate = topicTmpl
return &handler{
s: s,
c: c,
diag: d,
}, nil
}
type HandlerConfig struct {
BrokerName string `mapstructure:"broker-name"`
Topic string `mapstructure:"topic"`
QoS QoSLevel `mapstructure:"qos"`
Retained bool `mapstructure:"retained"`
TopicTemplate *text.Template `mapstructure:"topic-template"`
}
type handler struct {
s *Service
c HandlerConfig
diag Diagnostic
}
func (h *handler) Handle(event alert.Event) {
h.diag.HandlingEvent()
topic, err := h.renderTopic(h.c.TopicTemplate, event)
if err != nil {
h.diag.Error("failed to create MQTT topic from template", err)
} else if err = h.s.Alert(h.c.BrokerName, topic, h.c.QoS, h.c.Retained, event.State.Message); err != nil {
h.diag.Error("failed to post message to MQTT broker", err)
}
}
func (h *handler) renderTopic(topicTmpl *text.Template, event alert.Event) (string, error) {
td := event.TemplateData()
topicBuf := h.s.bufPool.Get().(*bytes.Buffer)
defer func() {
topicBuf.Reset()
h.s.bufPool.Put(topicBuf)
}()
err := topicTmpl.Execute(topicBuf, td)
if err != nil {
return "", err
}
return topicBuf.String(), nil
}
type testOptions struct {
BrokerName string `json:"broker-name"`
Topic string `json:"topic"`
Message string `json:"message"`
QoS QoSLevel `json:"qos"`
Retained bool `json:"retained"`
}
func (s *Service) TestOptions() interface{} {
s.mu.RLock()
defer s.mu.RUnlock()
return &testOptions{
BrokerName: s.defaultBrokerName,
Message: "test MQTT message",
}
}
func (s *Service) Test(o interface{}) error {
options, ok := o.(*testOptions)
if !ok {
return fmt.Errorf("unexpected options type %T", options)
}
return s.Alert(options.BrokerName, options.Topic, options.QoS, options.Retained, options.Message)
}