README
¶
Event Bus NSQ
Installation
go get -u github.com/rafaeljesus/nsq-event-bus
Usage
The nsq-event-bus package exposes a interface for emitting and listening events.
Emitter
import "github.com/rafaeljesus/nsq-event-bus"
topic := "events"
emitter, err := bus.NewEmitter(bus.EmitterConfig{
Address: "localhost:4150",
MaxInFlight: 25,
})
e := event{}
if err = emitter.Emit(topic, &e); err != nil {
// handle failure to emit message
}
// emitting messages on a async fashion
if err = emitter.EmitAsync(topic, &e); err != nil {
// handle failure to emit message
}
Listener
import "github.com/rafaeljesus/nsq-event-bus"
if err = bus.On(bus.ListenerConfig{
Topic: "topic",
Channel: "test_on",
HandlerFunc: handler,
HandlerConcurrency: 4,
}); err != nil {
// handle failure to listen a message
}
func handler(message *Message) (reply interface{}, err error) {
e := event{}
if err = message.DecodePayload(&e); err != nil {
message.Finish()
return
}
if message.Attempts > MAX_DELIVERY_ATTEMPTS {
message.Finish()
return
}
err, _ = doWork(&e)
if err != nil {
message.Requeue(BACKOFF_TIME)
return
}
message.Finish()
return
}
Request (Request/Reply)
import "github.com/rafaeljesus/nsq-event-bus"
topic := "user_signup"
emitter, err = bus.NewEmitter(bus.EmitterConfig{})
e := event{Login: "rafa", Password: "ilhabela_is_the_place"}
if err = bus.Request(topic, &e, handler); err != nil {
// handle failure to listen a message
}
func handler(message *Message) (reply interface{}, err error) {
e := event{}
if err = message.DecodePayload(&e); err != nil {
message.Finish()
return
}
reply = &Reply{}
message.Finish()
return
}
Contributing
- Fork it
- Create your feature branch (
git checkout -b my-new-feature) - Commit your changes (
git commit -am 'Add some feature') - Push to the branch (
git push origin my-new-feature) - Create new Pull Request
Badges
GitHub @rafaeljesus · Medium @_jesus_rafael · Twitter @_jesus_rafael
Documentation
¶
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ( // ErrTopicRequired is returned when topic is not passed as parameter. ErrTopicRequired = errors.New("topic is mandatory") // ErrHandlerRequired is returned when handler is not passed as parameter. ErrHandlerRequired = errors.New("handler is mandatory") // ErrChannelRequired is returned when channel is not passed as parameter in bus.ListenerConfig. ErrChannelRequired = errors.New("channel is mandatory") )
Functions ¶
func On ¶
func On(lc ListenerConfig) error
On listen to a message from a specific topic using nsq consumer, returns an error if topic and channel not passed or if an error occurred while creating nsq consumer.
Types ¶
type Breaker ¶
type Breaker struct {
// Interval is the cyclic period of the closed state for CircuitBreaker to clear the internal counts,
// If Interval is 0, CircuitBreaker doesn't clear the internal counts during the closed state.
Interval time.Duration
// Timeout is the period of the open state, after which the state of CircuitBreaker becomes half-open.
// If Timeout is 0, the timeout value of CircuitBreaker is set to 60 seconds.
Timeout time.Duration
// Threshold when a threshold of failures has been reached, future calls to the broker will not run.
// During this state, the circuit breaker will periodically allow the calls to run and, if it is successful,
// will start running the function again. Default value is 5.
Threshold uint32
// OnStateChange is called whenever the state of CircuitBreaker changes.
OnStateChange func(name, from, to string)
}
Breaker carries the configuration for circuit breaker
type Emitter ¶
type Emitter struct {
// contains filtered or unexported fields
}
Emitter is the emitter wrapper over nsq.
func NewEmitter ¶
func NewEmitter(ec EmitterConfig) (*Emitter, error)
NewEmitter returns a new Emitter configured with the variables from the config parameter, or returning an non-nil err if an error occurred while creating nsq producer.
func (*Emitter) Emit ¶
Emit emits a message to a specific topic using nsq producer, returning an error if encoding payload fails or if an error occurred while publishing the message.
func (*Emitter) EmitAsync ¶
EmitAsync emits a message to a specific topic using nsq producer, but does not wait for the response from `nsqd`. Returns an error if encoding payload fails and logs to console if an error occurred while publishing the message.
func (*Emitter) Request ¶
func (e *Emitter) Request(topic string, payload interface{}, handler HandlerFunc) error
Request a RPC like method which implements request/reply pattern using nsq producer and consumer. Returns an non-nil err if an error occurred while creating or listening to the internal reply topic or encoding the message payload fails or while publishing the message.
type EmitterConfig ¶
type EmitterConfig struct {
Address string
DialTimeout time.Duration
ReadTimeout time.Duration
WriteTimeout time.Duration
LocalAddr net.Addr
LookupdPollInterval time.Duration
LookupdPollJitter float64
MaxRequeueDelay time.Duration
DefaultRequeueDelay time.Duration
BackoffStrategy nsq.BackoffStrategy
MaxBackoffDuration time.Duration
BackoffMultiplier time.Duration
MaxAttempts uint16
LowRdyIdleTimeout time.Duration
RDYRedistributeInterval time.Duration
ClientID string
Hostname string
UserAgent string
HeartbeatInterval time.Duration
SampleRate int32
TLSV1 bool
TLSConfig *tls.Config
Deflate bool
DeflateLevel int
Snappy bool
OutputBufferSize int64
OutputBufferTimeout time.Duration
MaxInFlight int
MsgTimeout time.Duration
AuthSecret string
// Breaker circuit breaker configuration
Breaker
}
EmitterConfig carries the different variables to tune a newly started emitter, it exposes the same configuration available from official nsq go client.
type HandlerFunc ¶
HandlerFunc is the handler function to handle the massage.
type ListenerConfig ¶
type ListenerConfig struct {
Topic string
Channel string
Lookup []string
HandlerFunc HandlerFunc
HandlerConcurrency int
DialTimeout time.Duration
ReadTimeout time.Duration
WriteTimeout time.Duration
LocalAddr net.Addr
LookupdPollInterval time.Duration
LookupdPollJitter float64
MaxRequeueDelay time.Duration
DefaultRequeueDelay time.Duration
BackoffStrategy nsq.BackoffStrategy
MaxBackoffDuration time.Duration
BackoffMultiplier time.Duration
MaxAttempts uint16
LowRdyIdleTimeout time.Duration
RDYRedistributeInterval time.Duration
ClientID string
Hostname string
UserAgent string
HeartbeatInterval time.Duration
SampleRate int32
TLSV1 bool
TLSConfig *tls.Config
Deflate bool
DeflateLevel int
Snappy bool
OutputBufferSize int64
OutputBufferTimeout time.Duration
MaxInFlight int
MsgTimeout time.Duration
AuthSecret string
}
ListenerConfig carries the different variables to tune a newly started consumer, it exposes the same configuration available from official nsq go client.
type Message ¶
type Message struct {
*nsq.Message
ReplyTo string `json:"replyTo"`
Payload []byte `json:"payload"`
Topic string `json:"-"`
}
Message carries nsq.Message fields and methods and adds extra fields for handling messages internally.
func NewMessage ¶
NewMessage returns a new bus.Message.
func (*Message) DecodePayload ¶
DecodePayload deserializes data (as []byte) and creates a new struct passed by parameter.
Source Files