go-zeromq

Go bindings for zerosvc

Event field mapping

MQTTv3 format is whole event serialized into JSON AMQP/MQTTv5 uses headers and puts body as-is

event	MQTTv3	MQTTv5 (future)	AMQP
Reply to	body json	UserProperty[reply_to]	Header[reply_to]
Redelivered	DUP transport flag	DUP transport flag	redelivered flag
RetainTill	retain flag (NO TTL)	retain + Expiry	no support
Headers	body JSON	UserProperty	Headers[]
Body	body JSON['body']	Body	Body

• extra transport control headers:

header key	MQTTv3	MQTTv5	AMQP
_transport_ttl	---	Expiry	TTL
node-name	---	retained	AppId
correlation-id	---	retained	CorrelationId
user-id	---	retained	UserId

other:

• topic of incoming messages is encoded in `RoutingKey

MQTT URL options

• username/pass - same as basic auth e.g. tcp://mqttuser:[email protected]:1883
• TLS - just change proto to tls - tls://mqtt.example.com:8883
• query options
  • CA - tls://mqtt.example.com:8883/?ca=/my/ca/path.crt
  • client cert (key + cert in one file) - tls://mqtt.example.com:8883/?cert=/path/certandkey.pem
  • client cert (key, cert in separate file) - tls://mqtt.example.com:8883/?cert=/path/cert.pem&certkey=/path/certkey.pem

Examples

Create node

tr := zerosvc.NewTransport(zerosvc.TransportMQTT,"tcp://127.0.0.1:1883",zerosvc.TransportMQTTConfig{})
	node := zerosvc.NewNode("unique-node-name")
	tr.Connect()
	node.SetTransport(tr)

prepare and send event. Prepare() takes care of checksums/signatures for the event

	e := zerosvc.Event{
		Headers:    map[string]interface{}{
			"test": "header",
		},
		Body:        []byte("hay"),
	}
	e.Prepare()
	node.SendEvent("dpp/ev",e)

Quirks

• Due to how MQTT libraries work only first user/password is used for all urls.