

API Docs - v3.0.1

Tested Siddhi Core version: 5.1.13

It could also support other Siddhi Core minor versions.

Sink

mqtt (Sink)

The MQTT sink publishes the events to an MQTT broker

Syntax

@sink(type="mqtt", url="<STRING>", username="<STRING>", password="<STRING>", client.id="<STRING>", topic="<STRING>", quality.of.service="<STRING>", clean.session="<BOOL>", message.retain="<STRING>", keep.alive="<INT>", connection.timeout="<INT>", @map(...)))

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
url	The URL of the MQTT broker. It is used to connect to the MQTT broker It is required to specify a valid URL here.		STRING	No	No
username	The username to be provided when the MQTT client is authenticated by the broker.	null	STRING	Yes	No
password	The password to be provided when the MQTT client is authenticated by the broker.	empty	STRING	Yes	No
client.id	A unique ID for the MQTT client. The server uses this to identify the client when it reconnects. If you do not specify a client ID, the system automatically generates it.	generated by the system	STRING	Yes	No
topic	The topic to which the events processed by WSO2 SP are published via MQTT. This is a mandatory parameter.		STRING	No	Yes
quality.of.service	The quality of service provided by the MQTT client. The possible values are as follows.`0`: The MQTT client sends each event only once. It does not receive an acknowledgement when an event is delivered, and the events are not stored. Events may get lost if the MQTT client is disconnected or if the server fails. This is the fastest method in which events are received via MQTT.`1`: The MQTT client sends each event at least once. If the MQTT client does not receive an acknowledgement to indicate that the event is delivered, it sends the event again.`2`: The MQTT client sends each event only once. The events are stored until the WSO2 SP receives them. This is the safest, but the slowest method of receiving events via MQTT.	1	STRING	Yes	Yes
clean.session	This is an optional paramater. If this parameter is set to `true`, the subscriptions made by the MQTT client during a session expire when the session ends,and they need to be recreated for the next session. If this parameter is set to `false`, all the information relating to the MQTT client's connection to the broker (e.g., the specific topics to which the client has subscribed) are saved after a session. Thus, when a session ends and restarts, the connection is re-established with the same information. The default value is `true`.	true	BOOL	Yes	No
message.retain	If this parameter is set to true, the last message sent from the topic to which WSO2 SP publishes events is retained until the next message is sent.	false	STRING	Yes	Yes
keep.alive	The maximum number of seconds the connection between the MQTT client and the broker should be maintained without any events being transferred. Once this time interval elapses without any event transfers, the connection is dropped. The default value is 60.	60	INT	Yes	No
connection.timeout	The maximum number of seconds that the MQTT client should spend attempting to connect to the MQTT broker. Once this time interval elapses, a timeout takes place.	30	INT	Yes	No

Examples EXAMPLE 1

@sink(type='mqtt', url= 'tcp://localhost:1883', topic='mqtt_topic', clean.session='true', message.retain='false', quality.of.service= '1', keep.alive= '60',connection.timeout='30'@map(type='xml'))Define stream BarStream (symbol string, price float, volume long);

This query publishes events to a stream named BarStream via the MQTT transport. The events are published to a topic named mqtt_topic located at tcp://localhost:1883.

Source

mqtt (Source)

The MQTT source receives the events from an MQTT broker

Syntax

@source(type="mqtt", url="<STRING>", username="<STRING>", password="<STRING>", client.id="<STRING>", topic="<STRING>", quality.of.service="<STRING>", clean.session="<BOOL>", keep.alive="<INT>", connection.timeout="<INT>", @map(...)))

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
url	The URL of the MQTT broker. It is used to connect to the MQTT broker. It is required to specify a valid URL here.		STRING	No	No
username	The username to be provided when the MQTT client is authenticated by the broker.	null	STRING	Yes	No
password	The password to be provided when the MQTT client is authenticated by the broker.	empty	STRING	Yes	No
client.id	A unique ID for the MQTT client. The server uses this to identify the client when it reconnects. If you do not specify a client ID, the system automatically generates it.		STRING	No	No
topic	The topic from which WSO2 SP receives events via MQTT. Multiple topics can be specified as a list of comma separated values.This is a mandatory parameter.		STRING	No	No
quality.of.service	The quality of service provided by the MQTT client. The possible values are as follows.`0`: The MQTT client sends each event to WSO2 SP only once. It does not receive an acknowledgement when an event is delivered, and the events are not stored.Events may get lost if the MQTT client is disconnected or if the server fails.This is the fastest method in which events are received via MQTT.`1`: The MQTT client sends each event to WSO2 SP at least once. If the MQTT client does not receive an acknowledgement to indicate that the event is delivered, it sends the event again.`2`: The MQTT client sends each event to WSO2 SP only once. The events are stored until the WSO2 SP receives them. This is the safest, but the slowest method of receiving events via MQTT.	1	STRING	Yes	No
clean.session	This is an optional paramater. If this parameter is set to `true`, the subscriptions made by the MQTT client during a session expire when the session ends,and they need to be recreated for the next session. If this parameter is set to `false`, all the information relating to the MQTT client's connection to the broker (e.g., the specific topics to which the client has subscribed) are saved after a session. Thus, when a session ends and restarts, the connection is re-established with the same information. The default value is `true`.	true	BOOL	Yes	No
keep.alive	The maximum number of seconds the connection between the MQTT client and the broker should be maintained without any events being transferred. Once this time interval elapses without any event transfers, the connection is dropped. The default value is 60.	60	INT	Yes	No
connection.timeout	The maximum number of seconds that the MQTT client should spend attempting to connect to the MQTT broker. Once this time interval elapses, a timeout takes place.	30	INT	Yes	No

Examples EXAMPLE 1

@source(type='mqtt', url= 'tcp://localhost:1883', topic='mqtt_topic', clean.session='true',quality.of.service= '1', keep.alive= '60',connection.timeout='30'@map(type='xml'))Define stream BarStream (symbol string, price float, volume long);

This query receives events from the mqtt_topic topic via MQTT,and processes them to the BarStream stream.