PublishMQTT
Description
Publishes a message to an MQTT topic
Tags
IOT, MQTT, publish
Properties
In the list below required Properties are shown with an asterisk (*). Other properties are considered optional. The table also indicates any default values, and whether a property supports the NiFi Expression Language.
| Display Name | API Name | Default Value | Allowable Values | Description |
|---|---|---|---|---|
| Broker URI * | Broker URI | The URI(s) to use to connect to the MQTT broker (e.g., tcp://localhost:1883). The 'tcp', 'ssl', 'ws' and 'wss' schemes are supported. In order to use 'ssl', the SSL Context Service property must be set. When a comma-separated URI list is set (e.g., tcp://localhost:1883,tcp://localhost:1884), the processor will use a round-robin algorithm to connect to the brokers on connection failure. Supports Expression Language, using Environment variables. | ||
| MQTT Specification Version * | MQTT Specification Version | v3 AUTO |
| The MQTT specification version when connecting with the broker. See the allowable value descriptions for more details. |
| Username | Username | Username to use when connecting to the broker Supports Expression Language, using Environment variables. | ||
| Password | Password | Password to use when connecting to the broker | ||
| SSL Context Service | SSL Context Service | Controller Service: SSLContextService Implementations: StandardRestrictedSSLContextService StandardSSLContextService | The SSL Context Service used to provide client certificate information for TLS/SSL connections. | |
| Session state * | Session state | Clean Session |
| Whether to start a fresh or resume previous flows. See the allowable value descriptions for more details. |
| Session Expiry Interval | Session Expiry Interval | 24 hrs | After this interval the broker will expire the client and clear the session state. This property is only considered if:
| |
| Client ID | Client ID | MQTT client ID to use. If not set, a UUID will be generated. Supports Expression Language, using Environment variables. | ||
| Topic * | Topic | The topic to publish the message to. Supports Expression Language, using FlowFile attributes and Environment variables. | ||
| Retain Message * | Retain Message | Whether or not the retain flag should be set on the MQTT message. Supports Expression Language, using FlowFile attributes and Environment variables. | ||
| Quality of Service (QoS) * | Quality of Service(QoS) | The Quality of Service (QoS) to send the message with. Accepts three values '0', '1' and '2'; '0' for 'at most once', '1' for 'at least once', '2' for 'exactly once'. Expression language is allowed in order to support publishing messages with different QoS but the end value of the property must be either '0', '1' or '2'. Supports Expression Language, using FlowFile attributes and Environment variables. | ||
| Record Reader | record-reader | Controller Service: RecordReaderFactory Implementations: AvroReader CEFReader CSVReader ExcelReader GrokReader JsonPathReader JsonTreeReader ReaderLookup ScriptedReader Syslog5424Reader SyslogReader WindowsEventLogReader XMLReader YamlTreeReader | The Record Reader to use for parsing the incoming FlowFile into Records. | |
| Record Writer | record-writer | Controller Service: RecordSetWriterFactory Implementations: AvroRecordSetWriter CSVRecordSetWriter FreeFormTextRecordSetWriter JsonRecordSetWriter RecordSetWriterLookup ScriptedRecordSetWriter XMLRecordSetWriter | The Record Writer to use for serializing Records before publishing them as an MQTT Message. | |
| Message Demarcator | message-demarcator | With this property, you have an option to publish multiple messages from a single FlowFile. This property allows you to provide a string (interpreted as UTF-8) to use for demarcating apart the FlowFile content. This is an optional property ; if not provided, and if not defining a Record Reader/Writer, each FlowFile will be published as a single message. To enter special character such as 'new line' use CTRL+Enter or Shift+Enter depending on the OS. Supports Expression Language, using Environment variables. | ||
| Connection Timeout (seconds) | Connection Timeout (seconds) | 30 | Maximum time interval the client will wait for the network connection to the MQTT server to be established. The default timeout is 30 seconds. A value of 0 disables timeout processing meaning the client will wait until the network connection is made successfully or fails. | |
| Keep Alive Interval (seconds) | Keep Alive Interval (seconds) | 60 | Defines the maximum time interval between messages sent or received. It enables the client to detect if the server is no longer available, without having to wait for the TCP/IP timeout. The client will ensure that at least one message travels across the network within each keep alive period. In the absence of a data-related message during the time period, the client sends a very small "ping" message, which the server will acknowledge. A value of 0 disables keepalive processing in the client. | |
| Last Will Message | Last Will Message | The message to send as the client's Last Will. | ||
| Last Will Topic * | Last Will Topic | The topic to send the client's Last Will to. This property is only considered if:
| ||
| Last Will Retain * | Last Will Retain | false |
| Whether to retain the client's Last Will. This property is only considered if:
|
| Last Will QoS Level * | Last Will QoS Level | 0 - At most once |
| QoS level to be used when publishing the Last Will Message. This property is only considered if:
|
Dynamic Properties
This component does not support dynamic properties.
Relationships
| Name | Description |
|---|---|
| failure | FlowFiles that failed to send to the destination are transferred to this relationship. |
| success | FlowFiles that are sent successfully to the destination are transferred to this relationship. |
Reads Attributes
This processor does not read attributes.
Writes Attributes
This processor does not write attributes.
State Management
This component does not store state.
Restricted
This component is not restricted.
Input Requirement
This component requires an incoming relationship.
System Resource Considerations
| Scope | Description |
|---|---|
| MEMORY | An instance of this component can cause high usage of this system resource. Multiple instances or high concurrency settings may result a degradation of performance. |