Skip to content
View as markdown Ask ChatGPT Ask Claude

Send Message Bus Message#

The Send Message Bus Message task sends a message to a message bus subject. The message is either a notification (fire and forget) or a request that waits for a reply.

Screenshot showing the Send Message Bus Message task with its inputs and outputs.

Details#

Fields Details
Scope Connect IoT
Data Platform
Enterprise Integration
Factory Automation
Workflow Data flow
Control flow
IsProtocol flag

Inputs#

Name Data Type Description
MessageType String Type of message to send: Notification or Request. Overrides the Message Type setting.
Subject String Message bus subject to send the message to. Overrides the Subject setting.
Message Object Message to send. Overrides the Message setting.
Timeout Integer Maximum time, in milliseconds, to wait for a reply. Only available when the message type is Request.
Activate any Activates the task.

Outputs#

Name Data Type Description
Reply Object Reply received for the request. Only available when the message type is Request.
Success Boolean Emits true when the message is sent or, for a request, when the reply arrives.
Error Error Error that occurred during the processing of this task.

Settings#

On the General tab, the Message section has the following settings:

Name Data Type Default Description
Message Type Enum Notification Notification sends the message without waiting for a reply. Request sends the message and waits for a reply.
Subject String Message bus subject to send the message to.
Message Object {} Message to send using the message bus.
Timeout Integer 60000 Maximum time, in milliseconds, to wait for a reply. Only available when the message type is Request.

Behavior#

When activated, the task sends the message to the configured subject. Values received on the inputs take precedence over the settings.

  • With the Notification message type, the task publishes the message and emits true on the Success output. It does not wait for a reply.
  • With the Request message type, the task sends the message and waits for a reply for up to Timeout milliseconds. When the reply arrives, the task emits it on the Reply output and then emits true on the Success output. If no reply arrives in time or the request fails, the task emits the error on the Error output.

Remarks#

To answer a request inside another workflow, subscribe to the subject with the Message Bus Listener task and reply with the Message Bus Reply task.

Text received on Message together with the activation is parsed as JSON: text that is not JSON is sent as {}, and numeric text is sent as a number, which loses the last digits of a 19-digit MES Id.

A MessageType other than Notification or Request sends nothing and emits neither Success nor Error.