What is the "Flow Val Listener" for and how is it used?

[Can Althaus]

On the Flow engine context is a baseline related List called Flow Val Listeners.

It relates to a table sys_flow_val_listener.

The table itself is empty and I can't make any sense of what records to add here.

It sounds like you could listen to values changing within the flow - which would be super helpful!

Where can I find information on what this is and how to use it? Only release notes stating it has been added, without any explanations.

I can't find anything about it via Google, and even ChatGPT has no answers. 😞 

[Community Alums · Accepted solution]

Hello @Can Althaus ,

A. Purpose of sys_flow_context:

1. The sys_flow_context table in ServiceNow is used to store the context of a flow execution. The context of a flow execution includes information such as the current state of the flow, the values of variables, and the results of actions.
2. The sys_flow_context table is used by the Flow engine to track the progress of a flow execution. The Flow engine updates the sys_flow_context table as the flow executes, recording the current state of the flow, the values of variables, and the results of actions. 
3. The sys_flow_context table can also be used by developers to access the context of a flow execution. For example, a developer can use the sys_flow_context table to get the value of a variable or to get the results of an action.

B. Purpose of sys_flow_val_listener:

1. The sys_flow_val_listener table in ServiceNow is used to store the values of variables that are used in flows. When a flow is executed, the values of the variables in the sys_flow_val_listener table are used to initialize the variables in the flow.
2. The sys_flow_val_listener table is used by the Flow engine to initialize the values of variables in flows. When a flow is executed, the Flow engine queries the sys_flow_val_listener table for the values of the variables that are used in the flow. The Flow engine then uses these values to initialize the variables in the flow.
3. For example, if a flow has a variable named user_id, the Flow engine will query the sys_flow_val_listener table for the value of the user_id variable. If the sys_flow_val_listener table contains a record with the var_name column set to user_id and the var_value column set to the ID of the current user, then the Flow engine will use this value to initialize the user_id variable in the flow.

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regards,

Prasad