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Overview

Use a  Loop Node when it is necessary to repeat an action or set of actions multiple times. 

There are three types of supported looping:

  1. Polling, repeating the same operation multiple times with the same parameters until a desired result is obtained and then generating a single output record. Output results are only generated at the end of the iterations. For example, polling an HTTP API until the results are available.

  2. Accumulation, repeating the same operation multiple times, where each iteration accumulates the progress results and triggers the next iteration with the updated result. Generates a single output record. For example, calling the DB to get the parent record, and repeating with the parent until the root has been reached.

  3. Paging, repeating an operation multiple times with different parameters and generating the next parameters with a set of output records for each iteration of the loop. For example, reading from a paging API, where each iteration gives you the link for the next iteration, and a set of output records.

Start Loop and End Loop

Loops consist of a  Start Loop Actionand an  End Loop Action joined by a loop connector which returns the result of the End Action to the Start Action. Each part of the loop has properties described below.

The key concept of a loop is that the attributes passed into it are available as a passthrough and mapped in attributes. This allows for the original passthrough value to be referenced and if the loop is manipulating the incoming attribute, for example incrementing a number, this is also available. The mapped attributes that are manipulated by the loop are shown with a loop icon, passthrough attributes will be shown with the icon of where they come from for example a calculated action.

 Properties Tab -  Start Loop

Basic Settings

FieldDescriptionExample Value
NameThe name given to the action node and displayed on the canvas.My Loop
End Loop Action

A read-only field that states the end loop action associated with the start loop action.

// The End Loop Action will initially take the name of the Start Loop // Action and prefix it with "end".

End My Loop

Output Connection Points

This section has a toolbar with standard buttonsThe grid contains a list of all output connection points.

  • To add a new output path, in the section toolbar click  Add New to open a new output path and set the expression; see Output Connection Points.
  • To edit an existing output path, double-click it in the list to open its properties.
  • To remove an output path, select one and in the section toolbar click  Delete.

 Properties Tab -  End Loop

Basic Settings

FieldDescriptionExample Value
NameThe name given to the action node and displayed on the canvas. The name will default to the Start Loop name prefixed with end.End My Loop
Output Mode

A read-only field that states the end loop action associated with the start loop action.

// The End Loop Action will initially take the name of the Start Loop // Action and prefix it with "end".

End My Loop

Until ExpressionAn expression that is checked on each cycle of the loop, and once the expression returns true the loop will end.  

// Where myValue is being sent into the End Loop Action on a pipe // called in.

in.myValue == 10

Max LoopsThis is a safety net designed to stop infinite loops. The number entered here will stop 

//Defaults to 10000

10000

Input Connection Points

Can Accept a single  Driving input connection point.

The grid contains a list of all input connection points and their type.

  • To add a new input connection point, in the section toolbar click  Add New to open a new input connection point and set its properties; see Input Connection Points.
  • To edit an existing input connection point, double-click it in the list to open its properties.
  • To remove an input connection point, select one and in the section toolbar click  Delete.

Output Connection Points

This section has a toolbar with standard buttonsThe grid contains a list of all output connection points.

  • To add a new output path, in the section toolbar click  Add New to open a new output path and set the expression; see Output Connection Points.
  • To edit an existing output path, double-click it in the list to open its properties.
  • To remove an output path, select one and in the section toolbar click  Delete.


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