Loop Nodes
- Anthony George
- Zoe Baldwin
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:
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.
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.
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.
For a worked example, see Loop Action Configuration.
Start Loop and End Loop
Loops consist of a 
Start Loop Action and an 
End Loop Action joined by a loop connector which returns the result of the End Node to the Start Node. Each part of the Loop has its own set of properties described below.
The key concept of a loop is that the attributes passed into it are available as passthrough as well as attributes mapped in from the End Loop. This allows the original passthrough values to be referenced and if the loop is manipulating the incoming attributes, 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 have come from, for example a calculated action.
Loops wait until all their internal nodes have completed their tasks before beginning the next iteration of a loop.
Properties Tab - Start Loop
Basic Settings
| Field | Description | Example Value |
|---|---|---|
| Name | The name given to the node and displayed on the canvas. | My Loop |
| End Loop Action | A read-only field that states the end loop node associated with the start loop node. | // The End Loop Node will initially take the name of the Start Loop // Node and prefix it with "end".
|
Output Attributes
The grid contains a list of all Output Attributes.
- To add an Output Attribute, in the section toolbar click
Add New and set its properties. - To edit an existing Output Attribute, double-click it in the list to open its properties.
- To remove an Output Attribute, select one (or more) from the list and in the section toolbar click
Delete.
Properties Tab - End Loop
Basic Settings
| Field | Description | Example Value |
|---|---|---|
| Name | The name given to the node and displayed on the canvas. The name will default to the Start Loop name prefixed with end. | End My Loop |
| Records to output | Sets whether to output all records from the loop or just the final record. | All Records or Final Record |
| Output Mode | A read-only field that states the end loop node associated with the start loop node. | // The End Loop Node will initially take the name of the Start Loop // Node and prefix it with "end".
|
| Until Expression | An 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 Node on a pipe // called in.
|
| Max Loops | This is a safety net designed to stop infinite loops. The number entered here will stop | //Defaults to 10000 10000 |
Input Parameters
Can accept a single 
Driving input connection point.
The grid contains a list of all input connection points and their type.
- To add an Input Parameter, in the section toolbar click Add New and set its properties.
- To edit an existing Input Parameter, double-click it in the list to open its properties.
- To remove an Input Parameter, select one (or more) from the list and in the section toolbar click Delete.
Input Parameters can be mapped to by clocking on the incoming connector.
Audit Tab
Audit Summary
See the Common Properties page, Audit Summary section.
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