Call integration multiple times in parallel

Question

I have a scenario where I need to call an integration multiple times for an array of items. 
 That needs to be done in parallel as the result is then presented to the user in a form. 
 The problem I have is that I need to save the output of the function (the output of the api is then processed further) 
 in a process variable, and I am not sure how to do that. If I set a node to run multiple times with an output 
 variable, when all the instances end it will have saved only the result of the first instance (which is a CDT), while I would 
 like the output variable to contain an array with all the replies. How can this be done?

Harsha Sharma · Answer

You need a multiple output variable to store outputs of integration in an array. After a successful integration run, in the output node instead of using Operator 'is stored as', create a custom output using operator 'is stored at index' of the output variable. 
 Example, if you have 5 array items then as per my understanding process will call 5 integration nodes or the same integration nodes 5 times using MNI. Think of each node as index 1 to 5 of integrations and save output at respective index. For 3rd integration store output at index 3 of output variable and so on. If using MNI you can use tp!instanceIndex as well to store at particular index of output variable. 
 However I have never tried this scenario with an MNI yet so after trying you can let me know how it goes!

Shubham Aware · Answer

Enable MNI on the Call Integration node, point it at your input array, then in the Data tab set the custom output to your array-typed process variable and choose “Appended as” (not “Stored as”); System will automatically add each instance’s result to that variable so, when all instances finish, you have one array containing every response.

Mathieu Drouin · Answer

I would use an expression like Stefan has suggested. Much easier to debug and troubleshoot IMO.