A custom function is code Rhythm built for your organization and deployed in Rhythm’s cloud. After you register it here, your custom record actions can find and call it. Custom order pricing is one example: your Orders setup can call a registered custom function to calculate a price, if your Rhythm contact has built that function for your organization.
This screen does not build or deploy the function. Rhythm handles that work as part of the project the function belongs to; this screen only saves the pointer your custom record actions use.
This works differently from a third-party system writing values into your custom fields through the Rhythm API. That kind of write-back does not need a registered function, because the connecting system includes those custom fields in its own API request.
Prerequisites
- The function must already be built and deployed for your organization in Rhythm’s cloud. If you are not sure, check with your Rhythm contact before you register it.
- You need the function’s exact name, which always starts with
customers_. - You need access to System & Security in the Console. No separate permission is required beyond that.
Tip
If you are testing API calls instead of using your live account, you can use Rhythm's published mock server base URI instead of your account's own custom domain.
Register a Custom Function
- Go to System & Security › Integrations, then choose the Lambda Functions card.
- Choose
Create Lambda Function. - Enter a
Name:. Rhythm fills in anID:as you type, using the name in capital letters and changing anything except letters, digits, and underscores to a dash. You can also enter your own identifier if you prefer. - Enter the exact
Lambda Function Name:your Rhythm contact gave you. - Leave
Status:onActive, or change it to inactive if you are not ready for custom record actions to use it yet. - Optionally, add a description to help you remember what the function does.
- Choose
Save Changes.
Result
Rhythm saves the registration and shows it in your custom functions list, where you can select it from a custom record action.
Settings
| Setting | Options | Default | Effect |
|---|---|---|---|
Name: | Text, required | Empty | The display name you and other staff see in the list and when you choose a function for a custom record action |
ID: | Text, required; generated from Name: on a new record, fixed after that | Generated from Name: | The permanent identifier other records use after you save; you cannot change it later |
Lambda Function Name: | Text, required | Empty | The exact function name in Rhythm’s cloud; it must start with customers_ and must already exist there |
Status: | Active or Inactive | Active | Inactive registrations are hidden from the list by default, but a custom record action already set up to use one still runs it |
| Description | Text, optional | Empty | A free-text note about what the function does |
Validation and Errors
| Message | Cause and fix |
|---|---|
"Unable to save Lambda Function" (the function's name does not begin customers_) | The Lambda Function Name: you entered does not start with customers_. Confirm the exact name with your Rhythm contact |
"Unable to locate lambda function <name>" | The name is formatted correctly as customers_..., but Rhythm cannot find a deployed function with that exact name. You also see this message if you try to save any change to a registration after its function has been removed |
| "A record already exists with this name." | The ID: you are about to save is already used by another registration in your account. Change the name or the ID |
| "Unable to delete Lambda Function", with a count of dependent records | Another record still refers to this registration, such as a custom record action. Remove or change those references first |
Clone, Change, or Deactivate a Registration
- Clone a registration from its row in the list to start a new one with the same values already filled in. A clone is a separate registration with no link back to the original, so give it its own name and confirm its
Lambda Function Name:before saving. - Change a registration by selecting it from the list, editing
Name:,Lambda Function Name:,Status:, or the description, and saving. You cannot change theID:. Custom record actions use the registration’sID:, not its function name, so changingLambda Function Name:changes what runs for every custom record action that already uses that registration. - Deactivate a registration by changing
Status:toInactiveand saving, rather than deleting it. This hides it from your list by default, while(show all)still reveals it. An inactive registration is not disabled everywhere: a custom record action already configured to use it keeps calling it.
Remove a Registration
Select Delete on the registration’s row and confirm. If anything still depends on the registration, Rhythm refuses the deletion and tells you how many records are using it. Remove or repoint those references first.
Deleting the registration removes only Rhythm’s record of it. It does not remove the function itself from Rhythm’s cloud.
Locked Registrations
Rhythm staff can lock a registration so something important is not changed or deleted by accident. A locked registration does not show edit or delete options in the list. If you need a locked registration changed or removed, contact Rhythm support.
Tip
The same locking and deactivating options described here also apply to UPS accounts elsewhere in Integrations.
Dependencies and Precedence
You cannot save, change, or reactivate a registration if Rhythm cannot find its named function for your organization at that moment. Rhythm checks that the function exists every time you save, not only when you first register it.
Change Impact and How to Revert
Changing Lambda Function Name: on an existing registration immediately changes what every custom record action using that registration calls, with no separate confirmation step. Review which custom record actions use a registration before you repoint it.
Permissions
Anyone who can sign in to the Console and open System & Security can register, change, clone, deactivate, or delete a custom function. Only Rhythm staff can lock a registration against deletion.