Loop block in Architect not iterating JSON array from Data Action for OTel trace injection

I’m hitting a wall trying to iterate over a JSON array returned from a custom Data Action using the Loop block in Genesys Cloud Architect. The goal is to process each item in the array to inject specific trace IDs into my OpenTelemetry spans before the conversation proceeds to the IVR.

The Data Action calls an internal endpoint that returns a list of trace contexts. Here’s the response payload:

{
 "statusCode": 200,
 "body": {
 "traceIds": [
 {"id": "abc-123", "service": "auth"},
 {"id": "def-456", "service": "billing"}
 ]
 }
}

In Architect, I map response.body.traceIds to the Loop block’s input. I’ve set the loop variable to currentTrace. Inside the loop, I try to use {{currentTrace.id}} to set a participant variable for downstream tracing. However, the loop seems to skip entirely or only process the first item. The trace logs show the loop count as 1, even though the array has two elements.

I’ve verified the Data Action output in the Genesys Cloud UI, and the array structure is correct. I’m also checking the Loop configuration settings, but I can’t find any obvious misconfiguration. Is there a specific way to handle JSON arrays in the Loop block, or is this a known issue with nested objects?

Here’s the relevant part of the Architect flow configuration:

• Data Action: GetTraceContexts
• Output Mapping: response.body.traceIds → Loop Input
• Loop Variable: currentTrace
• Action inside Loop: Set Participant Variable trace_id = {{currentTrace.id}}

Any insights on how to correctly iterate over this array? I need to ensure each trace ID is processed individually to maintain the distributed tracing chain.

The Loop block in Architect doesn’t natively parse JSON strings. You’re likely passing the raw body string into the loop, which treats it as a single item rather than an array. You need to parse it first.

Use a Set Value block before the Loop. Set the source to your Data Action’s response body and use the jsonParse function if you’re on a recent patch, or better yet, handle the parsing in the Data Action itself so Architect receives an actual array object. If you must parse it in Architect, the expression looks like this:

jsonParse(${dataActionResponse.body})

Then, feed that parsed variable into the Loop block’s “Input Collection”. Make sure the “Current Item” variable is referenced correctly inside the loop. For your OTel trace injection, you’ll probably want to set a conversation attribute or a flow variable using the current item’s value.

Here’s a quick config snippet for the Set Value block that precedes the loop:

{
 "blockType": "SetValue",
 "name": "ParseTraceArray",
 "settings": {
 "destination": {
 "referenceName": "traceArray",
 "type": "flowVariable"
 },
 "source": {
 "value": "jsonParse(${myDataAction.body})",
 "type": "expression"
 }
 }
}

If jsonParse isn’t available in your region’s Architect version (sometimes it lags), switch the Data Action to return application/json and ensure the response body is directly iterable. Some older versions require the Data Action to output the array directly without wrapping it in a body object. Check the Data Action’s output schema. If it’s wrapped, unwrap it.

Also, verify your OTel SDK is actually picking up the flow variable. Architect sets the variable, but the tracing agent needs to be configured to read it from the conversation metadata. I’ve seen cases where the variable is set but the span isn’t tagged because the agent config misses the prefix. Check your genesys-cloud-tracing config for variable mapping.

One more thing: if the array is large, the Loop might timeout. Architect has a step limit. If you’re processing more than 50 items, consider batching or moving this logic to the Data Action side. It’s faster and less prone to flow failures.