Failed to find binding for activity function

[sschmeck]

Describe the bug

I see periodically the error message Failed to find binding when a activity function is executed.

The code is deployed as Function App.

• Operating System: Windows
• Plan: Elastic Premium

The error occurs for several activity functions of the Function App with different mismatches.

Failed to find binding "activityTrigger1" in bindings "activityTrigger3".
Failed to find binding "activityTrigger2" in bindings "activityTrigger1".
Failed to find binding "activityTrigger4" in bindings "activityTrigger5".

Investigative information

• Durable Functions extension version:

   "extensionBundle": {
    "id": "Microsoft.Azure.Functions.ExtensionBundle",
    "version": "[4.0.0, 5.0.0)"
  },
  

  The current deployment runs with ExtensionBundle 4.21.0. Therefore with DurableTask extension 2.13.7.
• durable-functions npm module version: 3.1.0
• @azure/functions npm module version: 4.2.0
• Language (JavaScript/TypeScript) and version: TypeScript 5.5.4
• Node.js version: 20.9.0

If deployed to Azure App Service

• Region: West Europe
• Timeframe issue observed: since 2025-01-29T07:05:18.6546624Z, maybe earlier since it's latest record within our retention period.

error	timestamp [UTC]	InvocationId
"Failed to find binding ""activityTrigger6"" in bindings ""activityTrigger5""."	"3/14/2025, 3:45:37.844 AM"	"ae58dce1-df6e-491e-8b32-aa35d2572081"
"Failed to find binding ""activityTrigger4"" in bindings ""activityTrigger6""."	"3/13/2025, 9:15:43.045 PM"	"bc796a04-3a67-4316-aad5-067547614220"
"Failed to find binding ""activityTrigger5"" in bindings ""activityTrigger6""."	"3/11/2025, 12:21:34.305 AM"	"4b6d14f3-3e34-40cb-9236-4ccabd510219"
"Failed to find binding ""activityTrigger5"" in bindings ""activityTrigger4""."	"2/18/2025, 4:08:53.449 PM"	"388a5b54-55f6-409d-979b-74fd8c1f8ec6"
"Failed to find binding ""activityTrigger4"" in bindings ""activityTrigger5""."	"2/18/2025, 7:30:30.897 PM"	"863a7eb8-f23d-435d-8fab-6d164f7ed166"

To share further details, I created Azure Support Request 2503170050001075.

To Reproduce
Steps to reproduce the behavior:

1. We defined and called six activity functions the following way.

   // Setup
   async function someActivity(operationEvent: OperationEvent, 
                               context: InvocationContext): Promise<ActivityResult> {
     // ..
   }
   app.activity('someActivity', { handler: someActivity });
   
   // Orchestrator usage
   context.df.callActivityWithRetry('someActivity', someRetryOptions, someParameter)
   

2. The function is deployed as Function App
   • Operating System: Windows
   • Plan: Elastic Premium

Expected behavior
The activity function should be executed.

Actual behavior
The runtime raises an error, e.g. Failed to find binding "activityTrigger4" in bindings "activityTrigger5".

[sschmeck]

Since the names of bindings seem to mismatch, might the df.app.activity implementation interfere with azure-functions-nodejs-library/src/addBindingName.ts?

It refers to Support multiple worker scenario in new framework. The Function App runs with FUNCTIONS_WORKER_PROCESS_COUNT=10. FYI.

---

The used @azure/functions version 4.2.0 relies on the more error-prone approach using a counter. Would it be an option to improve the df.app.activity by setting an explicit name as mentioned in the comment of addBindingName?