be defensive in reading/parsing Azure Function "function.json" and "host.json"

[trentm]

The Azure Functions instrumentation assumes that "function.json" and "../host.json" exist and are valid JSON in an Azure Function. If that isn't the case, then the APM agent (and the Azure Function worker process) could crash.

Those files are specified here:

• https://learn.microsoft.com/en-us/azure/azure-functions/functions-reference
• https://learn.microsoft.com/en-us/azure/azure-functions/functions-host-json

My understanding is that a Node.js Azure Function is invalid and non-functional without those files, but I haven't tried hard to break it.

The APM agent should fallback to just not instrumenting the Azure Function (or limited instrumentation) if there is a problem reading those files.

[Grant-Visser]

function.json file has been removed in the new Azure functions 4 implementation for javascript functions, meaning this is now an incompatibility as far as I can see. Here's a stacktrace:

Message processing error (Action=ProcessMessageCallback, EntityPath=webhook-update, Endpoint=No)
System.Private.CoreLib: Exception while executing function: Functions.serviceBusQueueTrigger1. System.Private.CoreLib: Result: Failure
Exception: bindingDefinitions is not iterable
Stack: TypeError: bindingDefinitions is not iterable
    at new FunctionInfo (/project/node_modules/elastic-apm-node/lib/instrumentation/azure-functions.js:74:22)

Trying to find a way around this now.

[suhaschintala12]

@Grant-Visser

Trying to find a way around this now.

Any update on this issue? I am facing the same issue. I am using apm agent nodejs 4.5.0 and azure functions 4.1 and simple azure function setup fails with the bindingDefinitions error

[mito4ek]

Same issue for me :(

"elastic-apm-node": "4.7.0" "@azure/functions": "4.5.0"