Azure-functions-host: Node.js function takes 2-4 minutes to start after any code change

[anton-bot]

I am using Azure Functions v2.0-beta and writing timer-triggered functions in Node.js.

When I make any change to my JavaScript file, the first run of a function takes approximately 2-4 minutes instead of the usual milliseconds.

During that time, the functions consumes a large number of execution units and also the storage usage spikes a lot, with tens of thousands of read or write requests.

Here's an example of a relatively fast startup which took 2 minutes:

2018-08-17T19:22:03.001 [Information] Executing 'Functions./my function name/' (Reason='Timer fired at 2018-08-17T19:22:03.0013209+00:00', Id=3ff72e1c-8dd9-4fd9-925c-8057aac25229)

2018-08-17T19:24:06.510 [Information] Executed 'Functions./my function name/' (Succeeded, Id=3ff72e1c-8dd9-4fd9-925c-8057aac25229)

The function is running in the East Asia region.

Repro steps

1. Create a timer-triggered JavaScript function.
2. Install packages such as request and request-promise-native.
3. Try to run the function.
4. Modify the JavaScript file (e.g. add a space).
5. The first startup is slow.

Expected behavior

Expect the function to start up within a few seconds and do not consume thousands of write operations on the storage.

[anton-bot]

As an example:

• I deployed the code of my function (one or two JavaScript files) several times over half an hour;
• Each time it took 3-5 minutes for the function to start working again (I did not restart the service);
• I got charged for approximately 300,000 File operations in this function's storage account.

[mhoeger]

Hi @catcher-in-the-try, sorry about the delayed response on this. We have made a lot of changes leading to our recent GA - is this still an issue?

[mhoeger]

For functions with lots of dependencies, our recommendation is to use Run From Package with Zip Deployment (docs here: https://docs.microsoft.com/en-us/azure/azure-functions/deployment-zip-push#run-functions-from-the-deployment-package)

[FlsZen]

I found my way here after noticing my rather basic Node.js Azure Functions app was taking a few minutes to respond to the infrequent requests it receives and its storage account was reporting a large amount of write operations correlated with the requests. It looks like "Run From Package with Zip Deployment" is going to be very helpful. 😁

[mhoeger]

👍 ! We're working to make this the default deployment method everywhere too!