CODEWITHSUNDEEP
node.jsazureswapazure-deployment-slots
Sam
Sam

Reputation: 960

Azure Web App drops request during swap

I love the idea of swapping slots in Azure, but it doesn't seem to be working correctly.

I have a client app that is uploading files to the server, each as a separate request. When I attempt a server swap it will hang on one of the file uploads and that request will fail. Likewise, if I refresh the production slot's web page it will hang. This only happens for like 30 seconds and then everything is good, but it's enough to interrupt requests.

I read somewhere that sticky slot settings can cause this, so I disabled those but it still happens.

Any ideas? This is a nodeJs web app.

Thank you, Sam

Upvotes: 1

Views: 1039

Answers (1)

Gary Liu
Gary Liu

Reputation: 13918

As the different slots can be treated as different applications. If your request is pending on the production slot when the web app is swapping, it should fail. As we can find the reason:

Finally, the site that used to be Production and is now Staging also needs to get some settings apply, causing it to restart. Again, this is fine since it happens in the staging site.

You can try to use the try catch to get the exception, log the failed file, and try to upload this file again when your site swapping is completed.

Please refer to https://github.com/projectkudu/kudu/wiki/Understanding-site-swaps and http://ruslany.net/2015/09/how-to-warm-up-azure-web-app-during-deployment-slots-swap/ for more info about site swaps.

Upvotes: 1

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