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Hi, I'm trying to deploy my NodeJS/React app to Azure App Service, and have turned on Web sockets option in Configuration > Web sockets > On, and restarted the instance. However, I still encounter "Error during WebSocket handshake: Unexpected response code: 503" on the application. Can anyone advise on this?
Update: Found the answer that I need. I can change startup command in Configuration > General settings > Startup Command. By default, it's using "npm start" which is meant for development only (for React).
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Hi, I'm having the same error/warning. How did you solved this?
You said that by default, the webapp is using "npm start" in Configuration > general settings > startup command but in my case the box was empty. Should I write "npm start" inside the startup command box? or what should I write exactly
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Thanks for asking question! Could you please double check on ports, As Azure WebApps only listens on port 80 & 443, You may check below link:
https://github.com/projectkudu/kudu/wiki/Azure-Web-App-sandbox#network-endpoint-listening
Also there is limits of websockets per app service instance for different tier, please see
Hi Sneha, thanks for your answer, however I think port 80 and 443 should be already used by web server. The main issue seems to be because even though kudu automatically run "npm run build" to generate the production files. It doesn't automatically point the document entry to React production build which is available in folder "build/index.html". How can I change the default document entry in Linux instance to "build/index.html"?
@Mr Robi You may explicitly try creating the default document index.html as per https://learn.microsoft.com/en-us/azure/app-service/configure-common#default-documents
If this does not work, please create the iisnode.yml file to get more information around it. https://blogs.msdn.microsoft.com/azureossds/2018/08/03/debugging-node-js-apps-on-azure-app-services/
Hi Samir, thanks for the answer. However, when I select Node as the "Runtime stack", I can only select Linux as the operating system. And on Linux App Service, the Default documents tab is not available under Configuration. The iisnode.yml solution seems to be catering to Windows as well.