Application error

Question

I am trying to deploy a Flask app.
It runs successfully in localhost and also the build and deploy in github actions is successful as well.

The Flask app , just renders a template and nothing else. It is a simple one.

But when i click on the domain/link it is showing application error. I am a student and trying it for the first time . I cant figure out where is the issue.
Here is a screenshot of the issue.

Answer 1

@Ashrith S Vasist , Apologies for the delayed response.

 

I see that the WebApp is currently stopped.

Based on the info you have shared, after checking the internal logs, I see errors: 503

503.0 and 504.0 errors. Typically, the HTTP 504 indicates timeout.

 

I notice that most of the HTTP 504 are failing after 240 seconds. Azure Load Balancer has a default idle timeout setting of four minutes, it is the maximum amount of time that a request can take without sending any data back to the response. It is not configurable. Below are few methods to overcome this issue :

Azure Load Balancer has a default idle timeout setting of four minutes, it is the maximum amount of time that a request can take without sending any data back to the response. It is not configurable. Please check this FAQ: Why does my request time out after 230 seconds?

 

Kindly checkout the following approaches to overcome this issue :

A. Optimize code to finish execution within 240 seconds or send some data back at regular intervals to keep the connection alive.

**
B.**  If sending data back to keep connection alive is not feasible, consider using async pattern. I That is:

• First request starts with the script and returns an HTTP 202
• Subsequent requests from clients check the progress, and eventually return 200 when it's done.

C: Leverage background processing for long running tasks. E Please check this example: Azure Web Jobs or Azure Function Apps, 

 

D. As a quick step to isolate the issue, you may scale-up the App Service Plan and see if it helps.
( you may later scale-down, as required)

  Checkout the log directory/location information:  
Access log files and Enable and review logs to fetch more details about the error.

Kindly let us know, I'll follow-up with you further.

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