How to troubleshoot Microsoft Azure WebApp on java? How to access logs?

Andrii Plotnikov :

I have a java-application (standard springboot from default tutorial: https://spring.io/guides/gs/spring-boot-for-azure/ ) that I "successfuly" deploy to my WebApp (created during deployment) via Eclipse/maven plugin azure-webapp:deploy

Once deployed, files are inside the WebApp, I can see them. If start-up is successful I do get running application, but if it is not - I do not know how to troubleshoot. I don't know where to find error logs, what caused the problem and as consequence, how to solve it.

as an example of how to make it fail, add this line:

throw new RuntimeException("Doomed to fail");

I tried enabling logs from "diagnostic logs tab" and expected to see them under LogFiles/Applications but that folder remains empty.

How do I troubleshoot java-application that fails to start in WebApps of Azure?

edit: additional example of Exception to troubleshoot:

public static void main(String[] args) {
    throw new RuntimeException("start failure #21");
    //SpringApplication.run(Application.class, args);
}

Andrii Plotnikov :

I didn't manage to find logs in windows based machine, but If you enable logs on linux-based-machine you will see them in the "Diagnostic logs" output. There is a catch though.

There is 230 timeout. It will wait full "timeout" time, until producing logs in the log file, after which you can access them via log file or through "Diagnostic logs". Make sure to enable logging before you start application. This applies to linux based machine, I don't know if it can apply to windows based machine.

Then it waits for an answer trigger. Answer trigger, as it turns out, is a phrase in console output "Application is started in X seconds". I increased the timeout to 500 seconds, because although it starts in 60 seconds on my local machine, it takes 430 seconds on remote-linux-based machine of Microsoft Azure*

Second, I changed the name of my main class from "GameStart" to "Application" and after that it actually caught the trigger. After that the application started. Nowhere in manuals did I find the "until timeout - no logs" and "trigger phrase" clauses mentioned.

ps: For reference, it took me 20 to upload application, 5 minutes to start it. I was using centralUS server, cuz centralEU did not work out for me, as it was even longer, although I'm in central EU myself

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*using test account. It might happen that on payed account number are either different or similar.