What happens when azure app service receives build artifacts?

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What happens when azure app service receives build artifacts?

CHANG Caleb 1

After a .jar file is successfully deployed to an instance of azure app service, what does azure app service do with the file? I've see that my .jar file is copied into the wwwroot directory, however, I cannot see the web application running when I go to the site url. Does the app service automatically run the jar file? Do I need to rename the jar file to app.jar? I am using the azure app service deploy task from azure pipelines to deploy the build artifact.

The logs for azure app service say it runs the parking page.

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Answer 1

Ryan Hill 30,281 Microsoft Employee Moderator

Hi @CHANG Caleb ,

App Service will automatically run your artifact if it's named app.jar. However, if your deployed app is named something else, you can set Startup Command to java -jar /home/site/wwwroot/myapp.jar under Configuration | General Settings blade. Configure Java Apps provides information on configuration like JAVA_OPTS, troubleshooting, as well as pinning your Java version.

You already enabled logging on your App Service and not much was revealed. Feel free to post any snippets and OS type for another set of eyes. Another place to check is the Diagnose and solve problems, specifically check Web App Down. Also check the deployment logs for anything that may have gone wrong. For Java, those are logs are at D:\home\LogFiles\Application.

Takahito Iwasa 4,851 MVP Volunteer Moderator

Hi. @CHANG Caleb

As @Ryan Hill advises, if you know the OS, stack, etc. of the App Service, you should be able to see the initial behavior when the App Service starts by accessing it remotely and checking the startup script.

For example, the following is a Java 11 SE, Linux startup script. Analyzing this will give you an idea of how the application is launched.

   74f60d1746e6:/home# cat /bin/init_container.sh  
   #!/usr/bin/env bash  
     
   :  
     
   # If no app is published at /home/site/wwwroot/app.jar, use the parking page app.  
   # If an app is published, the default behavior is to copy the app to a local location, unless:  
   # 1. WEBSITE_SKIP_LOCAL_COPY is defined to 1 or TRUE, OR,  
   # 2. Local cache is enabled, in which case making a local copy again is unnecessary.  
   if [ ! -f /home/site/wwwroot/app.jar ]  
   then  
       APP_JAR_PATH=/usr/local/appservice/parkingpage.jar  
       echo "Using parking page app with APP_JAR_PATH=$APP_JAR_PATH"  
   elif [[ ! -z "$WEBSITE_LOCALCACHE_READY" || "$WEBSITE_SKIP_LOCAL_COPY" = "1"  || "$WEBSITE_SKIP_LOCAL_COPY" = "true" ]]  
   then  
       APP_JAR_PATH=/home/site/wwwroot/app.jar  
       echo "No local copy needed. APP_JAR_PATH=$APP_JAR_PATH"  
   else  
       mkdir -p /local/site  
       cp -r /home/site/wwwroot /local/site/wwwroot  
       APP_JAR_PATH=/local/site/wwwroot/app.jar  
       echo "Made a local copy of the app and using APP_JAR_PATH=$APP_JAR_PATH"  
   fi

Siju Mathew 1 Reputation point

2023-10-03T09:03:59.7633333+00:00

The whole process is so buggy that I cannot imagine what kind of randomness is there. I do deploy a jar and for some reason I see an old jar still there in the kudu. A restart does not save it. Somehow it is stored in some magical cache and copied it. And when the application starts it at times uses that old jar to make my life exciting. How does Microsoft manage such randomness.

The microsoft employee statement that it will run only if it is named app.jar is false. It runs the file present there that is *.jar and randomly pick one. The fact that Microsoft keeps an old version (absolute mystery how that is achieved. Perfect microsoftiness) makes it impossible situation for me. Microsoft employs just randomly replies without looking at what is really happening. Disfunctional!!

I'm trying to now rename it to app.jar before deploying. How that old jar is copied in is a mystery. I guess also to Microsoft guys. Not present in any documentation or explained anywhere. Microsoft LOL

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What happens when azure app service receives build artifacts?

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