How do you update function app with new docker container?

Question

I am trying to understand how to properly update a function app when a new updated docker container is required. I am using a GitHub action to build and deploy the docker image to an Azure registry; which works without issue. Then I associate that newly created image with an existing function app. This does not appear to work as no matter what I do the same (older) image is loaded. I found, mentioned here, that if I recreate the function app then it will pick up the latest image.

Should I need to recreate a function app each time? I would think that if the DOCKER_CUSTOM_IMAGE_NAME was specified that it would pick up the referenced image (which is not happening). I have tried different image names; however, the function app appears to continue to use the old image and not the reference to the updated one. I have downloaded the image from the repository and the image is built/working as I would expect, but this is not the image the function app is loading.

Due to changes with Azure Functions version 4, I am required to build a custom image to get all the underlying libraries required. Would someone please be able to give me some further insight into this? I would hate to have to recreate the function app each time I need to deploy an updated version, not to mention the headache of moving the configuration from one to the other so that it is properly configured.

Answer 1

I believe I found my issue. The function app was previously built from a package. It appears that this setting is still enabled even though the WEBSITE_RUN_FROM_PACKAGE has been set to 0 and or deleted. The image is updated/loaded as expected; however, the old package is overwriting the /home/site/wwwroot contents.

I have not found a way to use only the image and not the old package, so it looks like I may have to recreate the function app. At least with this, I will only need to recreate once instead of each time a deployment is required.

Answer 2

For those that may stubble upon this thread, I needed to remove several parameters that were causing the software package to be picked up and installed in the /home/site/wwwroot directory. Once the parameters that were causing the software to overwrite in /home/site/wwwroot everything was good to go. No need to recreate the function app once the configuration parameters were updated.