How to configure cache duration in Front Door without depending on origin's Cache-Control header?

Question

I have an Azure Blob Storage that I'd like to put Azure Front Door in front of it. This Blob Storage was previously behind Azure CDN from Edgio which is getting deprecated. In Azure CDN from Edgio it was possible to configure cache duration in the UI without depending on the origin's Cache-Control header. How to achieve the same thing with Azure Front Door?

Motivation: I have a huge number of blobs, and Azure Blob Storage requires setting Cache-Control per blob. So, I don't want to have to run a script on all of these blobs every time I decide to change cache policy.

So, how to set cache duration in Azure Front Door itself, if possible?

Thank you.

Answer 1

Hi @Hossam El-Deen

Welcome to Microsoft Q&A Platform. Thank you for reaching out & hope you are doing well.

Please take a look at the below points to achieve your requirement with Azure Front door:

• Azure Front Door rules Engine is the key to customizing caching behavior. You can define rules that match specific content patterns and apply actions, including setting cache duration. For your reference: https://learn.microsoft.com/en-us/azure/frontdoor/front-door-rules-engine-actions?tabs=portal&pivots=front-door-standard-premium
• Within a rule, use the cache action to override the origin's caching directives. For your reference: https://learn.microsoft.com/en-us/azure/frontdoor/front-door-caching?pivots=front-door-standard-premium
• You can take a look at the below three options for Cache behavior in azure Front door: Override always: Front Door will ignore any Cache-Control headers from your blobs and use the duration you specify. This is likely the option you'll want. Override if origin missing: Front Door will use your specified duration only if the origin doesn't provide caching instructions. Honor origin: Front Door will respect the Cache-Control headers from your blobs. For your reference: https://learn.microsoft.com/en-us/azure/frontdoor/front-door-caching?pivots=front-door-standard-premium#cache-behavior-and-duration
• When you choose "Override always" or "Override if origin missing", you'll be able to set the desired cache duration (up to 366 days). For your reference: https://learn.microsoft.com/en-us/azure/frontdoor/front-door-rules-engine-actions?tabs=portal&pivots=front-door-standard-premium#:~:text=Cache%20duration,mm%3Ass.
• Default caching: If no matching rule is found, Azure Front Door applies a default cache duration between 1 and 3 days if no Cache-Control header is present.
• Cache purge: Remember that you can purge the Azure Front Door cache if you need to invalidate cached content before its expiration. For your reference: https://learn.microsoft.com/en-us/azure/frontdoor/standard-premium/how-to-cache-purge#configure-cache-purge

Kindly let us know if the above helps or you need further assistance on this issue.

Please don’t forget to close the thread by clicking "Accept the answer" wherever the information provided helps you, as this can be beneficial to other community members.

Thanks,

Sai.