Hi Sweta - Thanks for reaching out.
Storage doesn't provide any inbuilt mechanism to notify for SAS expiry as storage doesn't stores any SAS it's end. This is because SAS is confidential data and as part of compliance, need to be maintained on the customer side only. So, you need to maintain or track the expiry from your side only.
Alternatively, you can make use of Azure Key Vault to store the SAS and the AKV will be taking care of renewals of the same. In that way, you don't have to track the expiry at all.
Lastly, it is also encouraged to make use of Azure AD roles for authorization instead of SAS which provide better control by managing the permissions via roles.
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