Load files from azure at startup and add new files in memory and azure storage

I have following problem, what is best approach to solve this? I have few files on azure storage I need to download existing files on startup and save them in memory cache. User can upload file on Azure storage but when he upload file I already have content so I need to save file in memory cache. When user request report I will get name of the file and make report for file contained in memory cache. Make singleton service which keeps files or create hosted service which has injected IMemoryCache and save file in memory (files are only few kb size), so when I need file I only check if file is saved in memory cache? Or there is better approcah than this?