Most package managers were designed for laptops with warm caches, not ephemeral Docker builds that start clean every time: https://nesbitt.io/2026/02/15/separating-download-from-install-in-docker-builds.html
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@andrewnez yeah I have no doubt that the central "phone home" points for all the major package systems have gotten hammered in recent years. between ubiquitious cloud CI/CD, then Docker then add in LLM agents, yikes...
@andrewnez one smol note: You can use pip wheel to create a "wheelhouse" while keeping the install step separated still!
@pradyunsg ah nice, i'll update the post
@andrewnez Hmm, given that layers are just tarballs anyway, I wonder how caching in a layer compares performance wise to caching the cache directly. I guess the image level caching would avoid the cache upload step after each run.
@andrewnez thanks for looking into this. It’s an uphill battle just to get colleagues to care about being a good open source citizen and not downloading all the packages on every build. I can’t imagine the cumulative cost of this waste across all developers.