Can you gist the output of a deploy before and after running dokku trace on? I have a feeling that our cleanup step is removing the intermediate build layer since its not used, but getting confirmation of that would be great.

before: https://gist.github.com/ilyapoz/675d3be5799e2821220ee91857f550af
after: https://gist.github.com/ilyapoz/b9e2c4697db1b599d1193f4a804e3b3a

Can you run dokku trace off and run the deploy?

https://gist.github.com/ilyapoz/a9984e870d01f561f928f20c6907b0a2

@josegonzalez I took a look and the image from the builder phase is getting removed at: https://github.com/dokku/dokku/blob/master/plugins/common/functions#L650 as you suspected.

Not sure there is a great way around that, given our deployment methodology. Any image cleanup will break this, so perhaps having folks manage that on their own when they are using multi-stage builds is the best way?

Looks like we might be able to leverage dockfmt to list all stages in an image, and then build the image by specifying targets/tagging each layer. We'd then avoid removing tagged layers during the cleanup stage.

So my original plan won't work unless each stage is named, meaning we would have to either drop the cache-fix for non-named stages or rewrite the dockerfile to ensure each stage is named. I don't know how I feel about either, though the later method is probably possible using a fun regex and the post-extract hook.

hello, I think i have solution for this, I'm looking a way to cache my package manager dont have to reinstall every time have CI build or dokku build on server and now I have it https://github.com/dokku/dokku/blob/c1df31b106da6eb8c7897deea67c143e2b5e611a/docs/deployment/builders/dockerfiles.md
I have make an PR for the docs on here
#4635

in my case I'm using pnpm (the same like npm or yarn) and I spend about 10 minutes or 20 minutes for each time package.json file change, and with the new command, It can save me about 5 minutes build time, which save alot of money sir :

FROM node:14-alpine as builder
ENV CYPRESS_INSTALL_BINARY=0
RUN --mount=type=cache,target=/root/.pnpm-store/v3
RUN pnpm install --frozen-lockfile --prod