September 25, 2022 3:18 PM, "david larsson" <david.lars...@selfhosted.xyz> wrote:
> On 2022-09-25 19:28, jgart wrote: > >> What would be the best way to illustrate the levels of nesting and code >> paths that get traversed when building a Guix package? >> I'd like to make some sequence diagram notation or something else to >> better understand what happens in a visual way. >> wdyt > > I like your idea! I'm probably not the most qualified person to answer it, > since I am (also?) > mainly using guix as a sparetime "hobby", but still very interested in > learning more about it on a > deeper level, which is a challenge. Some visual aids would definitely be > helpful. > > I think a shell of an answer would be to link together the following things > in such a diagram: > > 1. gexps > 2. the store > 3. derivations > 4. build systems > 5. a package > > Building a package in the repl, kind of illustrates the code paths via code > modules used: > > scheme@(guix-user)> ,use (guix gexp) > scheme@(guix-user)> ,use (guix store) > scheme@(guix-user)> ,use (guix derivations) > scheme@(guix-user)> ,use (gnu packages bash) > > However, in my opinion, the reason we look for the diagram is partially bcs > of that the concepts of > the related things are relatively high level so that it takes a while to > grasp them, just like > monads or maybe higher order functions. > > However, to continue the repl example: > > scheme@(guix-user)> (define (sh-symlink) > (gexp->derivation "sh" > #~(symlink (string-append #$bash "/bin/bash") > #$output))) > scheme@(guix-user)> (build-derivations (open-connection) `(,(run-with-store > (open-connection) I think you can also do a ,build derivation This link has more info: https://issues.guix.gnu.org/56114 > (sh-symlink)))) > $1 = #t > > Now if you run just the (run-with-store (open-connection) (sh-symlink)) you > will see the derivation > path output, and if you then open a new terminal you can cat > /gnu/store/shcvi6d1vgry26sq1i3qdmgsmh0n6wmi-sh.drv to see the build script > without building it. > > Now, to build a "package" after above code is loaded: > scheme@(guix-user)> ,use (guix packages) > scheme@(guix-user)> (build-derivations (open-connection) > `(,(package-derivation (open-connection) > bash))) > substitute: updating substitutes from 'https://ci.guix.gnu.org'... 100.0% > fetching path `/gnu/store/vk4r0x7baig8jnmsqrgrqpyq8qxr4gm3-bash-5.0.16-doc'... > Downloading > https://ci.guix.gnu.org/nar/lzip/vk4r0x7baig8jnmsqrgrqpyq8qxr4gm3-bash-5.0.16-doc... > bash-5.0.16-doc 290KiB 750KiB/s 00:00 [##################] 100.0% > $2 = #t > > And to only "inspect" it (so you can cat the /gnu/store/paths): > scheme@(guix-user)> (package-derivation (open-connection) bash) > $4 = #<derivation /gnu/store/cklj3xvrzrc930qwj1brmwr2dz4zbgd6-bash-5.0.16.drv > => > /gnu/store/vk4r0x7baig8jnmsqrgrqpyq8qxr4gm3-bash-5.0.16-doc > /gnu/store/v1xc4405s7xilmwhhkdj8z55wa2wlr8y-bash-5.0.16-include > /gnu/store/87kif0bpf0anwbsaw0jvg8fyciw4sz67-bash-5.0.16 7fc3d283e500> > > Concepts: > - code staging or "delayed evaluation" concepts > - what is the store and what is a build environment > - what is a derivation > - and finally build systems (normal build steps) and a package (incl. > dependency graphs). > > The start reference point: > https://guix.gnu.org/manual/en/html_node/Defining-Packages.html > > I hope above helps. > > Best regards, > David
