Comment by DrBazza

Comment by DrBazza 5 days ago

15 replies

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Your build should be this:

    build.bash <debug|release>
and that's it (and that can even trigger a container build).

I've spent far too much time debugging CI builds that work differently to a local build, and it's always because of extra nonsense added to the CI server somehow. I've yet to find a build in my industry that doesn't yield to this 'pattern'.

Your environment setup should work equally on a local machine or a CI/CD server, or your devops teams has identically set it up on bare metal using Ansible or something.

nrclark 5 days ago

Agreed with this sentiment, but with one minor modification: use a Makefile instead. Recipes are still chunks of shell, and they don’t need to produce or consume any files if you want to keep it all task-based. You get tab-completion, parallelism, a DAG, and the ability to start anywhere on the task graph that you want.

It’s possible to do all of this with a pure shell script, but then you’re probably reimplementing some or all of the list above.

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  • DrBazza 4 days ago

    > use a Makefile instead

    I was making a general comment that your build should be a single 'command'. Personally, I don't care what the command is, only that it should be a) one command, and b) 100% runnable on a dev box or a server. If you use make, you'll soon end up writing... shell scripts, so just use a shell script.

    In an ideal world your topmost command would be a build tool:

         ./gradlew build
     bazel build //...
     make debug
     cmake --workflow --preset
    Unfortunately, the second you do that ^^^, someone edits your CI/CD to add a step before the build starts. It's what people do :(

    All the cruft that ends up *in CI config*, should be under version control, and inside your single command, so you can debug locally.

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    • chubot 4 days ago

      That's exactly why the "main" should be shell, not make (see my sibling reply). So when someone needs to add that step, it becomes:

          #!/bin/sh

    step-I-added-to-shell-rather-than-CI-yaml
    make debug  # or cmake, bazel
      This is better so you can run the whole thing locally, and on different CI providers

      In general, a CI is not a DAG, and not completely parallel -- but it often contains DAGs

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  • chubot 4 days ago

    Make is not a general purpose parallel DAG engine. It works well enough for small C projects and similar, but for problems of even medium complexity, it falls down HARD

    Many years ago, I wrote 3 makefiles from scratch as an exploration of this (and I still use them). I described the issues here: https://lobste.rs/s/yd7mzj/developing_our_position_on_ai#c_s...

    ---

    The better style is in a sibling reply -- invoke Make from shell, WHEN you have a problem that fits Make.

    That is, the "main" should be shell, not Make. (And it's easy to write a dispatcher to different shell functions, with "$@", sometimes called a "task file" )

    In general, a project's CI does not fit entirely into Make. For example, the CI for https://oils.pub/ is 4K lines of shell, and minimal YAML (portable to Github Actions and sourcehut).

    https://oils.pub/release/latest/pub/metrics.wwz/line-counts/...

    It invokes Make in a couple places, but I plan to get rid of all the Make in favor of Python/Ninja.

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    • DrBazza 4 days ago

      Portability to other CI/CDs systems is an understated reason to use a single build command.

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  • dgfitz 5 days ago

    You invoke CMake/qmake/configure/whatever from the bash script.

    I hate committing makefiles directly if it can be helped.

    You can still call make in the script after generating the makefile, and even pass the make target as an argument to the bash script if you want. That being said, if you’re passing more than 2-3 arguments to the build.sh you’re probably doing it wrong.

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    • nrclark 5 days ago

      Yes to calling CMake/etc. No to checking in generated Makefiles. But for your top-level “thing that calls CMake”, try writing a Makefile instead of a shell script. You’ll be surprised at how powerful it is. Make is a dark horse.

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      • dgfitz 4 days ago

        I wouldn't be surprised at all, make is great!

        My contention is that a build script should ideally be:

        sha-bang

        clone && cd $cloned_folder

        ${generate_makefile_with_tool}

        make $1

        Anything much longer than that can (and usually will) quickly spiral out of control.

        Make is great. Unless you're code-golfing, your makefile will be longer than a few lines and a bunch of well-intentioned-gremlins will pop in and bugger the whole thing up. Just seen it too many times.

        Edit: in the jenkins case, in a jenkins build shell the clone happens outside build.sh:

        (in jenkins shell):

        clone && cd clone ./build.sh $(0-1 args)

        (inside build.sh): $(generate_makefile_with_tool) make $1

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    • lenkite 4 days ago

      I have experienced horror build systems where the Makefile delegates to a shell script which then delegates to some sub-module Makefile, which then delegates to a shell script...

      The problem is that shell commands are very painful to specify in a Makefile with weird syntactical rules. Esp when you need them to run in one shell - a lot of horror quoting needed.

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mikepurvis 4 days ago

There are various things that can be a reasonable candidate for the "top level" build entrypoint, including Nix, bazel, docker bake, and probably more I'm not thinking of. They all have an entrypoint that doesn't have a ton of flags or nonsense, and operate in a pretty self contained environment that they set up and manage themselves.

Overall I'm not a fan of wrapping things; if there are flags or options on the top-level build tool, I'd rather my devs explore those and get used to what they are and can do, rather than being reliant on a project-specific script or make target to just magically do the thing.

Anyway, other than calling the build tool, CI config can have other steps in it, but it should be mostly consumed with CI-specific add-ons, like auth (OIDC handshake), capturing logs, uploading artifacts, sending a slack notification, whatever it is.

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  • DrBazza 4 days ago

    Fortunately most CI/CD systems expose an environment variable during the build so you can detect most of those situations and still write a script that runs locally on a developer box.

    Our wrapping is 'minimal', in that you can still run

        bazel build //...
    or

        cmake ...
    and get the same build artefacts as running:

        build.bash release
    My current company is fanatical about read-only for just about every system we have (a bit like Nix, I suppose), and that includes CI/CD. Once the build is defined to run debug or release, rights are removed so the only thing you can edit are the build scripts you have under your control in your repo. This works extremely well for us.
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    • mikepurvis 4 days ago

      Interestingly despite being pretty hard-nosed about a lot of things, Nix does not insist on a read-only source directory at build time— the source is pulled into a read-only store path, but from there it is copied into the build sandbox, not bind-mounted.

      I expect this is largely a concession to the reality that most autotools projects still expect an in-source build, not to mention Python wanting to spray pyc files and build/dist directories all over the place.

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kqr 4 days ago

I tried to drive this approach at a previous job but nobody else on the team cared so I ended up always having to mirror all the latest build changes into my bash script.

The reason it didn't catch on? Everyone else was running local builds in a proprietary IDE, so to them the local build was never the same anyway.

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germandiago 4 days ago

I always use, no matter what I am using underneath, a bootstrap script, a configure script and a build step.

That keeps the cli interface easy, expectable and guessable.

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