Custom source method

Build sources (for SRPM) by user-defined script.

The idea behind the script is simple, when the script is run - it’s only mandatory output is specfile, plus optionally any other file needed to successfully build a source RPM from that spec file (usually tarball(s), patches, etc.). By default we expect that the script generates the files in current working directory (resultdir=’.’).

Having turing-complete powers and Internet access - the script can do basically anything to get all the source pieces together. The only limitation is that it is executed under non-privileged user (the script is executed in mock chroot, under ‘mockbuild’ user). This brings one major obstacle that you can not install any RPM packages from within the script; if you need to have some packages pre-installed, you need to specify them “declaratively” as a list of (srpm)build-dependencies. The reasons for this design are that (a) it is easier and and safer to develop scripts which don’t require admin access, (b) it is convenient to write “portable” scripts (even though the script is executed in rpm-based mock chroot, the script itself can be easily written/tested on e.g. Gentoo) and (c) it follows the usual workflows of maintainers (install packages under root, and work the rest of the day as non-root) and mock workflow.

Required configuration for custom method

Basically you only have to specify script and chroot parameter.

  • script - scipt file content; written in any scripting language, but pay attention to specify shebang properly, e.g. #! /bin/sh for (posix) shell scripts. Also note that the interpreter might not be available by default, you might have to request its installation via builddeps argument).
  • chroot - (mock) chroot where the script is executed. By default, the fedora-latest-x86_64 chroot is used, which represents the latest stable or branched Fedora version available in Copr at the time of the build request (e.g. fedora-27-x86_64 when fedora-rawhide-x86_64 represents Fedora 28).

Optional parameters

  • builddeps - space-separated list of packages which are pre-installed into the build chroot (before the script is executed).
  • resultdir - where the script generates its output. By default, it is assumed to be current working directory.

Webhook support

The only useful webhook for custom source method is the custom web-hook. Because unlike other methods, custom method implementation doesn’t itself pay attention to webhook payload (json data used e.g. by GitLab to indicate what type of event triggered the webhok call) nor there’s any particular “clone url”.

With custom webhook, the payload parsing/analysis is left to the script (in other words it is user’s responsibility). For that purpose custom webhook handler dumps the webhook payload (if any) into file $PWD/hook_payload file (from the script POV).

For example, if GitLab’s merge-request event from contributor/project.git to owner/repo.git “calls” the custom webhook for package foo, the script has to parse the hook_payload file to detect the fact that contributor/project.git should be cloned (instead of owner/repo.git) to generate the sources.

Since this all is in user’s hands, it is not technically incorrect to have empty hook payload, e.g. it is valid to call curl -X POST <THE_CUSTOM_HOOK_URL> to trigger the custom source build method.

Examples

  • Trivial example (only spec file):

    $ cat script
    #! /bin/sh -x
    curl https://praiskup.fedorapeople.org/quick-package.spec -O
    
    $ copr add-package-custom PROJECT \
            --name quick-package \
            --script script
    
    $ copr build-package --name quick-package PROJECT # trigger the build
    
  • Simple example with Python package with git submodules and in-tree sources:

    $ cat script
    #! /bin/sh
    
    mkdir -p results
    resultdir=$(readlink -f results)
    
    set -x # verbose output
    set -e # fail the whole script if some command fails
    
    # obtain the source code
    git clone https://github.com/praiskup/resalloc --recursive --depth 1
    cd resalloc
    
    # 1. generate source tarball into resultdir
    python setup.py sdist -d "$resultdir"
    
    # 2. copy the spec file into resultdir, change the release number so each build
    #    has unique name-version-release triplet
    cd rpm
    release='~'$(date +"%Y%m%d_%H%M%S")
    sed "s/\(^Release:[[:space:]]*[[:digit:]]\+\)/\1$release/" resalloc.spec \
        > "$resultdir"/resalloc.spec
    
    # 3. copy other sources
    cp *.service "$resultdir"
    
    $ copr add-package-custom PROJECT \
            --name resalloc \
            --script script \
            --script-resultdir results \
            --script-builddeps 'git' \
            --script-chroot fedora-rawhide-x86_64
    
    $ copr build-package --name resalloc PROJECT # trigger the build
    
  • slightly more complicated examples are documented in this blog post about CI/CD with Copr.