1*9746aeb8SBrad Bishop# OpenBMC meta layer guidelines 2d078e0d2SEd Tanous 3d078e0d2SEd TanousWhile most of these could be called "rules", in specific scenarios might be 4d078e0d2SEd Tanousactively against the intended goals. This is why each guideline has a very 5d078e0d2SEd Tanouslarge "Why" section, to ensure that the intent is being met, and that if 6d078e0d2SEd Tanousexceptions to the rules exist, then can be understood and managed by the 7d078e0d2SEd Tanousproject. In general, if there's a question, and the community agrees, these 8d078e0d2SEd Tanousguidelines can be overridden on a case by case basis. 9d078e0d2SEd Tanous 10*9746aeb8SBrad Bishop## Meta layers should not patch projects that exist within the openBMC tree 11d078e0d2SEd Tanous 12*9746aeb8SBrad Bishop**Why?** 13*9746aeb8SBrad Bishop 14d078e0d2SEd TanousIn general, keeping the codebase building in the long term is difficult. 15d078e0d2SEd TanousOpening the possibility that patches exist that repo maintainers aren't aware 16d078e0d2SEd Tanousof makes it much more likely that a single machine breaks, or we have behavior 17d078e0d2SEd Tanousdifferences between two repos. 18*9746aeb8SBrad Bishop 19d078e0d2SEd TanousAlso, in general, the maintainer is there to ensure that the greater community, 20d078e0d2SEd Tanousfeatures, and codebase are prioritized over any one patch, and generally does so 21d078e0d2SEd Tanousin code review. If patches are checked into meta layers, generally the 22d078e0d2SEd Tanousmaintainer is not a reviewer, thereby defeating most of the purpose of the role 23d078e0d2SEd Tanousof the maintainer. 24d078e0d2SEd Tanous 25*9746aeb8SBrad Bishop**What should I do instead?** 26*9746aeb8SBrad Bishop 27d078e0d2SEd TanousDiscuss with the project maintainers and the community about whether or not the 28d078e0d2SEd Tanousfeature you're building needs to be configurable, or if it can be applied to all 29d078e0d2SEd Tanousprojects. If it can be applied to all, simply check it into the master branch 30d078e0d2SEd Tanousthrough a gerrit review, and follow the processes outlined for the repository. 31d078e0d2SEd TanousIf it needs to be per-project or per-machine configurable, check it in under a 32d078e0d2SEd Tanouscompile time option, at the suggestion of the maintainer, and add a 33d078e0d2SEd TanousPACKAGECONFIG entry that can be set to enable it. 34d078e0d2SEd Tanous 35*9746aeb8SBrad Bishop## Meta layers should not patch Yocto recipes and projects 36d078e0d2SEd Tanous 37*9746aeb8SBrad Bishop**Why?** 38*9746aeb8SBrad Bishop 39d078e0d2SEd TanousYocto itself is an open source project that accepts contributions. The more 40d078e0d2SEd Tanouschanges that OpenBMC stacks against Yocto recipes, the more unmaintainable it 41d078e0d2SEd Tanousbecomes, and the longer it takes to rebase to new Yocto versions. In general, 42d078e0d2SEd Tanousthe Yocto community is as responsive (sometimes much faster) than the OpenBMC 43d078e0d2SEd Tanouscommunity in regards to pull requests. 44d078e0d2SEd Tanous 45*9746aeb8SBrad Bishop**What should I do instead?** 46*9746aeb8SBrad Bishop 47d078e0d2SEd TanousSubmit any changes needed to the Yocto upstream repositories, using their 48d078e0d2SEd Tanousprocess. If the Yocto process has gone several weeks without responses, 49d078e0d2SEd Tanouscherry-pick the commit into the OpenBMC tree, with a pointer to the review in 50d078e0d2SEd Tanousthe commit message. 51d078e0d2SEd Tanous 52*9746aeb8SBrad Bishop## Meta layers should avoid using EXTRA_OEMAKE and EXTRA_OEMESON 53d078e0d2SEd Tanous 54*9746aeb8SBrad Bishop**Why?** 55*9746aeb8SBrad Bishop 56d078e0d2SEd TanousThere are some OpenBMC projects that are utilized outside of OpenBMC. As such, 57d078e0d2SEd Tanousthere are configuration items that are not intended to be used in OpenBMC, or 58d078e0d2SEd Tanousconfiguration items that would pose a security risk. Also, as options change 59d078e0d2SEd Tanousand are deprecated, the project needs a single place to update the available 60d078e0d2SEd Tanousconfig items and dependencies. 61*9746aeb8SBrad Bishop 62d078e0d2SEd TanousIn addition, subprojects might change their build tooling, for example from 63d078e0d2SEd Tanousautotools to meson, in pursuit of other goals. Having tool-specific 64d078e0d2SEd Tanousconfigurations makes that change far more difficult to do. 65d078e0d2SEd Tanous 66*9746aeb8SBrad Bishop**What should I do instead?** 67*9746aeb8SBrad Bishop 68d078e0d2SEd TanousIn the root recipe, add a PACKAGECONFIG entry for the feature in question, then 69d078e0d2SEd Tanoususe that to enable said feature in your meta layer. 70d078e0d2SEd Tanous 71*9746aeb8SBrad Bishop## Meta layers should not have recipes that point to proprietary licensed code 72d078e0d2SEd Tanous 73*9746aeb8SBrad Bishop**Why?** 74*9746aeb8SBrad Bishop 75d078e0d2SEd TanousOpenBMC is an open source project, and is intended to be built from source, with 76d078e0d2SEd Tanousappropriate distribution licenses such that it can be reused. Pointing to 77d078e0d2SEd Tanouscommercially licensed repositories actively opposes that goal. 78d078e0d2SEd Tanous 79*9746aeb8SBrad Bishop**What should I do instead?** 80*9746aeb8SBrad Bishop 81d078e0d2SEd TanousFind an equivalent open source project that meets the needs, or request that the 82d078e0d2SEd Tanousproject owner relicenses their project. 83d078e0d2SEd Tanous 84*9746aeb8SBrad Bishop## Meta layer recipes should only point to well maintained open source projects 85d078e0d2SEd Tanous 86*9746aeb8SBrad Bishop**Why?** 87*9746aeb8SBrad Bishop 88d078e0d2SEd TanousWithout this guideline, a loophole is present that allows OpenBMC developers to 89d078e0d2SEd Tanousbypass code review by pointing the upstream recipe to a public repository that 90d078e0d2SEd Tanousthey control, but which OpenBMC has no input on the content of. This splits the 91d078e0d2SEd Tanousdiscussion forums in unproductive ways, and prevents all the other good 92d078e0d2SEd Tanousprocesses within OpenBMC like bug tracking and continuous integration from 93d078e0d2SEd Tanoushaving an effect. 94d078e0d2SEd Tanous 95*9746aeb8SBrad Bishop**What should I do instead?** 96*9746aeb8SBrad Bishop 97d078e0d2SEd TanousThe advice tends to be on a case by case basis, but if the code is only intended 98d078e0d2SEd Tanousfor use on OpenBMC, then push a design doc, and push the code to openbmc gerrit 99d078e0d2SEd Tanousunder the openbmc/openbmc repository where it can be reviewed, along with an 100d078e0d2SEd TanousOWNERS file, signaling your willingness to maintain this project. Then, once 101d078e0d2SEd Tanousthe community has looked through your design, a repo will be created for code to 102d078e0d2SEd Tanousbe pushed to. If you're pulling in code from a dead project, inquire to the 103d078e0d2SEd Tanouscommunity through the mailing list or discord whether or not the OpenBMC 104d078e0d2SEd Tanouscommunity would be willing to adopt support and maintenance of said project. 105d078e0d2SEd Tanous 106*9746aeb8SBrad Bishop## Don't use SRCREV="${AUTOREV}" in a recipe 107d078e0d2SEd Tanous 108*9746aeb8SBrad Bishop**Why?** 109*9746aeb8SBrad Bishop 110d078e0d2SEd TanousRepository branches can change at any time. Pointing to an autorev revision 111d078e0d2SEd Tanousincreases the likelihood that builds break, and makes builds far less 112d078e0d2SEd Tanousreproducible. 113*9746aeb8SBrad Bishop 114d078e0d2SEd TanousIn addition, having an accounting of exactly what is in your build prevents 115d078e0d2SEd Tanouserrors when a repo is quietly updated while working, and suddenly changes 116d078e0d2SEd Tanoussignificantly. 117d078e0d2SEd Tanous 118*9746aeb8SBrad Bishop**What should I do instead?** 119*9746aeb8SBrad Bishop 120d078e0d2SEd TanousPoint SRCREV to a specific commit of the repository, and increase the revision 121d078e0d2SEd Tanouseither via the autobump script in CI, which can be requested on the mailing 122d078e0d2SEd Tanouslist, or manually as new revisions exist. 123