// -*- mode:doc; -*- // vim: set syntax=asciidoc: === Tips and tricks [[package-name-variable-relation]] ==== Package name, config entry name and makefile variable relationship In Buildroot, there is some relationship between: * the _package name_, which is the package directory name (and the name of the +*.mk+ file); * the config entry name that is declared in the +Config.in+ file; * the makefile variable prefix. It is mandatory to maintain consistency between these elements, using the following rules: * the package directory and the +*.mk+ name are the _package name_ itself (e.g.: +package/foo-bar_boo/foo-bar_boo.mk+); * the _make_ target name is the _package name_ itself (e.g.: +foo-bar_boo+); * the config entry is the upper case _package name_ with `.` and `-` characters substituted with `_`, prefixed with +BR2_PACKAGE_+ (e.g.: +BR2_PACKAGE_FOO_BAR_BOO+); * the +*.mk+ file variable prefix is the upper case _package name_ with `.` and `-` characters substituted with `_` (e.g.: +FOO_BAR_BOO_VERSION+). [[check-package]] ==== How to check the coding style Buildroot provides a script in +utils/check-package+ that checks new or changed files for coding style. It is not a complete language validator, but it catches many common mistakes. It is meant to run in the actual files you created or modified, before creating the patch for submission. This script can be used for packages, filesystem makefiles, Config.in files, etc. It does not check the files defining the package infrastructures and some other files containing similar common code. To use it, run the +check-package+ script, by telling which files you created or changed: ---- $ ./utils/check-package package/new-package/* ---- If you have the +utils+ directory in your path you can also run: ---- $ cd package/new-package/ $ check-package * ---- The tool can also be used for packages in a br2-external: ---- $ check-package -b /path/to/br2-ext-tree/package/my-package/* ---- [[testing-package]] ==== How to test your package Once you have added your new package, it is important that you test it under various conditions: does it build for all architectures? Does it build with the different C libraries? Does it need threads, NPTL? And so on... Buildroot runs http://autobuild.buildroot.org/[autobuilders] which continuously test random configurations. However, these only build the `master` branch of the git tree, and your new fancy package is not yet there. Buildroot provides a script in +utils/test-pkg+ that uses the same base configurations as used by the autobuilders so you can test your package in the same conditions. First, create a config snippet that contains all the necessary options needed to enable your package, but without any architecture or toolchain option. For example, let's create a config snippet that just enables +libcurl+, without any TLS backend: ---- $ cat libcurl.config BR2_PACKAGE_LIBCURL=y ---- If your package needs more configuration options, you can add them to the config snippet. For example, here's how you would test +libcurl+ with +openssl+ as a TLS backend and the +curl+ program: ---- $ cat libcurl.config BR2_PACKAGE_LIBCURL=y BR2_PACKAGE_LIBCURL_CURL=y BR2_PACKAGE_OPENSSL=y ---- Then run the +test-pkg+ script, by telling it what config snippet to use and what package to test: ---- $ ./utils/test-pkg -c libcurl.config -p libcurl ---- By default, +test-pkg+ will build your package against a subset of the toolchains used by the autobuilders, which has been selected by the Buildroot developers as being the most useful and representative subset. If you want to test all toolchains, pass the +-a+ option. Note that in any case, internal toolchains are excluded as they take too long to build. The output lists all toolchains that are tested and the corresponding result (excerpt, results are fake): ---- $ ./utils/test-pkg -c libcurl.config -p libcurl armv5-ctng-linux-gnueabi [ 1/11]: OK armv7-ctng-linux-gnueabihf [ 2/11]: OK br-aarch64-glibc [ 3/11]: SKIPPED br-arcle-hs38 [ 4/11]: SKIPPED br-arm-basic [ 5/11]: FAILED br-arm-cortex-a9-glibc [ 6/11]: OK br-arm-cortex-a9-musl [ 7/11]: FAILED br-arm-cortex-m4-full [ 8/11]: OK br-arm-full [ 9/11]: OK br-arm-full-nothread [10/11]: FAILED br-arm-full-static [11/11]: OK 11 builds, 2 skipped, 2 build failed, 1 legal-info failed ---- The results mean: * `OK`: the build was successful. * `SKIPPED`: one or more configuration options listed in the config snippet were not present in the final configuration. This is due to options having dependencies not satisfied by the toolchain, such as for example a package that +depends on BR2_USE_MMU+ with a noMMU toolchain. The missing options are reported in +missing.config+ in the output build directory (+~/br-test-pkg/TOOLCHAIN_NAME/+ by default). * `FAILED`: the build failed. Inspect the +logfile+ file in the output build directory to see what went wrong: ** the actual build failed, ** the legal-info failed, ** one of the preliminary steps (downloading the config file, applying the configuration, running `dirclean` for the package) failed. When there are failures, you can just re-run the script with the same options (after you fixed your package); the script will attempt to re-build the package specified with +-p+ for all toolchains, without the need to re-build all the dependencies of that package. The +test-pkg+ script accepts a few options, for which you can get some help by running: ---- $ ./utils/test-pkg -h ---- [[github-download-url]] ==== How to add a package from GitHub Packages on GitHub often don't have a download area with release tarballs. However, it is possible to download tarballs directly from the repository on GitHub. As GitHub is known to have changed download mechanisms in the past, the 'github' helper function should be used as shown below. ------------------------ # Use a tag or a full commit ID FOO_VERSION = 1.0 FOO_SITE = $(call github,,,v$(FOO_VERSION)) ------------------------ .Notes - The FOO_VERSION can either be a tag or a commit ID. - The tarball name generated by github matches the default one from Buildroot (e.g.: +foo-f6fb6654af62045239caed5950bc6c7971965e60.tar.gz+), so it is not necessary to specify it in the +.mk+ file. - When using a commit ID as version, you should use the full 40 hex characters. - When the tag contains a prefix such as +v+ in +v1.0+, then the +VERSION+ variable should contain just +1.0+, and the +v+ should be added directly in the +SITE+ variable, as illustrated above. This ensures that the +VERSION+ variable value can be used to match against http://www.release-monitoring.org/[release-monitoring.org] results. If the package you wish to add does have a release section on GitHub, the maintainer may have uploaded a release tarball, or the release may just point to the automatically generated tarball from the git tag. If there is a release tarball uploaded by the maintainer, we prefer to use that since it may be slightly different (e.g. it contains a configure script so we don't need to do AUTORECONF). You can see on the release page if it's an uploaded tarball or a git tag: image::github_hash_mongrel2.png[] - If it looks like the image above then it was uploaded by the maintainer and you should use that link (in that example: 'mongrel2-v1.9.2.tar.bz2') to specify +FOO_SITE+, and not use the 'github' helper. - On the other hand, if there's is *only* the "Source code" link, then it's an automatically generated tarball and you should use the 'github' helper function. [[gitlab-download-url]] ==== How to add a package from Gitlab In a similar way to the +github+ macro described in xref:github-download-url[], Buildroot also provides the +gitlab+ macro to download from Gitlab repositories. It can be used to download auto-generated tarballs produced by Gitlab, either for specific tags or commits: ------------------------ # Use a tag or a full commit ID FOO_VERSION = 1.0 FOO_SITE = $(call gitlab,,,v$(FOO_VERSION)) ------------------------ By default, it will use a +.tar.gz+ tarball, but Gitlab also provides +.tar.bz2+ tarballs, so by adding a +_SOURCE+ variable, this +.tar.bz2+ tarball can be used: ------------------------ # Use a tag or a full commit ID FOO_VERSION = 1.0 FOO_SITE = $(call gitlab,,,v$(FOO_VERSION)) FOO_SOURCE = foo-$(FOO_VERSION).tar.bz2 ------------------------ If there is a specific tarball uploaded by the upstream developers in +https://gitlab.com//releases/+, do not use this macro, but rather use directly the link to the tarball.