The conan-center-index (this repository) contains recipes for the remote JFrog ConanCenter. This remote is added by default to a clean installation of the Conan client. Recipes are contributed by opening pull requests as explained in the sections below. When pull requests are merged, the CI will upload the generated packages to the conancenter remote.
- Request access
- Submitting a Package
- Recipe files structure
- How to provide a good recipe
- Test the recipe locally
- Debugging failed builds
1️⃣ The first step to add packages to ConanCenter is requesting access. To enroll in ConanCenter repository, please write a comment requesting access in this GitHub issue. Feel free to introduce yourself and your motivation to join ConanCenter.
This process helps conan-center-index against spam and malicious code. The process is not not automated on purpose and the requests are generally approved on a weekly basis.
⚠️ The requests are reviewed manually, checking the GitHub profile activity of the requester to avoid a misuse of the service. In case of detecting a misuse or inappropriate behavior, the requester will be dropped from the authorized users list and at last instance even banned from the repository.
2️⃣ To contribute a package, you can submit a Pull Request to this GitHub repository https://github.com/conan-io/conan-center-index.
The specific steps to add new packages are:
- Fork the conan-center-index git repository, and then clone it locally.
- Copy a template from package_templates folder in the recipes/ folder and rename it to the project name (it should be lower-case). Read templates documentation to find more information.
- Make sure you are using the latest Conan client version, as recipes might evolve introducing features of the newer Conan releases.
- Commit and Push to GitHub then submit a pull request.
- Our automated build service will build 100+ different configurations, and provide messages that indicate if there were any issues found during the pull request on GitHub.
3️⃣ When the pull request is reviewed and merged, those packages are published to JFrog ConanCenter and available for everyone.
The build service associated to this repo will generate binary packages automatically for the most common platforms and compilers. See the Supported Platforms and Configurations page for a list of generated configurations. For a C++ library, the system is currently generating more than 100 binary packages.
⚠️ Note: This not a testing service, it is a binary building service for package released. Unit tests shouldn't be built nor run in recipes by default, see the FAQs for more. Before submitting a pull request, please ensure that it works locally for some configurations.
- The CI bot will start a new build only after the author is approved. Your PR may be reviewed in the mean time, but is not guaranteed.
- The CI system will also report with messages in the PR any error in the process, even linking to the logs to see more details and debug.
The pipeline will report errors and build logs by creating a comment in the pull-request after every commit. The message will include links to the logs for inspecting.
Packages generated and uploaded by this build service don't include any user or channel (existing references with any @user/channel should be considered as deprecated in favor of packages without it). Once the packages are uploaded, you will be able to install them using the reference as name/version (requires Conan >= 1.21): conan install cmake/3.18.2@.
Every entry in the recipes folder contains all the files required by Conan to create the binaries for all the versions of one library. Those
files don't depend on any other file in the repository (we are not using python_requires) and every pull-request can modify only one of those
folders at a time.
This is the canonical structure of one of these folders, where the same conanfile.py recipe is suitable to build all the versions of the library:
.
+-- recipes
| +-- library_name/
| +-- config.yml
| +-- all/
| +-- conanfile.py
| +-- conandata.yml
| +-- test_package/
| +-- conanfile.py
| +-- CMakeLists.txt
| +-- test_package.cpp
| +-- test_v1_package/
| +-- conanfile.py
| +-- CMakeLists.txt
If it becomes too complex to maintain the logic for all the versions in a single conanfile.py, it is possible to split the folder all into
two or more folders, dedicated to different versions, each one with its own conanfile.py recipe. In any case, those folders should replicate the
same structure.
This file lists the versions and the folders where they are located:
versions:
"1.1.0":
folder: 1.x.x
"1.1.1":
folder: 1.x.x
"2.0.0":
folder: all
"2.1.0":
folder: allThis file lists all the sources that are needed to build the package: source code, patch files, license files,... any file that will be used by the recipe
should be listed here. The file is organized into two sections, sources and patches, each one of them contains the files that are required
for each version of the library. All the files that are downloaded from the internet should include a checksum, so we can validate that
they are not changed.
A detailed breakdown of all the fields can be found in conandata_yml_format.md. We strongly encourage adding the patch fields to help track where patches come from and what issue they solve.
Inside the conanfile.py recipe, this data is available in a self.conan_data attribute that can be used as follows:
def export_sources(self):
for patch in self.conan_data.get("patches", {}).get(self.version, []):
files.copy(self, p["patch_file"], self.recipe_folder, self.export_sources_folder)
def source(self):
files.get(self, **self.conan_data["sources"][self.version], destination=self.source_folder, strip_root=True)
def build(self):
files.apply_conandata_patches(self)
[...]More details can be found in the reviewing preference documentation
The main files in this repository are the conanfile.py ones that contain the logic to build the libraries from sources for all the configurations,
as we said before there can be one single recipe suitable for all the versions inside the all folder, or there can be several recipes targetting
different versions in different folders. For mainteinance reasons, we prefer to have only one recipe, but sometimes the extra effort doesn't worth
it and it makes sense to split and duplicate it, there is no common rule for it.
Together with the recipe, there can be other files that are needed to build the library: patches, other files related to build systems,
... all these files will usually be listed in exports_sources and used during the build process.
Also, every conanfile.py should be accompanied by one or several folder to test the generated packages as we will see below.
All the packages in this repository need to be tested before they join ConanCenter. A test_package folder with its corresponding conanfile.py and
a minimal project to test the package is strictly required. You can read about it in the
Sometimes it is useful to test the package using different build systems (CMake, Autotools,...). Instead of adding complex logic to one
test_package/conanfile.py file, it is better to add another test_<something>/conanfile.py file with a minimal example for that build system. That
way the examples will be short and easy to understand and maintain. In some other situations it could be useful to test different Conan generators
(cmake_find_package, CMakeDeps,...) using different folders and conanfile.py files (see example).
When using more than one test_<something> folder, create a different project for each of them to keep the content of the conanfile.py and the
project files as simple as possible, without the need of extra logic to handle different scenarios.
.
+-- recipes
| +-- library_name/
| +-- config.yml
| +-- all/
| +-- conanfile.py
| +-- conandata.yml
| +-- test_package/
| +-- conanfile.py
| +-- CMakeLists.txt
| +-- main.cpp
| +-- test_cmakedeps/
| +-- conanfile.py
| +-- CMakeLists.txt
| +-- conanfile.py
The CI will explore all the folders and run the tests for the ones matching test_*/conanfile.py pattern. You can find the output of all
of them together in the testing logs.
Note.- If, for any reason, it is useful to write a test that should only be checked using Conan v1, you can do so by using the pattern
test_v1_*/conanfile.pyfor the folder. Please, have a look to linter notes to know how to prevent the linter from checking these files.
Remember that the
test_<package>recipes should test the package configuration that has just been generated for the host context, otherwise it will fail in crossbuilding scenarios.
The recipes available in CCI can be used as good examples, you can use them as the base for your recipe. However it is important to note Conan features change over time and our best practices evolve so some minor details may be out of date due to the vast number of recipes.
If you are looking for header-only projects, you can take a look on header-only template. Also, Conan Docs has a section about how to package header-only libraries.
For C/C++ projects which use CMake for building, you can take a look on cmake package template.
Another common use case for CMake based projects, both header only and compiled, is modeling components to match the find_package and export the correct targets from Conan's generators. A basic examples of this is cpu_features, a moderate/intermediate example is cpprestsdk, and a very complex example is OpenCV.
However, if you need to use autotools for building, you can take a look on libalsa, kmod, libcap.
Many projects offer pkg-config's *.pc files which need to be modeled using components. A prime example of this is Wayland.
For cases where a project only offers source files, but not a build script, you can add CMake support, but first, contact the upstream and open a PR offering building support. If it's rejected because the author doesn't want any kind of build script, or the project is abandoned, CCI can accept your build script. Take a look at Bzip2 and DirectShowBaseClasses as examples.
ℹ️ For exceptional cases where only system packages can be used and a regular Conan package may result in an incompatible and fragile package, a separated system package may be created. See the FAQs for more.
The SystemPackageTool can easily manage a system package manager (e.g. apt,
pacman, brew, choco) and install packages which are missing on Conan Center but available for most distributions. It is key to correctly fill in the cpp_info for the consumers of a system package to have access to whatever was installed.
As example there is xorg. Also, it will require an exception rule for conan-center hook, a pull request should be open to allow it over the KB-H032.
Some project requirements need to respect a version constraint. This can be enforced in a recipe by accessing the dependencies attribute.
An example of this can be found in the fcl recipe.
def validate(self):
foobar = self.dependencies["foobar"]
if self.info.options.shared and Version(foobar.ref.version) < "1.2":
raise ConanInvalidConfiguration(f"{self.ref} requires 'foobar' >=1.2 to be built as shared.")Certain projects are dependant on the configuration (a.k.a options) of a dependency. This can be enforced in a recipe by accessing the options attribute.
An example of this can be found in the sdl_image recipe.
def validate(self):
foobar = self.dependencies["foobar"]
if not foobar.options.enable_feature:
raise ConanInvalidConfiguration(f"The project {self.ref} requires foobar:enable_feature=True.")The system will use the conan-center hook to perform some quality checks. You can install the hook running:
conan config install https://github.com/conan-io/hooks.git -sf hooks -tf hooks
conan config set hooks.conan-centerThe hook will show error messages but the conan create won’t fail unless you export the environment variable CONAN_HOOK_ERROR_LEVEL=40.
All hook checks will print a similar message:
[HOOK - conan-center.py] post_source(): [LIBCXX MANAGEMENT (KB-H011)] OK
[HOOK - conan-center.py] post_package(): ERROR: [PACKAGE LICENSE] No package licenses found
Call conan create . lib/1.0@ -pr:b=default -pr:h=default in the folder of the recipe using the profile you want to test. For instance:
cd conan-center-index/recipes/boost/all
conan create conanfile.py boost/1.77.0@ -pr:b=default -pr:h=defaultThe hooks are updated from time to time, so it's worth keeping your own copy of the hooks updated regularly. To do this:
conan config installLinters are always executed by Github actions to validate parts of your recipe, for instance, if it uses migrated Conan tools imports. All executed linters are documented in linters.md. To understand how to run linters locally, read V2 linter documentation.
Go to the Error Knowledge Base page to know more about Conan Center hook errors.
Some common errors related to Conan can be found on troubleshooting section.
To test with the same enviroment, the build images are available.