Building with Conan

General

Conan is an open source, decentralized and multi-platform package manager to create and share native binaries.

To learn more about Conan itself you can visit Conan.

Conan is used in the openPASS project to create and manage the binaries of the used ThirdParty libraries.

Additional Prerequisites

To be able to work with Conan it´s necessary to add additional packages.

Windows (MSYS2)Linux (Debian Bullseye)

pip install conan

Export Recipes

Note

A recipe is python file, which is used by conan to build and create a package. In this file there are several hooks available, which can be used for several tasks. E.g. Retrieving the source files, building from source, configuring dependencies, packaging, etc. Visit Conan. for detailed information about recipes.

To make Conan aware and to use the custom recipes for the ThirdParty libraries, these recipes have to be exported to the local cache of Conan. This can be done in different ways.

Conan Export

cd <path to conanfile.py of recipe>
conan export . <optional user>/<optional channel>

The optional user and channel flags can be used to export a recipe while it´s still in development. In that case there could be several different versions and their corresponding binaries of the same library available at the same time. The local cache could then show the following packages. E.g.

packagename/3.2.0
packagename/3.2.0@openpassWG/stable
packagename/3.3.0@myUserName/testing

Note

At least this step has to be done in prior before any ThirdParty library can be installed by Conan. Every upcoming step is optional, but can be useful while developing or debugging. Also with these steps it´s possible to install ThirdParty libraries separately.

Conan Install

Conan is now able to differentiate different version and the user can now install exactly the version he wishes to.

conan install <package_name>

This command has a look into the local cache for the recipe and the binaries of the package and installs them into the local cache. If no binaries where found an error is thrown.

Note

To make conan also build the package the command can be appended with the following argument: --build=missing.

Conan Create

Both of the previous commands can be combined with the create` command. What it basically does is calling export and install after another.

cd <path to conanfile.py of recipe>
conan create . <optional user>/<optional channel>

At this step the binaries of this package are now available in the local cache.

Note

There are several additional commands, arguments and fields for these commands available. Please see Conan Docs for additional information.

Build openPASS

If you followed the previous steps and export all dependencies and openPASS recipes to Conans local cache, then you can go on with the next steps. If not then at least the export should be done. Else Conan is not able to know how to build the dependencies and openPASS.

openPASS can be build using a conanfile.txt. It holds every Information which is needed to build and install openPASS.

The following file shows an example which can be used. This example is also available in the conan folder in the simopenpass repository.

[requires]
   openpass/0.8

[generators]
   cmake

[imports]
   . , * -> C:/openpass @

The requires field describes what package with what version shall be installed. It´s also possible to add more packages here or change the version.

The generator field is used to add different generators to the process. In this example the cmake generator would generate cmake files, which describe where to find the openPASS in the local cache. There are also other possibilities like a cmake_find_package generator, which generates cmake FindPackage files.

At this point openPASS only exists in the local cache of Conan. With the imports field it´s possible to specify where and how the binaries shall be copied from the local cache to the user space. The example follows the following pattern:

<source>, <pattern> -> <destination>

Note

It is possible to add several lines for more specific copying operations. Also there are more field available than this simple example shows. See Conan Docs for additional information.

Conan can simply install openPASS with the following command. If the dependencies or openPASS were not build in any previous step, the binaries will not be available in the local cache of Conan. Conan can build them by adding --build=missing to the following command.

conan install <path to conanfile.txt>

Build only ThirdParties

The ThirdParty libraries can be build and installed the same way.

[requires]
   OSI/3.3.1
   FMILibrary/2.0.3

[generators]
   cmake_find_package
   cmake_paths

[imports]
   . , * -> C:/openpass/ThirdParty @