Custom Conan generators

In the case that you need to use a build system or tool that is not supported by Conan off-the-shelf, you could create your own custom integrations using a custom generator. This can be done in two different ways.

Custom generators as python_requires

One way of having your own custom generators in Conan is by using them as python_requires. You could declare a MyGenerator class with all the logic to generate some files inside the mygenerator/1.0 python_requires package:

mygenerator/conanfile.py

from conan import ConanFile
from conan.tools.files import save


class MyGenerator:
    def __init__(self, conanfile):
        self._conanfile = conanfile

    def generate(self):
        deps_info = ""
        for dep, _ in self._conanfile.dependencies.items():
            deps_info += f"{dep.ref.name}, {dep.ref.version}\n"
        save(self._conanfile, "deps.txt", deps_info)


class PyReq(ConanFile):
    name = "mygenerator"
    version = "1.0"
    package_type = "python-require"

And then conan create mygenerator and use it in the generate method of your own packages like this:

pkg/conanfile.py

from conan import ConanFile


class MyPkg(ConanFile):
    name = "pkg"
    version = "1.0"

    python_requires = "mygenerator/1.0"
    requires = "zlib/1.2.11", "bzip2/1.0.8"

    def generate(self):
        mygenerator = self.python_requires["mygenerator"].module.MyGenerator(self)
        mygenerator.generate()

Then, doing a conan install pkg on this pkg recipe, will create a deps.txt text file containing:

zlib, 1.2.11
bzip2, 1.0.8

This has the advantage that you can version your own custom generators as packages and also that you can share those generators as Conan packages.

Using global custom generators

You can also use your custom generators globally if you store them in the [CONAN_HOME]/extensions/generators folder. You can place them directly in that folder or install with the conan config install command.

[CONAN_HOME]/extensions/generators/mygen.py

from conan.tools.files import save


class MyGenerator:
    def __init__(self, conanfile):
        self._conanfile = conanfile

    def generate(self):
        deps_info = ""
        for dep, _ in self._conanfile.dependencies.items():
            deps_info = f"{dep.ref.name}, {dep.ref.version}"
        save(self._conanfile, "deps.txt", deps_info)

Then you can use them by name in the recipes or in the command line using the -g argument:

conan install --requires=zlib/1.2.13 -g MyGenerator