How to capture package version from text or build files¶
It is common that a library version number would be already encoded in a text file, in some build scripts, etc. Lets take as an example that we have the following library layout, that we want to create a package from it:
conanfile.py CMakeLists.txt src hello.cpp ...
The CMakeLists.txt will have some variables to define the library version number. Lets assume for simplicity that it has some line like:
cmake_minimum_required(VERSION 2.8) set(MY_LIBRARY_VERSION 1.2.3) # This is the version we want add_library(hello src/hello.cpp)
We will typically have in our conanfile.py package recipe:
class HelloConan(ConanFile): name = "Hello" version = "1.2.3"
Usually this takes very little maintenance, and when the CMakeLists version is bumped, the conanfile.py version is bumped too. But if you want to only have to update the CMakeLists.txt version, you can extract the version dynamically, with:
from conans import ConanFile from conans.tools import load import re def get_version(): try: content = load("CMakeLists.txt") version = re.search(b"set\(MY_LIBRARY_VERSION (.*)\)", content).group(1) return version.strip() except Exception as e: return None class HelloConan(ConanFile): name = "Hello" version = get_version()
Even if the CMakeLists.txt file is not exported to the local cache, it will still work, as the
get_version() function returns None
when it is not found, then taking the version number from the package metadata (layout).