[question] tools.build.build_jobs can not parse conf.tools.build:jobs

When using Conan conf to extract build:jobs based on os.cpu_count(), Conan fails due an unexpected type, it wanted int, but received string.

This feature it’s documented on Docs:

https://docs.conan.io/en/latest/reference/config_files/global_conf.html#configuration-file-template

https://docs.conan.io/en/latest/reference/conanfile/tools/build.html#conan-tools-build-build-jobs

Related to https://github.com/conan-io/conan-center-index/issues/12737

/cc @blockspacer

Environment Details (include every applicable attribute)

• Operating System+version: OSX
• Compiler+version: N/A
• Conan version: 1.52.0
• Python version: 3.10

Steps to reproduce (Include if Applicable)

from conan import ConanFile
from conan.tools.build import build_jobs

class FooConan(ConanFile):
    def configure(self):
        cpucount = build_jobs(self)
        self.output.info(f"**** CPUCOUNT: {type(cpucount)}")
        self.output.info(f"**** CPUCOUNT: {cpucount}")

conan profile update 'conf.tools.build:jobs={{os.cpu_count()}}' default 
conan create . foo/0.1@  -pr:b=default -pr:h=default

Logs (Executed commands with output) (Include/Attach if Applicable)

foo/0.1: Exported revision: e32b23a17d67db859472a46a6ceb3e0b
Configuration (profile_host):
[settings]
arch=armv8
arch_build=armv8
build_type=Release
compiler=apple-clang
compiler.libcxx=libc++
compiler.version=13
os=Macos
os_build=Macos
[options]
[build_requires]
[env]
[conf]
tools.build:jobs={{os.cpu_count()}}

Configuration (profile_build):
[settings]
arch=armv8
arch_build=armv8
build_type=Release
compiler=apple-clang
compiler.libcxx=libc++
compiler.version=13
os=Macos
os_build=Macos
[options]
[build_requires]
[env]
[conf]
tools.build:jobs={{os.cpu_count()}}

ERROR: Traceback (most recent call last):
  File "/Users/uilian/.pyenv/versions/3.10.4/lib/python3.10/site-packages/conans/errors.py", line 34, in conanfile_exception_formatter
    yield
  File "/Users/uilian/.pyenv/versions/3.10.4/lib/python3.10/site-packages/conans/client/conanfile/configure.py", line 27, in run_configure_method
    conanfile.configure()
  File "/Users/uilian/.conan/data/foo/0.1/_/_/export/conanfile.py", line 10, in configure
    cpucount = build_jobs(self)
  File "/Users/uilian/.pyenv/versions/3.10.4/lib/python3.10/site-packages/conan/tools/build/cpu.py", line 9, in build_jobs
    njobs = conanfile.conf.get("tools.build:jobs",
  File "/Users/uilian/.pyenv/versions/3.10.4/lib/python3.10/site-packages/conans/model/conf.py", line 246, in get
    raise ConanException("[conf] {name} must be a {type}-like object. "
conans.errors.ConanException: [conf] tools.build:jobs must be a int-like object. The value '{{os.cpu_count()}}' introduced is a str object

[blockspacer]

Thanks, ill try to use myprofile.jinja

BTW, it may be good idea to link https://docs.conan.io/en/latest/reference/profiles.html#profile-templates near info about global.conf in documentation.

[memsharded]

Hi @blockspacer

yes, sorry I failed to properly explain. I mean the file extension. You need to opt-in using something like myprofile.jinja (this will not be necessary in 2.0, but it was necessary in 1.X to avoid breaking).

The docs are in https://docs.conan.io/en/latest/reference/profiles.html#profile-templates