It is possible to reuse python code existing in other conanfile.py recipes with the
functionality, doing something like:
from conans import ConanFile class Pkg(ConanFile): python_requires = "pyreq/0.1@user/channel" def build(self): v = self.python_requires["pyreq"].module.myvar # myvar defined in pyreq's conanfile.py f = self.python_requires["pyreq"].module.myfunct() # myfunct defined in pyreq's conanfile.py self.output.info("%s,%s" % (v, f))
See this section: Python requires: reusing python code in recipes
Output and Running¶
Use the self.output to print contents to the output.
self.output.success("This is a good, should be green") self.output.info("This is a neutral, should be white") self.output.warn("This is a warning, should be yellow") self.output.error("Error, should be red") self.output.rewrite_line("for progress bars, issues a cr")
Check the source code. You might be able to produce different outputs with different colors.
run(self, command, output=True, cwd=None, win_bash=False, subsystem=None, msys_mingw=True, ignore_errors=False, run_environment=False, with_login=True, env="conanbuild"):
self.run() is a helper to run system commands and throw exceptions when errors occur,
so that command errors do not pass unnoticed. It is just a wrapper for
When the environment variable
CONAN_PRINT_RUN_COMMANDS is set to true (or its equivalent
print_run_commands conan.conf configuration variable, under
[general]) then all the
self.run() will print to output the command to be executed.
command can be specified as a string which is passed to the system shell.
Alternatively it can be specified as a sequence of strings, the first of which is
interpreted as the name of the program to be executed and the remaining ones are passed as
arguments. Unless you are relying on shell-specific features such as redirection or command
substitution, providing a sequence of strings is generally preferred as it allows Conan to
take care of any required escaping and quoting of arguments (e.g. to permit spaces in file
- output (Optional, Defaulted to
True) When True it will write in stdout.
You can pass any stream that accepts a
writemethod like a
from six import StringIO # Python 2 and 3 compatible mybuf = StringIO() self.run("mycommand", output=mybuf) self.output.warn(mybuf.getvalue())
- output (Optional, Defaulted to
cwd (Optional, Defaulted to
.current directory): Current directory to run the command.
win_bash (Optional, Defaulted to
False): When True, it will run the configure/make commands inside a bash.
subsystem (Optional, Defaulted to
Nonewill autodetect the subsystem): Used to escape the command according to the specified subsystem.
msys_mingw (Optional, Defaulted to
True) If the specified subsystem is MSYS2, will start it in MinGW mode (native windows development).
ignore_errors (Optional, Defaulted to
False). This method raises an exception if the command fails. If
ignore_errors=True, it will not raise an exception. Instead, the user can use the return code to check for errors.
run_environment (Optional, Defaulted to
False). Applies a
RunEnvironment, so the environment variables PATH, LD_LIBRARY_PATH and DYLIB_LIBRARY_PATH are defined in the command execution adding the values of the “lib” and “bin” folders of the dependencies. Allows executables to be easily run using shared libraries from its dependencies.
with_login (Optional, Defaulted to
True): Pass the
--loginflag to bash command when using
win_bashparameter. This might come handy when you don’t want to create a fresh user session for running the command.
env (Optional, Defaulted to
conanbuild): the environment or list of environment activations scripts to pre-pend to the given
None, no environment will be pre-pended.
Requiring a Conan version for the recipe¶
Available since: 1.28.0
A required Conan version can be declared in the conanfile.py using
throw an error when the Conan version installed does not meet the criteria established by the
variable. To add
required_conan_version to a conanfile.py just declare it before the recipe
from conans import ConanFile required_conan_version = ">=1.27.1" class Pkg(ConanFile): settings = "os", "compiler", "arch", "build_type" ...
It is also possible to declare
required_conan_version at configuration level for the whole client
adding it to the conan.conf file.