8.51.1. Installation of Python 3
Prepare Python for compilation:
./configure --prefix=/usr \
--enable-shared \
--with-system-expat \
--enable-optimizations
The meaning of the configure options:
-
--with-system-expat
-
This switch enables linking against the system version of
Expat.
-
--enable-optimizations
-
This switch enables extensive, but time-consuming,
optimization steps. The interpreter is built twice; tests
performed on the first build are used to improve the
optimized final version.
Compile the package:
make
Running the tests at this point is not recommended. The tests are
known to hang indefinitely in the partial LFS environment. If
desired, the tests can be rerun at the end of this chapter, or when
Python 3 is reinstalled in BLFS. To run the tests anyway, issue
make test.
Install the package:
make install
We use the pip3
command to install Python 3 programs and modules for all users as
root in several places in this
book. This conflicts with the Python developers' recommendation: to
install packages into a virtual environment, or into the home
directory of a regular user (by running pip3 as this user). A multi-line
warning is triggered whenever pip3 is issued by the
root user.
The main reason for the recommendation is to avoid conflicts with
the system's package manager (dpkg, for example). LFS does not
have a system-wide package manager, so this is not a problem. Also,
pip3 will check for a
new version of itself whenever it's run. Since domain name
resolution is not yet configured in the LFS chroot environment,
pip3 cannot check for
a new version of itself, and will produce a warning.
After we boot the LFS system and set up a network connection, a
different warning will be issued, telling the user to update
pip3 from a pre-built
wheel on PyPI (whenever a new version is available). But LFS
considers pip3 to be
a part of Python 3, so it should not be updated separately. Also,
an update from a pre-built wheel would deviate from our objective:
to build a Linux system from source code. So the warning about a
new version of pip3
should be ignored as well. If you wish, you can suppress all these
warnings by running the following command, which creates a
configuration file:
cat > /etc/pip.conf << EOF
[global]
root-user-action = ignore
disable-pip-version-check = true
EOF
![[Important]](../images/important.png)
Important
In LFS and BLFS we normally build and install Python modules with
the pip3 command.
Please be sure that the pip3
install commands in both books are run as the
root user (unless it's for a
Python virtual environment). Running pip3 install as a
non-root user may seem to work,
but it will cause the installed module to be inaccessible by
other users.
pip3 install will
not reinstall an already installed module automatically. When
using the pip3
install command to upgrade a module (for example,
from meson-0.61.3 to meson-0.62.0), insert the option --upgrade into the command line. If
it's really necessary to downgrade a module, or reinstall the
same version for some reason, insert --force-reinstall --no-deps into
the command line.
If desired, install the preformatted documentation:
install -v -dm755 /usr/share/doc/python-3.12.1/html
tar --no-same-owner \
-xvf ../python-3.12.1-docs-html.tar.bz2
cp -R --no-preserve=mode python-3.12.1-docs-html/* \
/usr/share/doc/python-3.12.1/html
The meaning of the documentation install
commands:
-
--no-same-owner
(tar) and --no-preserve=mode
(cp)
-
Ensure the installed files have the correct ownership and
permissions. Without these options, tar will install the package files with
the upstream creator's values and files would have
restrictive permissions.