The Python 3 package contains the Python development environment.
It is useful for object-oriented programming, writing scripts,
prototyping large programs, or developing entire applications.
Approximate build time:
3.4 SBU
Required disk space:
283 MB
8.50.1. Installation of Python 3
Prepare Python for compilation:
./configure --prefix=/usr \
--enable-shared \
--with-system-expat \
--with-system-ffi \
--enable-optimizations
The meaning of the configure options:
-
--with-system-expat
-
This switch enables linking against system version of
Expat.
-
--with-system-ffi
-
This switch enables linking against system version of
libffi.
-
--enable-optimizations
-
This switch enables stable, but expensive, optimizations.
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
In several places we use the pip3 command to install Python 3
programs and modules for all users as root. This conflicts with the Python developers
recommendation to install packages into a virtual environment or
the home directory of a regular user (by running pip3 as this user). To this end,
a multi-line warning is written when using pip3 as the root user. The main reason of this
recommendation is for avoiding a conflict with the system package
manager (dpkg for
example), but LFS does not have a system-wide package manager so
this is not a problem. And, pip3 will attempt to check for a
new version of itself whenever it's run. As domain name resolving
is not configured yet in LFS chroot environment, it will fail to
check for a new version and produce a warning. Once we boot the LFS
system and set up network connection, it will then produce a
warning telling the user to update it from a pre-built wheel on
PyPI if any new version is available. But LFS consider pip3 a part of Python 3 so it
should not be updated separately, and an update from a pre-built
wheel will deviate from our purpose to build a Linux system from
source code. So the warning for a new pip3 version should be ignored as
well. If desired, suppress these warnings by running the following
commands:
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 take care that the pip3
install commands in both the books should be run
as the root user unless it's for
a Python virtual environment. Running a pip3 install as a
non-root user may seem to work
fine, but it will cause the installed module to be inaccessible
by other users.
pip3 install will
not reinstall an already installed module by default. For 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-3.10.6/html
tar --strip-components=1 \
--no-same-owner \
--no-same-permissions \
-C /usr/share/doc/python-3.10.6/html \
-xvf ../python-3.10.6-docs-html.tar.bz2
The meaning of the documentation install
commands:
-
--no-same-owner
and --no-same-permissions
-
Ensure the installed files have the correct ownership and
permissions. Without these options, using tar will install the package files with
the upstream creator's values.