source: general/prog/python3.xml@ 55af6ce

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../../general.ent">
  %general-entities;

  <!ENTITY python3-download-http
           "https://www.python.org/ftp/python/&python3-version;/Python-&python3-version;.tar.xz">
  <!ENTITY python3-download-ftp  " ">
  <!ENTITY python3-md5sum        "8defb33f0c37aa4bdd3a38ba52abde4e">
  <!ENTITY python3-size          "20 MB">
  <!ENTITY python3-buildsize     "335 MB (add 57 MB for tests)">
  <!ENTITY python3-time          "2.2 SBU (add 1.0 SBU for tests; both using parallelism=4)">
  <!--
  Note: Size does not reflect docs that were installed in LFS.
  -->
  <!ENTITY python3htmldoc-download-http
  "https://www.python.org/ftp/python/doc/&python3-version;/python-&python3-version;-docs-html.tar.bz2">
  <!ENTITY python3-docs-md5sum "6025ee63c0ded34aac874f5da8f1a90c" >
]>

<sect1 id="python3" xreflabel="Python-&python3-version;">
  <?dbhtml filename="python3.html" ?>


  <title>Python-&python3-version;</title>

  <indexterm zone="python3">
    <primary sortas="a-Python3">Python3</primary>
  </indexterm>

  <sect2 role="package">
    <title>Introduction to Python 3</title>

    <para>
      The <application>Python 3</application> package contains the
      <application>Python</application> development environment.
      This is useful for object-oriented programming, writing scripts,
      prototyping large programs or developing entire applications.
    </para>

    <note>
      <para>
        <application>Python 3</application> was installed in LFS.
        The only reason to rebuild it here is if optional modules
        are needed, or to upgrade this package.
      </para>
    </note>

    &lfs121_checked;

    <important>
      <para>
         If upgrading to a new Python-3 minor version (for example,
         from Python-3.11.x to Python-3.12.0), you will need to reinstall
         any Python3 modules you have installed.  You should also
         reinstall packages that generate Python3 modules
         including
         &gobject-introspection;,
         <xref linkend="libxml2"/>,
         <xref linkend="opencv"/>,
         <xref linkend="fontforge"/>,
         <xref linkend="gnome-tweaks"/>,
         <xref linkend="samba"/>, and
         <xref linkend="graphviz"/> (if swig is installed).
      </para>

      <para>Before you upgrade, you can get a list of modules installed
        with <command>pip3 list</command>.  The list may be incomplete as
        some Python modules are not installed with <command>pip3</command>,
        for example the <literal>cracklib</literal> module installed by
        <xref role='nodep' linkend='cracklib'/>.  Use <command>ls
        /usr/lib/python3.<replaceable>minor</replaceable>/site-packages</command>
        for a comprehensive list.
      </para>

      <para>
         The Python modules from LFS will also have to be reinstalled:
         <ulink url="&lfs-root;/chapter08/flit-core.html">flit-core</ulink>,
         <ulink url="&lfs-root;/chapter08/wheel.html">wheel</ulink>,
         <ulink url="&lfs-root;/chapter08/setuptools.html">setuptools</ulink>,
         <ulink url="&lfs-root;/chapter08/meson.html">meson</ulink>,
         <ulink url="&lfs-root;/chapter08/markupsafe.html">MarkupSafe</ulink>,
         and <ulink url="&lfs-root;/chapter08/jinja2.html">Jinja2</ulink>.
      </para>
    </important>

    <bridgehead renderas="sect3">Package Information</bridgehead>
    <itemizedlist spacing="compact">
      <listitem>
        <para>
          Download (HTTP): <ulink url="&python3-download-http;"/>
        </para>
      </listitem>
      <listitem>
        <para>
          Download (FTP): <ulink url="&python3-download-ftp;"/>
        </para>
      </listitem>
      <listitem>
        <para>
          Download MD5 sum: &python3-md5sum;
        </para>
      </listitem>
      <listitem>
        <para>
          Download size: &python3-size;
        </para>
      </listitem>
      <listitem>
        <para>
          Estimated disk space required: &python3-buildsize;
        </para>
      </listitem>
      <listitem>
        <para>
          Estimated build time: &python3-time;
        </para>
      </listitem>
    </itemizedlist>

    <bridgehead renderas="sect3">Additional Optional Download</bridgehead>
    <itemizedlist spacing="compact">
      <listitem>
        <para>
          Download (HTTP): <ulink url="&python3htmldoc-download-http;"/>
        </para>
      </listitem>
      <listitem>
        <para>
          Download MD5 sum: &python3-docs-md5sum;
        </para>
      </listitem>
    </itemizedlist>

    <bridgehead renderas="sect3">Python 3 Dependencies</bridgehead>

    <bridgehead renderas="sect4">Recommended</bridgehead>
    <para role="recommended">
      <xref linkend="sqlite"/> (required if building firefox or thunderbird)
    </para>

    <bridgehead renderas="sect4">Optional</bridgehead>
    <para role="optional">
      <xref linkend="bluez"/>,
      <xref linkend="gdb"/> (required for some tests),
      <xref linkend="valgrind"/>, and
      <ulink url="https://www.bytereef.org/mpdecimal/">libmpdec</ulink>
    </para>

    <bridgehead renderas="sect4">Optional (For Additional Modules)</bridgehead>
    <para role="optional">
      <xref linkend="libnsl"/>, 
      <xref linkend="tk"/>, and
      &berkeley-db;
    </para>

    <para condition="html" role="usernotes">Editor Notes:
      <ulink url="&blfs-wiki;/Python3"/>
    </para>
  </sect2>

  <sect2 role="installation">
    <title>Installation of Python 3</title>

    <para>
      Install <application>Python 3</application> by running the following
      commands:
    </para>

<screen><userinput>CXX="/usr/bin/g++"               \
./configure --prefix=/usr        \
            --enable-shared      \
            --with-system-expat  \
            --enable-optimizations &amp;&amp;
make</userinput></screen>

    <para>
      <!-- I'm getting a test failure with empty $LANG:
           "test test_curses failed"
           "_curses.error: inswstr() returned ERR"
           not sure why, but let's just work around it with LC_ALL.  
  
           For Python-3.12.0 all tests pass with only LANG=en_US.utf8.
           Total tests: run=41,505 skipped=1,199
           Total test files: run=477/483 skipped=12 resource_denied=6

           For Python-3.12.1 all tests pass
           Total tests: run=40,624 skipped=1,136
           Total test files: run=486/489 skipped=24 resource_denied=3

           For Python-3.12.2 all tests pass
           Total tests: run=41,580 skipped=1,144
           Total test files: run=485/488 skipped=23 resource_denied=3

           For Python-3.12.3 all tests pass
           Total tests: run=41,778 skipped=1,155
           Total test files: run=485/488 skipped=24 resource_denied=3
      -->
      To test the result, issue <command>LC_ALL=en_US.UTF-8
      make test</command>.
      Some tests may need an Internet connection.
    </para>

    <para>
      Now, as the <systemitem class="username">root</systemitem> user:
    </para>

<screen role="root"><userinput>make install</userinput></screen>

    <para>
      If upgrading and the documentation has been downloaded, optionally install
      it as the &root; user:
    </para>

<screen role="root"><userinput>install -v -dm755 /usr/share/doc/python-&python3-version;/html

tar --strip-components=1  \
    --no-same-owner       \
    --no-same-permissions \
    -C /usr/share/doc/python-&python3-version;/html \
    -xvf ../python-&python3-version;-docs-html.tar.bz2</userinput></screen>

  </sect2>

  <sect2 role="commands">
    <title>Command Explanations</title>

    <para>
      <command> CXX="/usr/bin/g++" ./configure ...</command>: Avoid an annoying
      message during configuration.
    </para>

    <para>
      <parameter>--with-system-expat</parameter>: This switch enables linking
      against the system version of <application>Expat</application>.
    </para>

<!--
    <para>
      <parameter>- -with-ensurepip=yes</parameter> : This switch enables building
      the <command>pip</command> and <command>setuptools</command> packaging
      programs. <command>setuptools</command> is needed for building some
      Python modules.
    </para>
-->
    <para>
      <option>--with-dbmliborder=bdb:gdbm:ndbm</option>: Use this switch
      if you want to build the <application>Python</application> DBM Module
      against <application>Berkeley DB</application> instead of
      <application>GDBM</application>.
    </para>

    <para>
      <parameter>--enable-optimizations</parameter>: This switch enables
      stable, but expensive, optimizations.
    </para>

    <para>
      <option>--with-lto</option>: This optional switch enables thick Link
      Time Optimization. Unusually, it creates a much larger <filename
      class="libraryfile">/usr/lib/python&python3-majorver;/config-&python3-majorver;-&lt;arch&gt;-linux-gnu/libpython&python3-majorver;.a</filename>
      with a small increase in the time to compile
      <application>Python</application>. Run-time results do not appear to show
      any benefit from doing this.
    </para>

  </sect2>

  <sect2 role="configuration">
    <title>Configuring Python 3</title>

    <para>
      In order for <command>python3</command> to find the installed
      documentation, create the following version independent symlink:
    </para>

<screen role="root"><userinput>ln -svfn python-&python3-version; /usr/share/doc/python-3</userinput></screen>

    <para>
      and add the following environment variable to the individual user's or
      system's profile:
    </para>

<screen role="root"><userinput>export PYTHONDOCS=/usr/share/doc/python-3/html</userinput></screen>

  </sect2>

  <sect2 role="content">
    <title>Contents</title>

    <segmentedlist>
      <segtitle>Installed Programs</segtitle>
      <segtitle>Installed Libraries</segtitle>
      <segtitle>Installed Directories</segtitle>

      <seglistitem>
        <seg>
          2to3 (symlink) and
          2to3-&python3-majorver;,

          <!--
          easy_install-&python3-majorver;,
          -->

          idle3 (symlink) and
          idle&python3-majorver;,

          pip3 and
          pip&python3-majorver;,

          pydoc3 (symlink) and
          pydoc&python3-majorver;,

          python3 (symlink) and
          python&python3-majorver;, and

          python3-config (symlink) and
          python&python3-majorver;-config
        </seg>
        <seg>
          libpython&python3-majorver;.so and libpython3.so
        </seg>
        <seg>
          /usr/include/python&python3-majorver;,
          /usr/lib/python&python3-majorver;, and
          /usr/share/doc/python-&python3-version;
        </seg>
      </seglistitem>
    </segmentedlist>

    <variablelist>
      <bridgehead renderas="sect3">Short Descriptions</bridgehead>
      <?dbfo list-presentation="list"?>
      <?dbhtml list-presentation="table"?>
      <!--
      <varlistentry id="2to3">
        <term><command>2to3</command></term>
        <listitem>
          <para>
            is designed to assist in the transition between python2 and python3
            by automatically converting code to be Python3 compatible.
          </para>
          <indexterm zone="python3 2to3">
            <primary sortas="b-2to3">2to3</primary>
          </indexterm>
        </listitem>
      </varlistentry>
      Put here for easy use when removing Python2 -->
      <!--
      <varlistentry id="easy_install">
        <term><command>easy_install</command></term>
        <listitem>
          <para>
            is a frontend to pip3 to make it easier to configure python modules
            through the PIP package manager
          </para>
          <indexterm zone="python3 easy_install">
            <primary sortas="python3 easy_install">easy_install</primary>
          </indexterm>
        </listitem>
      </varlistentry>
      -->
      <varlistentry id="idle3">
        <term><command>idle3</command></term>
        <listitem>
          <para>
            is a wrapper script that opens a <application>Python</application>
            aware GUI editor. For this script to run, you must have installed
            <application>Tk</application> before Python so that the Tkinter
            Python module is built
          </para>
          <indexterm zone="python3 idle3">
            <primary sortas="b-idle3">idle3</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="pydoc3">
        <term><command>pydoc3</command></term>
        <listitem>
          <para>
            is the <application>Python</application> documentation
            tool
          </para>
          <indexterm zone="python3 pydoc3">
            <primary sortas="b-pydoc3">pydo3c</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="python3-prog">
        <term><command>python3</command></term>
        <listitem>
          <para>
            is an interpreted, interactive, object-oriented programming
            language
          </para>
          <indexterm zone="python3 python3-prog">
            <primary sortas="b-python3">python3</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="python-ver">
        <term><command>python&python3-majorver;</command></term>
        <listitem>
          <para>
            is a version-specific name for the <command>python</command>
            program
          </para>
          <indexterm zone="python3 python-ver">
            <primary sortas="b-python&python3-majorver;">python&python3-majorver;</primary>
          </indexterm>
        </listitem>
      </varlistentry>
      <!--
      <varlistentry id="pyvenv">
        <term><command>pyvenv</command></term>
        <listitem>
          <para>
            creates virtual <application>Python</application> environments in
            one or more target directories.
          </para>
          <indexterm zone="python3 pyvenv">
            <primary
            sortas="b-python&python3-majorver;">python&python3-majorver;</primary>
          </indexterm>
        </listitem>
      </varlistentry>
      -->
    </variablelist>

  </sect2>

</sect1>