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8615d47a3a
Fixes [YOCTO #12399] The bug was to get the BitBake User Manual into the YP Mega-manual. All the changes here create unique tags used with variables in the BitBake Manual. Prior to the fix, tags were identical between like variables in the YP reference manual and the BitBake User Manual. The reason for this is because when I created the BitBake manual's glossary, it was a cut-and-paste operation to get the bulk of the work started. At the time, the BitBake User Manual was not a part of the Mega-manual. Once we decided to include the BitBake User Manual as part of the Mega-Manual, building the mega-manual produced warnings for all these duplicate links. To fix, I have updated the variable tags in the BitBake User Manual to use the following form: 'var-bb-<variable_name>' The tags used in the YP ref-manual follow this form (original): 'var-<variable_name>' (Bitbake rev: fb6de2057aae3fbdf37f007d2e47794b332020e1) Signed-off-by: Scott Rifenbark <srifenbark@gmail.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
895 lines
45 KiB
XML
895 lines
45 KiB
XML
<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<chapter id="bitbake-user-manual-intro">
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<title>Overview</title>
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<para>
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Welcome to the BitBake User Manual.
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This manual provides information on the BitBake tool.
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The information attempts to be as independent as possible regarding
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systems that use BitBake, such as OpenEmbedded and the
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Yocto Project.
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In some cases, scenarios or examples within the context of
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a build system are used in the manual to help with understanding.
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For these cases, the manual clearly states the context.
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</para>
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<section id="intro">
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<title>Introduction</title>
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<para>
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Fundamentally, BitBake is a generic task execution
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engine that allows shell and Python tasks to be run
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efficiently and in parallel while working within
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complex inter-task dependency constraints.
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One of BitBake's main users, OpenEmbedded, takes this core
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and builds embedded Linux software stacks using
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a task-oriented approach.
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</para>
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<para>
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Conceptually, BitBake is similar to GNU Make in
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some regards but has significant differences:
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<itemizedlist>
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<listitem><para>
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BitBake executes tasks according to provided
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metadata that builds up the tasks.
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Metadata is stored in recipe (<filename>.bb</filename>)
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and related recipe "append" (<filename>.bbappend</filename>)
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files, configuration (<filename>.conf</filename>) and
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underlying include (<filename>.inc</filename>) files, and
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in class (<filename>.bbclass</filename>) files.
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The metadata provides
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BitBake with instructions on what tasks to run and
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the dependencies between those tasks.
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</para></listitem>
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<listitem><para>
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BitBake includes a fetcher library for obtaining source
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code from various places such as local files, source control
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systems, or websites.
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</para></listitem>
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<listitem><para>
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The instructions for each unit to be built (e.g. a piece
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of software) are known as "recipe" files and
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contain all the information about the unit
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(dependencies, source file locations, checksums, description
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and so on).
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</para></listitem>
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<listitem><para>
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BitBake includes a client/server abstraction and can
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be used from a command line or used as a service over
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XML-RPC and has several different user interfaces.
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</para></listitem>
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</itemizedlist>
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</para>
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</section>
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<section id="history-and-goals">
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<title>History and Goals</title>
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<para>
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BitBake was originally a part of the OpenEmbedded project.
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It was inspired by the Portage package management system
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used by the Gentoo Linux distribution.
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On December 7, 2004, OpenEmbedded project team member
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Chris Larson split the project into two distinct pieces:
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<itemizedlist>
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<listitem><para>BitBake, a generic task executor</para></listitem>
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<listitem><para>OpenEmbedded, a metadata set utilized by
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BitBake</para></listitem>
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</itemizedlist>
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Today, BitBake is the primary basis of the
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<ulink url="http://www.openembedded.org/">OpenEmbedded</ulink>
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project, which is being used to build and maintain Linux
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distributions such as the
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<ulink url='http://www.angstrom-distribution.org/'>Angstrom Distribution</ulink>,
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and which is also being used as the build tool for Linux projects
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such as the
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<ulink url='http://www.yoctoproject.org'>Yocto Project</ulink>.
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</para>
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<para>
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Prior to BitBake, no other build tool adequately met the needs of
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an aspiring embedded Linux distribution.
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All of the build systems used by traditional desktop Linux
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distributions lacked important functionality, and none of the
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ad hoc Buildroot-based systems, prevalent in the
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embedded space, were scalable or maintainable.
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</para>
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<para>
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Some important original goals for BitBake were:
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<itemizedlist>
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<listitem><para>
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Handle cross-compilation.
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</para></listitem>
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<listitem><para>
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Handle inter-package dependencies (build time on
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target architecture, build time on native
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architecture, and runtime).
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</para></listitem>
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<listitem><para>
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Support running any number of tasks within a given
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package, including, but not limited to, fetching
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upstream sources, unpacking them, patching them,
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configuring them, and so forth.
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</para></listitem>
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<listitem><para>
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Be Linux distribution agnostic for both build and
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target systems.
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</para></listitem>
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<listitem><para>
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Be architecture agnostic.
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</para></listitem>
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<listitem><para>
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Support multiple build and target operating systems
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(e.g. Cygwin, the BSDs, and so forth).
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</para></listitem>
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<listitem><para>
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Be self contained, rather than tightly
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integrated into the build machine's root
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filesystem.
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</para></listitem>
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<listitem><para>
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Handle conditional metadata on the target architecture,
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operating system, distribution, and machine.
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</para></listitem>
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<listitem><para>
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Be easy to use the tools to supply local metadata and packages
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against which to operate.
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</para></listitem>
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<listitem><para>
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Be easy to use BitBake to collaborate between multiple
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projects for their builds.
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</para></listitem>
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<listitem><para>
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Provide an inheritance mechanism to share
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common metadata between many packages.
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</para></listitem>
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</itemizedlist>
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Over time it became apparent that some further requirements
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were necessary:
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<itemizedlist>
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<listitem><para>
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Handle variants of a base recipe (e.g. native, sdk,
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and multilib).
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</para></listitem>
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<listitem><para>
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Split metadata into layers and allow layers
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to enhance or override other layers.
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</para></listitem>
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<listitem><para>
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Allow representation of a given set of input variables
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to a task as a checksum.
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Based on that checksum, allow acceleration of builds
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with prebuilt components.
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</para></listitem>
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</itemizedlist>
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BitBake satisfies all the original requirements and many more
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with extensions being made to the basic functionality to
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reflect the additional requirements.
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Flexibility and power have always been the priorities.
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BitBake is highly extensible and supports embedded Python code and
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execution of any arbitrary tasks.
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</para>
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</section>
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<section id="Concepts">
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<title>Concepts</title>
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<para>
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BitBake is a program written in the Python language.
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At the highest level, BitBake interprets metadata, decides
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what tasks are required to run, and executes those tasks.
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Similar to GNU Make, BitBake controls how software is
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built.
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GNU Make achieves its control through "makefiles", while
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BitBake uses "recipes".
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</para>
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<para>
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BitBake extends the capabilities of a simple
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tool like GNU Make by allowing for the definition of much more
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complex tasks, such as assembling entire embedded Linux
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distributions.
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</para>
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<para>
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The remainder of this section introduces several concepts
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that should be understood in order to better leverage
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the power of BitBake.
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</para>
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<section id='recipes'>
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<title>Recipes</title>
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<para>
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BitBake Recipes, which are denoted by the file extension
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<filename>.bb</filename>, are the most basic metadata files.
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These recipe files provide BitBake with the following:
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<itemizedlist>
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<listitem><para>Descriptive information about the
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package (author, homepage, license, and so on)</para></listitem>
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<listitem><para>The version of the recipe</para></listitem>
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<listitem><para>Existing dependencies (both build
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and runtime dependencies)</para></listitem>
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<listitem><para>Where the source code resides and
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how to fetch it</para></listitem>
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<listitem><para>Whether the source code requires
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any patches, where to find them, and how to apply
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them</para></listitem>
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<listitem><para>How to configure and compile the
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source code</para></listitem>
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<listitem><para>Where on the target machine to install the
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package or packages created</para></listitem>
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</itemizedlist>
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</para>
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<para>
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Within the context of BitBake, or any project utilizing BitBake
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as its build system, files with the <filename>.bb</filename>
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extension are referred to as recipes.
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<note>
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The term "package" is also commonly used to describe recipes.
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However, since the same word is used to describe packaged
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output from a project, it is best to maintain a single
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descriptive term - "recipes".
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Put another way, a single "recipe" file is quite capable
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of generating a number of related but separately installable
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"packages".
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In fact, that ability is fairly common.
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</note>
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</para>
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</section>
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<section id='configuration-files'>
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<title>Configuration Files</title>
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<para>
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Configuration files, which are denoted by the
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<filename>.conf</filename> extension, define
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various configuration variables that govern the project's build
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process.
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These files fall into several areas that define
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machine configuration options, distribution configuration
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options, compiler tuning options, general common
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configuration options, and user configuration options.
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The main configuration file is the sample
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<filename>bitbake.conf</filename> file, which is
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located within the BitBake source tree
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<filename>conf</filename> directory.
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</para>
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</section>
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<section id='classes'>
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<title>Classes</title>
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<para>
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Class files, which are denoted by the
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<filename>.bbclass</filename> extension, contain
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information that is useful to share between metadata files.
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The BitBake source tree currently comes with one class metadata file
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called <filename>base.bbclass</filename>.
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You can find this file in the
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<filename>classes</filename> directory.
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The <filename>base.bbclass</filename> class files is special since it
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is always included automatically for all recipes
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and classes.
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This class contains definitions for standard basic tasks such
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as fetching, unpacking, configuring (empty by default),
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compiling (runs any Makefile present), installing (empty by
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default) and packaging (empty by default).
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These tasks are often overridden or extended by other classes
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added during the project development process.
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</para>
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</section>
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<section id='layers'>
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<title>Layers</title>
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<para>
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Layers allow you to isolate different types of
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customizations from each other.
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While you might find it tempting to keep everything in one layer
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when working on a single project, the more modular you organize
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your metadata, the easier it is to cope with future changes.
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</para>
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<para>
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To illustrate how you can use layers to keep things modular,
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consider customizations you might make to support a specific target machine.
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These types of customizations typically reside in a special layer,
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rather than a general layer, called a Board Support Package (BSP)
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Layer.
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Furthermore, the machine customizations should be isolated from
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recipes and metadata that support a new GUI environment, for
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example.
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This situation gives you a couple of layers: one for the machine
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configurations and one for the GUI environment.
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It is important to understand, however, that the BSP layer can still
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make machine-specific additions to recipes within
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the GUI environment layer without polluting the GUI layer itself
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with those machine-specific changes.
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You can accomplish this through a recipe that is a BitBake append
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(<filename>.bbappend</filename>) file.
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</para>
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</section>
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<section id='append-bbappend-files'>
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<title>Append Files</title>
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<para>
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Append files, which are files that have the
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<filename>.bbappend</filename> file extension, extend or
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override information in an existing recipe file.
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</para>
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<para>
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BitBake expects every append file to have a corresponding recipe file.
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Furthermore, the append file and corresponding recipe file
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must use the same root filename.
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The filenames can differ only in the file type suffix used
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(e.g. <filename>formfactor_0.0.bb</filename> and
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<filename>formfactor_0.0.bbappend</filename>).
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</para>
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<para>
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Information in append files extends or
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overrides the information in the underlying,
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similarly-named recipe files.
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</para>
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<para>
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When you name an append file, you can use the
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"<filename>%</filename>" wildcard character to allow for matching
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recipe names.
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For example, suppose you have an append file named
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as follows:
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<literallayout class='monospaced'>
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busybox_1.21.%.bbappend
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</literallayout>
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That append file would match any <filename>busybox_1.21.</filename><replaceable>x</replaceable><filename>.bb</filename>
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version of the recipe.
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So, the append file would match the following recipe names:
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<literallayout class='monospaced'>
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busybox_1.21.1.bb
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busybox_1.21.2.bb
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busybox_1.21.3.bb
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</literallayout>
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<note><title>Important</title>
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The use of the "<filename>%</filename>" character
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is limited in that it only works directly in front of the
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<filename>.bbappend</filename> portion of the append file's
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name.
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You cannot use the wildcard character in any other
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location of the name.
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</note>
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If the <filename>busybox</filename> recipe was updated to
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<filename>busybox_1.3.0.bb</filename>, the append name would not
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match.
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However, if you named the append file
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<filename>busybox_1.%.bbappend</filename>, then you would have a match.
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</para>
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<para>
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In the most general case, you could name the append file something as
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simple as <filename>busybox_%.bbappend</filename> to be entirely
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version independent.
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</para>
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</section>
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</section>
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<section id='obtaining-bitbake'>
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<title>Obtaining BitBake</title>
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<para>
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You can obtain BitBake several different ways:
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<itemizedlist>
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<listitem><para><emphasis>Cloning BitBake:</emphasis>
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Using Git to clone the BitBake source code repository
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is the recommended method for obtaining BitBake.
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Cloning the repository makes it easy to get bug fixes
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and have access to stable branches and the master
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branch.
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Once you have cloned BitBake, you should use
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the latest stable
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branch for development since the master branch is for
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BitBake development and might contain less stable changes.
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</para>
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<para>You usually need a version of BitBake
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that matches the metadata you are using.
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The metadata is generally backwards compatible but
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not forward compatible.</para>
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<para>Here is an example that clones the BitBake repository:
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<literallayout class='monospaced'>
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$ git clone git://git.openembedded.org/bitbake
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</literallayout>
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This command clones the BitBake Git repository into a
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directory called <filename>bitbake</filename>.
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Alternatively, you can
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designate a directory after the
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<filename>git clone</filename> command
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if you want to call the new directory something
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other than <filename>bitbake</filename>.
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Here is an example that names the directory
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<filename>bbdev</filename>:
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<literallayout class='monospaced'>
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$ git clone git://git.openembedded.org/bitbake bbdev
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</literallayout></para></listitem>
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<listitem><para><emphasis>Installation using your Distribution
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Package Management System:</emphasis>
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This method is not
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recommended because the BitBake version that is
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provided by your distribution, in most cases,
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is several
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releases behind a snapshot of the BitBake repository.
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</para></listitem>
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<listitem><para><emphasis>Taking a snapshot of BitBake:</emphasis>
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Downloading a snapshot of BitBake from the
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source code repository gives you access to a known
|
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branch or release of BitBake.
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<note>
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Cloning the Git repository, as described earlier,
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is the preferred method for getting BitBake.
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Cloning the repository makes it easier to update as
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patches are added to the stable branches.
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</note></para>
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<para>The following example downloads a snapshot of
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BitBake version 1.17.0:
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<literallayout class='monospaced'>
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$ wget http://git.openembedded.org/bitbake/snapshot/bitbake-1.17.0.tar.gz
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$ tar zxpvf bitbake-1.17.0.tar.gz
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</literallayout>
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After extraction of the tarball using the tar utility,
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you have a directory entitled
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<filename>bitbake-1.17.0</filename>.
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</para></listitem>
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<listitem><para><emphasis>Using the BitBake that Comes With Your
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Build Checkout:</emphasis>
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A final possibility for getting a copy of BitBake is that it
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already comes with your checkout of a larger Bitbake-based build
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system, such as Poky.
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Rather than manually checking out individual layers and
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gluing them together yourself, you can check
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out an entire build system.
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The checkout will already include a version of BitBake that
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has been thoroughly tested for compatibility with the other
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components.
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For information on how to check out a particular BitBake-based
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build system, consult that build system's supporting documentation.
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</para></listitem>
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</itemizedlist>
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|
</para>
|
|
</section>
|
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|
|
<section id="bitbake-user-manual-command">
|
|
<title>The BitBake Command</title>
|
|
|
|
<para>
|
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The <filename>bitbake</filename> command is the primary interface
|
|
to the BitBake tool.
|
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This section presents the BitBake command syntax and provides
|
|
several execution examples.
|
|
</para>
|
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|
|
<section id='usage-and-syntax'>
|
|
<title>Usage and syntax</title>
|
|
|
|
<para>
|
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Following is the usage and syntax for BitBake:
|
|
<literallayout class='monospaced'>
|
|
$ bitbake -h
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Usage: bitbake [options] [recipename/target recipe:do_task ...]
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|
Executes the specified task (default is 'build') for a given set of target recipes (.bb files).
|
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It is assumed there is a conf/bblayers.conf available in cwd or in BBPATH which
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|
will provide the layer, BBFILES and other configuration information.
|
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|
Options:
|
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--version show program's version number and exit
|
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-h, --help show this help message and exit
|
|
-b BUILDFILE, --buildfile=BUILDFILE
|
|
Execute tasks from a specific .bb recipe directly.
|
|
WARNING: Does not handle any dependencies from other
|
|
recipes.
|
|
-k, --continue Continue as much as possible after an error. While the
|
|
target that failed and anything depending on it cannot
|
|
be built, as much as possible will be built before
|
|
stopping.
|
|
-f, --force Force the specified targets/task to run (invalidating
|
|
any existing stamp file).
|
|
-c CMD, --cmd=CMD Specify the task to execute. The exact options
|
|
available depend on the metadata. Some examples might
|
|
be 'compile' or 'populate_sysroot' or 'listtasks' may
|
|
give a list of the tasks available.
|
|
-C INVALIDATE_STAMP, --clear-stamp=INVALIDATE_STAMP
|
|
Invalidate the stamp for the specified task such as
|
|
'compile' and then run the default task for the
|
|
specified target(s).
|
|
-r PREFILE, --read=PREFILE
|
|
Read the specified file before bitbake.conf.
|
|
-R POSTFILE, --postread=POSTFILE
|
|
Read the specified file after bitbake.conf.
|
|
-v, --verbose Enable tracing of shell tasks (with 'set -x'). Also
|
|
print bb.note(...) messages to stdout (in addition to
|
|
writing them to ${T}/log.do_<task>).
|
|
-D, --debug Increase the debug level. You can specify this more
|
|
than once. -D sets the debug level to 1, where only
|
|
bb.debug(1, ...) messages are printed to stdout; -DD
|
|
sets the debug level to 2, where both bb.debug(1, ...)
|
|
and bb.debug(2, ...) messages are printed; etc.
|
|
Without -D, no debug messages are printed. Note that
|
|
-D only affects output to stdout. All debug messages
|
|
are written to ${T}/log.do_taskname, regardless of the
|
|
debug level.
|
|
-q, --quiet Output less log message data to the terminal. You can
|
|
specify this more than once.
|
|
-n, --dry-run Don't execute, just go through the motions.
|
|
-S SIGNATURE_HANDLER, --dump-signatures=SIGNATURE_HANDLER
|
|
Dump out the signature construction information, with
|
|
no task execution. The SIGNATURE_HANDLER parameter is
|
|
passed to the handler. Two common values are none and
|
|
printdiff but the handler may define more/less. none
|
|
means only dump the signature, printdiff means compare
|
|
the dumped signature with the cached one.
|
|
-p, --parse-only Quit after parsing the BB recipes.
|
|
-s, --show-versions Show current and preferred versions of all recipes.
|
|
-e, --environment Show the global or per-recipe environment complete
|
|
with information about where variables were
|
|
set/changed.
|
|
-g, --graphviz Save dependency tree information for the specified
|
|
targets in the dot syntax.
|
|
-I EXTRA_ASSUME_PROVIDED, --ignore-deps=EXTRA_ASSUME_PROVIDED
|
|
Assume these dependencies don't exist and are already
|
|
provided (equivalent to ASSUME_PROVIDED). Useful to
|
|
make dependency graphs more appealing
|
|
-l DEBUG_DOMAINS, --log-domains=DEBUG_DOMAINS
|
|
Show debug logging for the specified logging domains
|
|
-P, --profile Profile the command and save reports.
|
|
-u UI, --ui=UI The user interface to use (knotty, ncurses or taskexp
|
|
- default knotty).
|
|
--token=XMLRPCTOKEN Specify the connection token to be used when
|
|
connecting to a remote server.
|
|
--revisions-changed Set the exit code depending on whether upstream
|
|
floating revisions have changed or not.
|
|
--server-only Run bitbake without a UI, only starting a server
|
|
(cooker) process.
|
|
-B BIND, --bind=BIND The name/address for the bitbake xmlrpc server to bind
|
|
to.
|
|
-T SERVER_TIMEOUT, --idle-timeout=SERVER_TIMEOUT
|
|
Set timeout to unload bitbake server due to
|
|
inactivity, set to -1 means no unload, default:
|
|
Environment variable BB_SERVER_TIMEOUT.
|
|
--no-setscene Do not run any setscene tasks. sstate will be ignored
|
|
and everything needed, built.
|
|
--setscene-only Only run setscene tasks, don't run any real tasks.
|
|
--remote-server=REMOTE_SERVER
|
|
Connect to the specified server.
|
|
-m, --kill-server Terminate any running bitbake server.
|
|
--observe-only Connect to a server as an observing-only client.
|
|
--status-only Check the status of the remote bitbake server.
|
|
-w WRITEEVENTLOG, --write-log=WRITEEVENTLOG
|
|
Writes the event log of the build to a bitbake event
|
|
json file. Use '' (empty string) to assign the name
|
|
automatically.
|
|
--runall=RUNALL Run the specified task for any recipe in the taskgraph
|
|
of the specified target (even if it wouldn't otherwise
|
|
have run).
|
|
--runonly=RUNONLY Run only the specified task within the taskgraph of
|
|
the specified targets (and any task dependencies those
|
|
tasks may have).
|
|
</literallayout>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='bitbake-examples'>
|
|
<title>Examples</title>
|
|
|
|
<para>
|
|
This section presents some examples showing how to use BitBake.
|
|
</para>
|
|
|
|
<section id='example-executing-a-task-against-a-single-recipe'>
|
|
<title>Executing a Task Against a Single Recipe</title>
|
|
|
|
<para>
|
|
Executing tasks for a single recipe file is relatively simple.
|
|
You specify the file in question, and BitBake parses
|
|
it and executes the specified task.
|
|
If you do not specify a task, BitBake executes the default
|
|
task, which is "build”.
|
|
BitBake obeys inter-task dependencies when doing
|
|
so.
|
|
</para>
|
|
|
|
<para>
|
|
The following command runs the build task, which is
|
|
the default task, on the <filename>foo_1.0.bb</filename>
|
|
recipe file:
|
|
<literallayout class='monospaced'>
|
|
$ bitbake -b foo_1.0.bb
|
|
</literallayout>
|
|
The following command runs the clean task on the
|
|
<filename>foo.bb</filename> recipe file:
|
|
<literallayout class='monospaced'>
|
|
$ bitbake -b foo.bb -c clean
|
|
</literallayout>
|
|
<note>
|
|
The "-b" option explicitly does not handle recipe
|
|
dependencies.
|
|
Other than for debugging purposes, it is instead
|
|
recommended that you use the syntax presented in the
|
|
next section.
|
|
</note>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='executing-tasks-against-a-set-of-recipe-files'>
|
|
<title>Executing Tasks Against a Set of Recipe Files</title>
|
|
|
|
<para>
|
|
There are a number of additional complexities introduced
|
|
when one wants to manage multiple <filename>.bb</filename>
|
|
files.
|
|
Clearly there needs to be a way to tell BitBake what
|
|
files are available and, of those, which you
|
|
want to execute.
|
|
There also needs to be a way for each recipe
|
|
to express its dependencies, both for build-time and
|
|
runtime.
|
|
There must be a way for you to express recipe preferences
|
|
when multiple recipes provide the same functionality, or when
|
|
there are multiple versions of a recipe.
|
|
</para>
|
|
|
|
<para>
|
|
The <filename>bitbake</filename> command, when not using
|
|
"--buildfile" or "-b" only accepts a "PROVIDES".
|
|
You cannot provide anything else.
|
|
By default, a recipe file generally "PROVIDES" its
|
|
"packagename" as shown in the following example:
|
|
<literallayout class='monospaced'>
|
|
$ bitbake foo
|
|
</literallayout>
|
|
This next example "PROVIDES" the package name and also uses
|
|
the "-c" option to tell BitBake to just execute the
|
|
<filename>do_clean</filename> task:
|
|
<literallayout class='monospaced'>
|
|
$ bitbake -c clean foo
|
|
</literallayout>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='executing-a-list-of-task-and-recipe-combinations'>
|
|
<title>Executing a List of Task and Recipe Combinations</title>
|
|
|
|
<para>
|
|
The BitBake command line supports specifying different
|
|
tasks for individual targets when you specify multiple
|
|
targets.
|
|
For example, suppose you had two targets (or recipes)
|
|
<filename>myfirstrecipe</filename> and
|
|
<filename>mysecondrecipe</filename> and you needed
|
|
BitBake to run <filename>taskA</filename> for the first
|
|
recipe and <filename>taskB</filename> for the second
|
|
recipe:
|
|
<literallayout class='monospaced'>
|
|
$ bitbake myfirstrecipe:do_taskA mysecondrecipe:do_taskB
|
|
</literallayout>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='generating-dependency-graphs'>
|
|
<title>Generating Dependency Graphs</title>
|
|
|
|
<para>
|
|
BitBake is able to generate dependency graphs using
|
|
the <filename>dot</filename> syntax.
|
|
You can convert these graphs into images using the
|
|
<filename>dot</filename> tool from
|
|
<ulink url='http://www.graphviz.org'>Graphviz</ulink>.
|
|
</para>
|
|
|
|
<para>
|
|
When you generate a dependency graph, BitBake writes three files
|
|
to the current working directory:
|
|
<itemizedlist>
|
|
<listitem><para>
|
|
<emphasis><filename>recipe-depends.dot</filename>:</emphasis>
|
|
Shows dependencies between recipes (i.e. a collapsed version of
|
|
<filename>task-depends.dot</filename>).
|
|
</para></listitem>
|
|
<listitem><para>
|
|
<emphasis><filename>task-depends.dot</filename>:</emphasis>
|
|
Shows dependencies between tasks.
|
|
These dependencies match BitBake's internal task execution list.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
<emphasis><filename>pn-buildlist</filename>:</emphasis>
|
|
Shows a simple list of targets that are to be built.
|
|
</para></listitem>
|
|
</itemizedlist>
|
|
</para>
|
|
|
|
<para>
|
|
To stop depending on common depends, use the "-I" depend
|
|
option and BitBake omits them from the graph.
|
|
Leaving this information out can produce more readable graphs.
|
|
This way, you can remove from the graph
|
|
<filename>DEPENDS</filename> from inherited classes
|
|
such as <filename>base.bbclass</filename>.
|
|
</para>
|
|
|
|
<para>
|
|
Here are two examples that create dependency graphs.
|
|
The second example omits depends common in OpenEmbedded from
|
|
the graph:
|
|
<literallayout class='monospaced'>
|
|
$ bitbake -g foo
|
|
|
|
$ bitbake -g -I virtual/kernel -I eglibc foo
|
|
</literallayout>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='executing-a-multiple-configuration-build'>
|
|
<title>Executing a Multiple Configuration Build</title>
|
|
|
|
<para>
|
|
BitBake is able to build multiple images or packages
|
|
using a single command where the different targets
|
|
require different configurations (multiple configuration
|
|
builds).
|
|
Each target, in this scenario, is referred to as a
|
|
"multiconfig".
|
|
</para>
|
|
|
|
<para>
|
|
To accomplish a multiple configuration build, you must
|
|
define each target's configuration separately using
|
|
a parallel configuration file in the build directory.
|
|
The location for these multiconfig configuration files
|
|
is specific.
|
|
They must reside in the current build directory in
|
|
a sub-directory of <filename>conf</filename> named
|
|
<filename>multiconfig</filename>.
|
|
Following is an example for two separate targets:
|
|
<imagedata fileref="figures/bb_multiconfig_files.png" align="center" width="4in" depth="3in" />
|
|
</para>
|
|
|
|
<para>
|
|
The reason for this required file hierarchy
|
|
is because the <filename>BBPATH</filename> variable
|
|
is not constructed until the layers are parsed.
|
|
Consequently, using the configuration file as a
|
|
pre-configuration file is not possible unless it is
|
|
located in the current working directory.
|
|
</para>
|
|
|
|
<para>
|
|
Minimally, each configuration file must define the
|
|
machine and the temporary directory BitBake uses
|
|
for the build.
|
|
Suggested practice dictates that you do not
|
|
overlap the temporary directories used during the
|
|
builds.
|
|
</para>
|
|
|
|
<para>
|
|
Aside from separate configuration files for each
|
|
target, you must also enable BitBake to perform multiple
|
|
configuration builds.
|
|
Enabling is accomplished by setting the
|
|
<link linkend='var-bb-BBMULTICONFIG'><filename>BBMULTICONFIG</filename></link>
|
|
variable in the <filename>local.conf</filename>
|
|
configuration file.
|
|
As an example, suppose you had configuration files
|
|
for <filename>target1</filename> and
|
|
<filename>target2</filename> defined in the build
|
|
directory.
|
|
The following statement in the
|
|
<filename>local.conf</filename> file both enables
|
|
BitBake to perform multiple configuration builds and
|
|
specifies the two multiconfigs:
|
|
<literallayout class='monospaced'>
|
|
BBMULTICONFIG = "target1 target2"
|
|
</literallayout>
|
|
</para>
|
|
|
|
<para>
|
|
Once the target configuration files are in place and
|
|
BitBake has been enabled to perform multiple configuration
|
|
builds, use the following command form to start the
|
|
builds:
|
|
<literallayout class='monospaced'>
|
|
$ bitbake [multiconfig:<replaceable>multiconfigname</replaceable>:]<replaceable>target</replaceable> [[[multiconfig:<replaceable>multiconfigname</replaceable>:]<replaceable>target</replaceable>] ... ]
|
|
</literallayout>
|
|
Here is an example for two multiconfigs:
|
|
<filename>target1</filename> and
|
|
<filename>target2</filename>:
|
|
<literallayout class='monospaced'>
|
|
$ bitbake multiconfig:target1:<replaceable>target</replaceable> multiconfig:target2:<replaceable>target</replaceable>
|
|
</literallayout>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='bb-enabling-multiple-configuration-build-dependencies'>
|
|
<title>Enabling Multiple Configuration Build Dependencies</title>
|
|
|
|
<para>
|
|
Sometimes dependencies can exist between targets
|
|
(multiconfigs) in a multiple configuration build.
|
|
For example, suppose that in order to build an image
|
|
for a particular architecture, the root filesystem of
|
|
another build for a different architecture needs to
|
|
exist.
|
|
In other words, the image for the first multiconfig depends
|
|
on the root filesystem of the second multiconfig.
|
|
This dependency is essentially that the task in the recipe
|
|
that builds one multiconfig is dependent on the
|
|
completion of the task in the recipe that builds
|
|
another multiconfig.
|
|
</para>
|
|
|
|
<para>
|
|
To enable dependencies in a multiple configuration
|
|
build, you must declare the dependencies in the recipe
|
|
using the following statement form:
|
|
<literallayout class='monospaced'>
|
|
<replaceable>task_or_package</replaceable>[mcdepends] = "multiconfig:<replaceable>from_multiconfig</replaceable>:<replaceable>to_multiconfig</replaceable>:<replaceable>recipe_name</replaceable>:<replaceable>task_on_which_to_depend</replaceable>"
|
|
</literallayout>
|
|
To better show how to use this statement, consider an
|
|
example with two multiconfigs: <filename>target1</filename>
|
|
and <filename>target2</filename>:
|
|
<literallayout class='monospaced'>
|
|
<replaceable>image_task</replaceable>[mcdepends] = "multiconfig:target1:target2:<replaceable>image2</replaceable>:<replaceable>rootfs_task</replaceable>"
|
|
</literallayout>
|
|
In this example, the
|
|
<replaceable>from_multiconfig</replaceable> is "target1" and
|
|
the <replaceable>to_multiconfig</replaceable> is "target2".
|
|
The task on which the image whose recipe contains
|
|
<replaceable>image_task</replaceable> depends on the
|
|
completion of the <replaceable>rootfs_task</replaceable>
|
|
used to build out <replaceable>image2</replaceable>, which
|
|
is associated with the "target2" multiconfig.
|
|
</para>
|
|
|
|
<para>
|
|
Once you set up this dependency, you can build the
|
|
"target1" multiconfig using a BitBake command as follows:
|
|
<literallayout class='monospaced'>
|
|
$ bitbake multiconfig:target1:<replaceable>image1</replaceable>
|
|
</literallayout>
|
|
This command executes all the tasks needed to create
|
|
<replaceable>image1</replaceable> for the "target1"
|
|
multiconfig.
|
|
Because of the dependency, BitBake also executes through
|
|
the <replaceable>rootfs_task</replaceable> for the "target2"
|
|
multiconfig build.
|
|
</para>
|
|
|
|
<para>
|
|
Having a recipe depend on the root filesystem of another
|
|
build might not seem that useful.
|
|
Consider this change to the statement in the
|
|
<replaceable>image1</replaceable> recipe:
|
|
<literallayout class='monospaced'>
|
|
<replaceable>image_task</replaceable>[mcdepends] = "multiconfig:target1:target2:<replaceable>image2</replaceable>:<replaceable>image_task</replaceable>"
|
|
</literallayout>
|
|
In this case, BitBake must create
|
|
<replaceable>image2</replaceable> for the "target2"
|
|
build since the "target1" build depends on it.
|
|
</para>
|
|
|
|
<para>
|
|
Because "target1" and "target2" are enabled for multiple
|
|
configuration builds and have separate configuration
|
|
files, BitBake places the artifacts for each build in the
|
|
respective temporary build directories.
|
|
</para>
|
|
</section>
|
|
</section>
|
|
</section>
|
|
</chapter>
|