https://github.com/Kitware/CMake
Tip revision: 6c71fa6d56d3e2de30de3e0eb1d72375530598c4 authored by Brad King on 14 March 2023, 14:04:14 UTC
CMake 3.26.0
CMake 3.26.0
Tip revision: 6c71fa6
external.rst
CPack External Generator
------------------------
.. versionadded:: 3.13
CPack provides many generators to create packages for a variety of platforms
and packaging systems. The intention is for CMake/CPack to be a complete
end-to-end solution for building and packaging a software project. However, it
may not always be possible to use CPack for the entire packaging process, due
to either technical limitations or policies that require the use of certain
tools. For this reason, CPack provides the "External" generator, which allows
external packaging software to take advantage of some of the functionality
provided by CPack, such as component installation and the dependency graph.
Integration with External Packaging Tools
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The CPack External generator generates a ``.json`` file containing the
CPack internal metadata, which gives external software information
on how to package the software. External packaging software may itself
invoke CPack, consume the generated metadata,
install and package files as required.
Alternatively CPack can invoke an external packaging software
through an optional custom CMake script in
:variable:`CPACK_EXTERNAL_PACKAGE_SCRIPT` instead.
Staging of installation files may also optionally be
taken care of by the generator when enabled through the
:variable:`CPACK_EXTERNAL_ENABLE_STAGING` variable.
JSON Format
^^^^^^^^^^^
The JSON metadata file contains a list of CPack components and component groups,
the various options passed to :command:`cpack_add_component` and
:command:`cpack_add_component_group`, the dependencies between the components
and component groups, and various other options passed to CPack.
The JSON's root object will always provide two fields:
``formatVersionMajor`` and ``formatVersionMinor``, which are always integers
that describe the output format of the generator. Backwards-compatible changes
to the output format (for example, adding a new field that didn't exist before)
cause the minor version to be incremented, and backwards-incompatible changes
(for example, deleting a field or changing its meaning) cause the major version
to be incremented and the minor version reset to 0. The format version is
always of the format ``major.minor``. In other words, it always has exactly two
parts, separated by a period.
You can request one or more specific versions of the output format as described
below with :variable:`CPACK_EXTERNAL_REQUESTED_VERSIONS`. The output format will
have a major version that exactly matches the requested major version, and a
minor version that is greater than or equal to the requested minor version. If
no version is requested with :variable:`CPACK_EXTERNAL_REQUESTED_VERSIONS`, the
latest known major version is used by default. Currently, the only supported
format is 1.0, which is described below.
Version 1.0
***********
In addition to the standard format fields, format version 1.0 provides the
following fields in the root:
``components``
The ``components`` field is an object with component names as the keys and
objects describing the components as the values. The component objects have
the following fields:
``name``
The name of the component. This is always the same as the key in the
``components`` object.
``displayName``
The value of the ``DISPLAY_NAME`` field passed to
:command:`cpack_add_component`.
``description``
The value of the ``DESCRIPTION`` field passed to
:command:`cpack_add_component`.
``isHidden``
True if ``HIDDEN`` was passed to :command:`cpack_add_component`, false if
it was not.
``isRequired``
True if ``REQUIRED`` was passed to :command:`cpack_add_component`, false if
it was not.
``isDisabledByDefault``
True if ``DISABLED`` was passed to :command:`cpack_add_component`, false if
it was not.
``group``
Only present if ``GROUP`` was passed to :command:`cpack_add_component`. If
so, this field is a string value containing the component's group.
``dependencies``
An array of components the component depends on. This contains the values
in the ``DEPENDS`` argument passed to :command:`cpack_add_component`. If no
``DEPENDS`` argument was passed, this is an empty list.
``installationTypes``
An array of installation types the component is part of. This contains the
values in the ``INSTALL_TYPES`` argument passed to
:command:`cpack_add_component`. If no ``INSTALL_TYPES`` argument was
passed, this is an empty list.
``isDownloaded``
True if ``DOWNLOADED`` was passed to :command:`cpack_add_component`, false
if it was not.
``archiveFile``
The name of the archive file passed with the ``ARCHIVE_FILE`` argument to
:command:`cpack_add_component`. If no ``ARCHIVE_FILE`` argument was passed,
this is an empty string.
``componentGroups``
The ``componentGroups`` field is an object with component group names as the
keys and objects describing the component groups as the values. The component
group objects have the following fields:
``name``
The name of the component group. This is always the same as the key in the
``componentGroups`` object.
``displayName``
The value of the ``DISPLAY_NAME`` field passed to
:command:`cpack_add_component_group`.
``description``
The value of the ``DESCRIPTION`` field passed to
:command:`cpack_add_component_group`.
``parentGroup``
Only present if ``PARENT_GROUP`` was passed to
:command:`cpack_add_component_group`. If so, this field is a string value
containing the component group's parent group.
``isExpandedByDefault``
True if ``EXPANDED`` was passed to :command:`cpack_add_component_group`,
false if it was not.
``isBold``
True if ``BOLD_TITLE`` was passed to :command:`cpack_add_component_group`,
false if it was not.
``components``
An array of names of components that are direct members of the group
(components that have this group as their ``GROUP``). Components of
subgroups are not included.
``subgroups``
An array of names of component groups that are subgroups of the group
(groups that have this group as their ``PARENT_GROUP``).
``installationTypes``
The ``installationTypes`` field is an object with installation type names as
the keys and objects describing the installation types as the values. The
installation type objects have the following fields:
``name``
The name of the installation type. This is always the same as the key in
the ``installationTypes`` object.
``displayName``
The value of the ``DISPLAY_NAME`` field passed to
:command:`cpack_add_install_type`.
``index``
The integer index of the installation type in the list.
``projects``
The ``projects`` field is an array of objects describing CMake projects which
comprise the CPack project. The values in this field are derived from
:variable:`CPACK_INSTALL_CMAKE_PROJECTS`. In most cases, this will be only a
single project. The project objects have the following fields:
``projectName``
The project name passed to :variable:`CPACK_INSTALL_CMAKE_PROJECTS`.
``component``
The name of the component or component set which comprises the project.
``directory``
The build directory of the CMake project. This is the directory which
contains the ``cmake_install.cmake`` script.
``subDirectory``
The subdirectory to install the project into inside the CPack package.
``packageName``
The package name given in :variable:`CPACK_PACKAGE_NAME`. Only present if
this option is set.
``packageVersion``
The package version given in :variable:`CPACK_PACKAGE_VERSION`. Only present
if this option is set.
``packageDescriptionFile``
The package description file given in
:variable:`CPACK_PACKAGE_DESCRIPTION_FILE`. Only present if this option is
set.
``packageDescriptionSummary``
The package description summary given in
:variable:`CPACK_PACKAGE_DESCRIPTION_SUMMARY`. Only present if this option is
set.
``buildConfig``
The build configuration given to CPack with the :option:`cpack -C` option.
Only present if this option is set.
``defaultDirectoryPermissions``
The default directory permissions given in
:variable:`CPACK_INSTALL_DEFAULT_DIRECTORY_PERMISSIONS`. Only present if this
option is set.
``setDestdir``
True if :variable:`CPACK_SET_DESTDIR` is true, false if it is not.
``packagingInstallPrefix``
The install prefix given in :variable:`CPACK_PACKAGING_INSTALL_PREFIX`. Only
present if :variable:`CPACK_SET_DESTDIR` is true.
``stripFiles``
True if :variable:`CPACK_STRIP_FILES` is true, false if it is not.
``warnOnAbsoluteInstallDestination``
True if :variable:`CPACK_WARN_ON_ABSOLUTE_INSTALL_DESTINATION` is true, false
if it is not.
``errorOnAbsoluteInstallDestination``
True if :variable:`CPACK_ERROR_ON_ABSOLUTE_INSTALL_DESTINATION` is true,
false if it is not.
Variables specific to CPack External generator
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. variable:: CPACK_EXTERNAL_REQUESTED_VERSIONS
This variable is used to request a specific version of the CPack External
generator. It is a list of ``major.minor`` values, separated by semicolons.
If this variable is set to a non-empty value, the CPack External generator
will iterate through each item in the list to search for a version that it
knows how to generate. Requested versions should be listed in order of
descending preference by the client software, as the first matching version
in the list will be generated.
The generator knows how to generate the version if it has a versioned
generator whose major version exactly matches the requested major version,
and whose minor version is greater than or equal to the requested minor
version. For example, if ``CPACK_EXTERNAL_REQUESTED_VERSIONS`` contains 1.0, and
the CPack External generator knows how to generate 1.1, it will generate 1.1.
If the generator doesn't know how to generate a version in the list, it skips
the version and looks at the next one. If it doesn't know how to generate any
of the requested versions, an error is thrown.
If this variable is not set, or is empty, the CPack External generator will
generate the highest major and minor version that it knows how to generate.
If an invalid version is encountered in ``CPACK_EXTERNAL_REQUESTED_VERSIONS`` (one
that doesn't match ``major.minor``, where ``major`` and ``minor`` are
integers), it is ignored.
.. variable:: CPACK_EXTERNAL_ENABLE_STAGING
This variable can be set to true to enable optional installation
into a temporary staging area which can then be picked up
and packaged by an external packaging tool.
The top level directory used by CPack for the current packaging
task is contained in ``CPACK_TOPLEVEL_DIRECTORY``.
It is automatically cleaned up on each run before packaging is initiated
and can be used for custom temporary files required by
the external packaging tool.
It also contains the staging area ``CPACK_TEMPORARY_DIRECTORY``
into which CPack performs the installation when staging is enabled.
.. variable:: CPACK_EXTERNAL_PACKAGE_SCRIPT
This variable can optionally specify the full path to
a CMake script file to be run as part of the CPack invocation.
It is invoked after (optional) staging took place and may
run an external packaging tool. The script has access to
the variables defined by the CPack config file.
.. variable:: CPACK_EXTERNAL_BUILT_PACKAGES
.. versionadded:: 3.19
The ``CPACK_EXTERNAL_PACKAGE_SCRIPT`` script may set this list variable to the
full paths of generated package files. CPack will copy these files from the
staging directory back to the top build directory and possibly produce
checksum files if the :variable:`CPACK_PACKAGE_CHECKSUM` is set.