Tutorial de Empaquetamiento: GNU Hello
Este tutorial demuestra el empaquetamiento RPM empaquetando el programa GNU Hello. Si bien el programa es sencillo, viene con la mayoría de los componentes periféricos de un proyecto FOSS: entorno de configuración/compilación/instalación, documentación, internacionalización, etc. Sin embargo, no incluye información de empaquetamiento RPM, por lo tanto es un vehículo razonable para practicar la construcción de RPMs.
Para una información completa sobre como crear archivos RPM, vea el Manual de Referencia RPM. Si planea crear un paquete RPM para el repositorio Fedora, siga el proceso para Unirse a los Mantenedores de Paquetes, incluyendo seguir las diversas pautas de Fedora.
Este tutorial está diseñado para ejecutarse en un sistema 38. Debería, sin embargo, trabajar también para otras versiones de Fedora. Solo reemplace las cadenas f38
con su número de versión. Es poco probable que funcione en los software downstream de Fedora como CentOS Stream o Red Hat Enterprise Linux, puesto que este tutorial usa herramientas y funciones específicas y muy recientes de Fedora. En concreto, rpmautospec es poco probable que esté disponible.
El tutorial sigue una forma de paso a paso, con la mayoría de los pasos editando el archivo de especificaciones del paquete. El archivo de especificaciones resultante se lista al final, de modo que, en caso de que no quede claro cómo se debe aplicar un cambio en particular, puede echar un vistazo.
Crear el directorio del paquete
En Fedora, las instrucciones de compilación del paquete están organizadas en los llamados repositorios dist-git. Hay un repositorio separado para cada paquete. Imitamos este sistema creando un nuevo directorio para este tutorial. En dist-git, el nombre del repositorio coincide con el nombre del paquete. Las reglas de Fedora para la denominación de los paquetes están escritas en Directrices de Denominación. Para GNU Hello, el paquete puede llamarse simplemente hello
. Este es también el nombre oficial del paquete GNU Hello de Fedora.
$ mkdir hello && cd hello
Dentro de un Archivo de Especificaciones
Los paquetes RPM están configurados por archivos .spec
. Herramientas como rpmdev-newspec
se pueden usar para generar archivos de especificaciones vacíos para diferentes propósitos. Para este tutorial, solo cree un archivo llamado hello.spec
y pegue el siguiente archivo de especificaciones mínimo. No funciona todavía, pero intentaremos construirlo y corregir los errores según los vayamos encontrando.
Name: hello
Version: 2.10
Release: %autorelease
Summary: Produces a familiar, friendly greeting
License: GPL-3.0-or-later
URL: https://www.gnu.org/software/hello/
Source: http://ftp.gnu.org/gnu/hello/hello-%{version}.tar.gz
%description
The GNU Hello program produces a familiar, friendly greeting. Yes, this is
another implementation of the classic program that prints "Hello, world!" when
you run it.
%prep
%autosetup
%build
%configure
%make_build
%install
%make_install
%files
%changelog
%autochangelog
El archivo de especificaciones comienza con un conjunto de etiquetas, como Name:
y Version:
, seguido de secciones como %description
y %prep
. Cada etiqueta se ajusta a un única línea, mientras que cada sección continúa hasta que comienza la siguiente.
Tenga en cuenta que, de manera confusa, además de marcar los nombres de sección el signo porcentaje %
marca también las macros RPM. Así, por ejemplo %autosetup
, %configure
y %make_build
no son secciones.
Etiquetas
Version
contiene el número de versión del software empaquetado.
Release
numera las actualizaciones del fichero de especificaciones, las reconstrucciones del paquete y otro trabajo dentro de Fedora. El valor usado aquí, %autorelease
, es parte de rpmautospec, que es el recomendado para los paquetes de Fedora. Se vincula Release
al histórico Git del paquete. Como no tenemos un repositorio Git, %autorelease
se evaluará al valor predeterminado de 1.
Con frecuencia, Summary
puede ser copiado del README de arriba. La primera letra debe ir en mayúscula para evitar quejas sobre rpmlint
.
License
describe la licencia del paquete binario resultante usando un identificador de licencia SPDX. Debe seguir las directrices de licenciamiento de Fedora. En la práctica, determinar el valor correcto significa, con frecuencia, inspeccionar las notificaciones de licencias en los archivos fuente individuales. También se puede necesitar preguntar a los desarrolladores upstream para lograr clarificaciones o correcciones. En este tutorial, simplemente tomamos la palabra de la fuente de que la licencia es la GNU Public License, versión 3 o posterior.
URL
apunta al sitio web de desarrollo del proyecto.
Source
define las fuentes de desarrollo usadas cuando se construye el paquete. Usualmente, como en este caso, es una url apuntando a un tarball lanzado por el desarrollador, pero también puede ser un archivo local. Puede haber múltiples etiquetas Source
si es necesario.
Sections
%description
can often be copied from upstream README.
%prep
contains a shell script for preparing the sources for building. It is often just the single macro %autosetup
, which, in this case, simply extracts the source.
%build
contains a shell script for the required build steps, such as compiling sources to binaries. GNU Hello uses Autotools as its buildsystem, so building involves running configure
and make
. Macros %configure
and %make_build
invoke these commands using Fedora’s compilation flags and other configuration.
%install
contains a shell script to copy the results from %build
into an initially empty build root directory. As GNU Hello is using Autotools, macro %make_install
is used.
%files
lists the content of the resulting package. Mostly, the files come from the build root created in the %install
, but documentation and license files can also be added directly from the sources. This section is left empty for now, to be filled later.
The %changelog
documents the changes in each new package version and release. Changelog data can be displayed by rpm --query --changelog PACKAGE_NAME
, which can be useful, for instance, to find out if specific bug and security patches are included. Its value,%autochangelog
, also comes from rpmautospec
. It populates the changelog from Git commit messages. As we do not have a Git repository, the changelog will be empty.
Lines which are not needed can be commented out with the hash #
.
You can find more information in the RPM Reference Manual’s section Spec file format.
Downloading source
We need the source code defined by the Source
tag, often referred to as the upstream source. This is most easily achieved by using the spectool
command:
$ spectool -g hello.spec
You should now have the file listed in Source
in your working directory:
$ ls *.tar.gz hello-2.10.tar.gz
Building the Package
We are ready for the first run to build source, binary and debugging packages. This, and many other tasks, are done with the fedpkg
tool. The production builds for Fedora are built in the Koji build system, which in turn uses Mock to manage isolated build environments. To get as close to a production build as is locally possible, we use the fedpkg mockbuild
command which also invokes Mock:
$ fedpkg --release f38 mockbuild
The build environment created by Mock is very basic. It does not include a C compiler by default, so the build will fail. The reason is explained in the output:
checking whether the C compiler works... no configure: error: in `/builddir/build/BUILD/hello-2.10': configure: error: C compiler cannot create executables See `config.log' for more details error: Bad exit status from /var/tmp/rpm-tmp.D2nN0w (%build) Bad exit status from /var/tmp/rpm-tmp.D2nN0w (%build)
Additional build tools are defined by adding BuildRequires:
rows to the specfile. In Fedora, GCC is the standard compiler, so we need to add a row for gcc
. GNU Hello also uses make
, so a row should be added for it, too. Add these lines after Source
:
BuildRequires: gcc
BuildRequires: make
For reasons that are too complex to explain in a tutorial, in some situations texinfo
package is also needed. To avoid a possible error, add one more row:
BuildRequires: texinfo
Run a mockbuild again. The earlier error should be gone.
Installing files
The next thing rpm will complain about are unpackaged files, i.e. the files that would be installed in the system, but were not declared as belonging to the package. We need to declare them in the %files
section. Fixing these errors is an iterative process. After declaring a missing file in the .spec
file, run fedpkg
again, then declare the next missing file and so on.
We will go through the file list one by one.
Executable
Installed (but unpackaged) file(s) found: /usr/bin/hello
This is the executable binary program. /usr/bin
, like many other system directories, have a default rpm macro defined. The macros should always be used when available, so the executable is listed in %files
as follows:
%files
%{_bindir}/hello
Man pages
Installed (but unpackaged) file(s) found: /usr/share/man/man1/hello.1.gz
The Packaging Guidelines have a dedicated section for Manpages. Following its instructions, manpages are list as follows:
%{_mandir}/man1/hello.1.*
Texinfo pages
Installed (but unpackaged) file(s) found: /usr/share/info/dir /usr/share/info/hello.info.gz
Texinfo pages are handled much in the same way as man pages. The directory is defined by the default macro {_infodir}
, so the Texinfo manual can be added as follows:
%{_infodir}/hello.info.*
The dir
file generated by GNU Hello build script indexes all texinfo pages in your system. Because the installed pages differ among systems, the file cannot be prebuilt and packaged. Instead it needs to be created and updated when the package is installed. The update is automatically performed by rpm triggers in info
binary package of texinfo source package.
To prevent from installing the dir
file, remove it from the buildroot at the end of the %install
section with rm
command.
However, GNU Hello build script only generates the dir
file if info
package is installed during the build. Blindly removing the file would raise an error if the hello
package were built on a system without info
package. To deal with both cases, delete the file if it exists:
%install
%make_install
test -f %{buildroot}/%{_infodir}/dir && rm %{buildroot}/%{_infodir}/dir
Translations
Installed (but unpackaged) file(s) found: /usr/share/locale/bg/LC_MESSAGES/hello.mo /usr/share/locale/ca/LC_MESSAGES/hello.mo /usr/share/locale/da/LC_MESSAGES/hello.mo ...
Since our program uses translations and internationalization, we are seeing a lot of undeclared i18n files. The recommended method to declare them is:
-
Add the required build dependency with
BuildRequires: gettext
. -
Find the filenames in the
%install
step with%find_lang %{name}
. -
Install the files with
%files -f %{name}.lang
.
License file
Every package must install its license, tagged with %license
directive. In GNU Hello’s case, as well as for many other projects, the license file is located at the source tarball’s top level, and perhaps not copied to the buildroot during installation at all. Regardless, it can be installed to the standard license directory by using a relative path:
%license COPYING
Additional documentation
Often, package sources contain documentation that could be useful for the end users as well. These can be installed and marked as documentation with the %doc
directive. Similarly to %license
, relative paths can be used to include files directly from the source tarball rather than from the buildroot:
%doc AUTHORS ChangeLog NEWS README THANKS TODO
Running tests
GNU Hello, like many other projects, includes an automated test suite in the sources. If at all possible, the test suite should be run during the rpm build. This helps ensuring that a working build was produced. This is done by adding the test suite invocation to specfile %check%
section, which comes after %install
in order. In GNU Hello’s case:
%check
make check
Run a mockbuild again and check the output to ensure that the tests were actually run. Something like this should be somewhere in the output:
============================================================================ Testsuite summary for GNU Hello 2.10 ============================================================================ # TOTAL: 5 # PASS: 4 # SKIP: 1 # XFAIL: 0 # FAIL: 0 # XPASS: 0 # ERROR: 0 ============================================================================
Fixing automagic
Now the package succefully builds. But that does not mean that the .spec
file is correct.
Listing all build-time dependencies
If you carefully read a build output, you can discover lines which mention sed
command:
+ /usr/bin/make -O -j4 V=1 VERBOSE=1 rm -f lib/arg-nonnull.h-t lib/arg-nonnull.h && \ sed -n -e '/GL_ARG_NONNULL/,$p' \
Therefore you need to add this line close to other BuildRequires lines:
BuildRequires: sed
Smilarly, studying configure
script in the unpackaged sources, which is executed by %configure
macro, reveals it’s a /bin/sh
script:
$ head configure #! /bin/sh # Guess values for system-dependent variables and create Makefiles. # Generated by GNU Autoconf 2.69 for GNU Hello 2.10.
Thus you also should record this dependency on bash
:
BuildRequires: bash
Why on bash
? Because /bin/sh
program is provided by bash
package:
rpm --qf '%{name}\n' -qf /bin/sh bash
Specifying all used dependencies helps to make the .spec
file resilient against changes in the build environment. If e.g. sed
package were removed from the environment, this GNU Hello package would fail to build.
Listing all build options
The GNU Hello build script, configure
has many build options which enables or disables optional features. Their nondefault forms can be listed with --help
option:
$ ./configure --help `configure' configures GNU Hello 2.10 to adapt to many kinds of systems. Usage: ./configure [OPTION]... [VAR=VALUE]... ⋮ Optional Features: --disable-option-checking ignore unrecognized --enable/--with options --disable-FEATURE do not include FEATURE (same as --enable-FEATURE=no) --enable-FEATURE[=ARG] include FEATURE [ARG=yes] --enable-silent-rules less verbose build output (undo: "make V=1") --disable-silent-rules verbose build output (undo: "make V=0") --enable-dependency-tracking do not reject slow dependency extractors --disable-dependency-tracking speeds up one-time build --disable-nls do not use Native Language Support --disable-rpath do not hardcode runtime library paths
Some of them are already specified within %configure
and %make_build
macros. The rest of the options, if they are important for the built package, should be explicitly written in the .spec
file to prevent from their sudden and unnoticed changes. Either because a new Hello version changes the default, or because a package which they depend on appears of disappears from the build environment.
Therefore modify %configure
invocation in %build
section like this:
%configure \
--enable-nls \
--disable-rpath
Checking the result with rpmlint
Next you should check them for conformance with RPM design rules, by running rpmlint
on specfile, source rpm and binary rpm. Command fedpkg lint
does this:
$ fedpkg --release f38 lint
If all is good, there should be no warnings or errors. In the GNU Hello case, one warning can be expected:
hello.x86_64: W: file-not-utf8 /usr/share/doc/hello/THANKS
Descriptions of various error codes can be queried with rpmlint -e <error_code>
. In this case, in order to ensure a pure utf-8 installation, the file needs to be converted in %prep
. This can be done with the iconv
utility which is provided by glibc-common
package, and mv
tool from coreutils
:
BuildRequires: coreutils BuildRequires: glibc-common ⋮ mv THANKS THANKS.old iconv --from-code=ISO-8859-1 --to-code=UTF-8 --output=THANKS THANKS.old
Run fedpkg lint
again and observe that the warning is fixed.
A Complete hello.spec File
Here is the final version of hello.spec
:
Name: hello
Version: 2.10
Release: %autorelease
Summary: Produces a familiar, friendly greeting
License: GPL-3.0-or-later
URL: http://ftp.gnu.org/gnu/%{name}
Source: http://ftp.gnu.org/gnu/%{name}/%{name}-%{version}.tar.gz
BuildRequires: bash
BuildRequires: coreutils
BuildRequires: gcc
BuildRequires: gettext
BuildRequires: glibc-common
BuildRequires: make
BuildRequires: sed
BuildRequires: texinfo
%description
The GNU Hello program produces a familiar, friendly greeting. Yes, this is
another implementation of the classic program that prints "Hello, world!" when
you run it.
%prep
%autosetup
mv THANKS THANKS.old
iconv --from-code=ISO-8859-1 --to-code=UTF-8 --output=THANKS THANKS.old
%build
%configure \
--enable-nls \
--disable-rpath
%make_build
%install
%make_install
test -f %{buildroot}/%{_infodir}/dir && rm %{buildroot}/%{_infodir}/dir
%find_lang %{name}
%check
make check
%files -f %{name}.lang
%{_mandir}/man1/hello.1.*
%{_infodir}/hello.info.*
%{_bindir}/hello
%doc AUTHORS ChangeLog NEWS README THANKS TODO
%license COPYING
%changelog
%autochangelog
With this .spec
file, you should be able to successfully complete the build process, and create the source and binary RPM packages.
Checking the result
Having a working specfile and rpms built from it, the result can be checked. Before checking the result by installing the package, let us do some simple checks. The RPM Package Manager rpm
can be used for this.
Files
List the files contained in the package:
$ rpm --query --package --list results_hello/2.10/1.fc38/hello-2.10-1.fc38.x86_64.rpm /usr/bin/hello /usr/lib/.build-id /usr/lib/.build-id/39 /usr/lib/.build-id/39/c97ecb15c6292ce23e8b00e15e6e72a61e5072 /usr/share/doc/hello /usr/share/doc/hello/AUTHORS /usr/share/doc/hello/ChangeLog /usr/share/doc/hello/NEWS /usr/share/doc/hello/README /usr/share/doc/hello/THANKS /usr/share/doc/hello/TODO /usr/share/info/hello.info.gz /usr/share/licenses/hello /usr/share/licenses/hello/COPYING /usr/share/locale/bg/LC_MESSAGES/hello.mo ... /usr/share/locale/zh_TW/LC_MESSAGES/hello.mo /usr/share/man/man1/hello.1.gz
You can see that all the files listed in the specfile %files
section are included, including the automatically processed locale files. Also, under /usr/lib/.build-id
, there is an automatically generated file. It is actually a symlink, mapping a build id to the hello
binary for debugging purposes.
Requires
List the package’s runtime dependencies with the following command:
$ rpm --query --package --requires results_hello/2.10/1.fc38/hello-2.10-1.fc38.x86_64.rpm libc.so.6()(64bit) libc.so.6(GLIBC_2.14)(64bit) libc.so.6(GLIBC_2.2.5)(64bit) libc.so.6(GLIBC_2.3)(64bit) libc.so.6(GLIBC_2.3.4)(64bit) libc.so.6(GLIBC_2.34)(64bit) libc.so.6(GLIBC_2.4)(64bit) libc.so.6(GLIBC_2.7)(64bit) rpmlib(CompressedFileNames) <= 3.0.4-1 rpmlib(FileDigests) <= 4.6.0-1 rpmlib(PayloadFilesHavePrefix) <= 4.0-1 rpmlib(PayloadIsZstd) <= 5.4.18-1 rtld(GNU_HASH)
To check which packages in Fedora repositories provide these dependencies, you can use dnf repoquery
:
$ dnf -C repoquery --whatprovides 'libc.so.6()(64bit)' glibc-0:2.34-11.fc38.x86_64 glibc-0:2.34-7.fc38.x86_64
You will see that the only dependency of GNU Hello is glibc
, which provides symbols in libc.so.6
as well as rtld(GNU_HASH)
.
The rpmlib
requires are special. These specify various rpm features used in the rpm package itself, constraining the version of rpm
that can be used to install the package.
Provides
Conversely, to check what capabilities the package provides, you can do:
$ rpm --query --package --provides results_hello/2.10/1.fc38/hello-2.10-1.fc38.x86_64.rpm hello = 2.10-1.fc38 hello(x86-64) = 2.10-1.fc38
The provides of this package are very simple. It simply provides its own name, in plain and architecture specific forms.
Building in Fedora infrastructure
Even though the package is not part of Fedora distribution yet, a scratch build can be performed to ensure that the package builds successfully in Fedora’s Koji build system, and that it builds successfully for all architectures supported by Fedora. Such build is started by passing a source rpm package to fedpkg scratch-build
.
Note that Koji uses Kerberos for authentication. See Acquiring Kerberos Ticket for details.
$ fedpkg --release f38 scratch-build --srpm results_hello/2.10/1.fc38/hello-2.10-1.fc38.src.rpm Building hello-2.10-1.fc38.src.rpm for f38-candidate Created task: 92465688 Task info: https://koji.fedoraproject.org/koji/taskinfo?taskID=92465688 Watching tasks (this may be safely interrupted)...
You can open the task info link in a browser to view build progress, logs and results. The command line program also reports on progress as it happens. Successful execution looks something like this:
92465688 build (f38-candidate, hello-2.10-1.fc38.src.rpm): free 92465688 build (f38-candidate, hello-2.10-1.fc38.src.rpm): free -> open (buildvm-ppc64le-25.iad2.fedoraproject.org) 92465698 rebuildSRPM (noarch): open (buildvm-s390x-24.s390.fedoraproject.org) 92465745 buildArch (hello-2.10-1.fc38.src.rpm, x86_64): free 92465748 buildArch (hello-2.10-1.fc38.src.rpm, s390x): open (buildvm-s390x-19.s390.fedoraproject.org) 92465746 buildArch (hello-2.10-1.fc38.src.rpm, aarch64): open (buildvm-a64-26.iad2.fedoraproject.org) 92465747 buildArch (hello-2.10-1.fc38.src.rpm, ppc64le): open (buildvm-ppc64le-11.iad2.fedoraproject.org) 92465744 buildArch (hello-2.10-1.fc38.src.rpm, i686): open (buildhw-x86-12.iad2.fedoraproject.org) 92465698 rebuildSRPM (noarch): open (buildvm-s390x-24.s390.fedoraproject.org) -> closed 1 free 5 open 1 done 0 failed 92465745 buildArch (hello-2.10-1.fc38.src.rpm, x86_64): free -> open (buildhw-x86-06.iad2.fedoraproject.org) 92465745 buildArch (hello-2.10-1.fc38.src.rpm, x86_64): open (buildhw-x86-06.iad2.fedoraproject.org) -> closed 0 free 5 open 2 done 0 failed 92465748 buildArch (hello-2.10-1.fc38.src.rpm, s390x): open (buildvm-s390x-19.s390.fedoraproject.org) -> closed 0 free 4 open 3 done 0 failed 92465746 buildArch (hello-2.10-1.fc38.src.rpm, aarch64): open (buildvm-a64-26.iad2.fedoraproject.org) -> closed 0 free 3 open 4 done 0 failed 92465744 buildArch (hello-2.10-1.fc38.src.rpm, i686): open (buildhw-x86-12.iad2.fedoraproject.org) -> closed 0 free 2 open 5 done 0 failed 92465688 build (f38-candidate, hello-2.10-1.fc38.src.rpm): open (buildvm-ppc64le-25.iad2.fedoraproject.org) -> closed 0 free 1 open 6 done 0 failed 92465747 buildArch (hello-2.10-1.fc38.src.rpm, ppc64le): open (buildvm-ppc64le-11.iad2.fedoraproject.org) -> closed 0 free 0 open 7 done 0 failed 92465688 build (f38-candidate, hello-2.10-1.fc38.src.rpm) completed successfully
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