Building RPMs
Basics of Building RPMs
As a rule of thumb do all of the following as a non-root user!
Create the directory tree like the following:
# Create a working dir
mkdir rpmbuild
cd rpmbuild
# Mandatory directories to build the RPM
mkdir -p {BUILD,SPECS,SOURCES,RPMS,SRPMS}
Specify the build area:
# Add the following line to ~/.rpmmacros (create it
# if it doesn't exist)
%_topdir (echo $HOME)/rpmbuild
Macros
The ~/.rpmmacros file contains global macros defined as %{macroname}. Notice the global macro birthmark of preceding the name. These global variables are accessible to all .spec files.
Local macros defined in the .spec file take the form of %{macroname}
Usually in the preamble section of a spec file you will see something like this:
Name: test
Version: 1.0
Release: 0
...
The above fields can then later be referenced as:
# Source0: test-1.0.zip
Source0: %{name}-%{version}.zip
Examples of built-in macros
%_prefix /usr
%_sysconfdir /etc
%_localstatedir /var
%_infodir /usr/share/info
%_mandir /usr/share/man
%_initrddir %{_sysconfdir}/rc.d/init.d
%_defaultdocdir %{_usr}/share/doc
How to define custom macros?
In addition to the built-in macros, you can define your own to make it easier to manage your packages.
#%define macro_name value
%define major 2
# Accessing macro
%{major}
How to pass custom macros as arguments?
When you run rpmbuild you can provide it with arguments which can then be used within your .spec file:
# command
rpmbuild -ba --define "package_version 1.2" myrpm-rpmbuild/SPEC/myrpm.spec
As highlighted in the previous section 'package_version' can be used as %{package_version} in the myrpm.spec file as shown below:
Name: myrpm
Version: %{package_version}
Deep Dive
Lets jump into building a RPM with a real example. We will be packaging a php application.
Before we start I'm going to show you what the final spec file will look like and then I'll go on to explaining each part.
Name: silex-app
Version: 1.0
Release: 1
Group: Development/Libraries
Summary: PHP Silex App
License: MIT
Source0: %{name}-%{version}.zip
BuildRoot: %{_tmppath}/%{name}-%{version}-buildroot
%description
This is an example of a PHP Silex app packaged as a RPM
%prep
# Unzip source file to BUILD dir
unzip %{SOURCE0}
%build
# The build section includes instructions, which are used to build and prepare the package for installation.
%install
# You must create these directories within the BuildRoot so you don't mess with the system directory
# Create the directories as it should look like in your system directory
# Normally in the make install process you set DESTDIR=${RPM_BUILD_ROOT} to achieve this
mkdir %{buildroot}
mkdir -p -m0755 %{buildroot}/var/
cp -r %{_builddir}/%{name}-%{version}/www %{buildroot}/var/
cp -r %{_builddir}/%{name}-%{version}/src %{buildroot}/var/
cp -r %{_builddir}/%{name}-%{version}/tests %{buildroot}/var/
cp -r %{_builddir}/%{name}-%{version}/composer.* %{buildroot}/var/
%clean
rm -rf %{buildroot}
# Removed the unzipped file from the BUILD dir
rm -rf %{_builddir}/%{name}*
# Remove source file
rm %{SOURCE0}
%files
# Set the permissions to the files/directories created
%defattr(-,apache,apache,-)
# Speicfy file/dir created
# Note that exact files must be specified so that when you remove the rpm those files/dirs are also removed
/var/www
/var/src
/var/tests
/var/composer.*
%changelog
* Sun Jul 13 2008 <[email protected]>
- Initial Build.
Taking the .spec File Apart
Preamble
Name: silex-app
Version: 1.4.5
Release: 1
Group: Development/Libraries
Summary: PHP Silex App
License: Telstra Application Technologies
Source0: %{name}-%{version}.zip
BuildRoot: %{_tmppath}/%{name}-%{version}-buildroot
What is the Name field? Name of the source file.
What is the Group field? If you're publishing your RPM for public consumption then you should use existing Groups. If its only internal to your Organization you're free to call it whatever you want.
# Find out what groups you have
less /usr/share/doc/rpm-*/GROUPS
What is the Source0 field? As we've already covered your source file should be placed in the SOURCES dir and Source0 should be the name of the source file so it is correctly referenced when we build the RPM.
Name: silex-app
Version: 1.4.5
# Source0 refers to silex-app-1.4.5.zip in SOURCES dir
Source0: %{name}-%{version}.zip
You can also define multiple source files such as Source1, Source2 etc.
%prep
%prep
# Unzip source file to BUILD dir
unzip %{SOURCE0}
Script command to 'prepare' (uncompress) the zip file to build it. Note that our silex-app-1.4.5.zip file will be unzipped to our BUILD dir when we build the RPM.
%build
Script commands to "build" the program (e.g. to compile it) and get it ready for installing. We're not doing that here.
%install
Here you are basically copying whatever you have in your %{_builddir} (BUILD dir) to %{buildroot}
What is the Buildroot? This was initially defined in the preamble section but it is best explained now.
This is best explained with an example. Say you want to install your source files in /opt/mypkgname/ and you also want a config file in /etc/mypkgname.conf. To achieve this you would do the following in the %install section:
%install
# Create the directory structure to mirror where the files are to be installed (when the RPM is installed) inside the Buildroot dir
# As per the definition in the preamble, Buildroot will be:
# /var/tmp/silex-app-1.4.5-buildroot
mkdir %{buildroot}
mkdir -p %{buildroot}/opt/mypkg
mkdir -p %{buildroot}/etc
# Copy files across from the BUILD dir to Buildroot
cp -r %{_builddir}/%{name}-%{version}/mypkg %{buildroot}/opt/mypkg
cp %{_builddir}/%{name}-%{version}/mypkg.conf %{buildroot}/etc/mypkg.conf
You are re-creating the tree that you want installed on your file system, with %{buildroot} as the equivalent of the target's root directory.
Hope that clears it up!
Now lets assume we have the following directory structure inside the silex-app dir:
|-- config
|-- src
|-- tests
|-- www
|-- composer.json
|-- composer.lock
When we build the RPM we want the www, src, test and the composer files copied to /var . Here's how you do it:
%install
mkdir %{buildroot}
mkdir -p -m0755 %{buildroot}/var/
cp -r %{_builddir}/%{name}-%{version}/www %{buildroot}/var/
cp -r %{_builddir}/%{name}-%{version}/src %{buildroot}/var/
cp -r %{_builddir}/%{name}-%{version}/tests %{buildroot}/var/
cp -r %{_builddir}/%{name}-%{version}/composer.* %{buildroot}/var/
%files Specifying all the files to be installed on the file system.
%files
# Set the permissions to the files/directories created
%defattr(-,apache,apache,-)
# Speicfy file/dir created
# Note that exact files must be specified so that when you remove the rpm those files/dirs are also removed
/var/www
/var/src
/var/tests
/var/composer.*
What is the %defattr attribute directive?
This allows setting of default attributes for files and directives.
Files and Directories
%defattr(<file mode>, <user>, <group>, <dir mode>)
What if I want to give different permissions to different files?
#%attr(<mode>, <user>, <group>) file
%attr(0644, root, root) /var/www/.htaccess
All of the directories, sub-directories and files will be installed to the file system when the RPM is installed.
Building the RPM
Now that the .spec file is complete, we can proceed to building the RPM.
Note: Don't forget to place your source file in the SOURCES dir and set the build area in the ~/.rpmmacros file!
Command to build the RPM:
rpmbuild -ba rpmbuild/SPECS/myappname.spec
If all goes well, your RPM will be available in the rpmbuild/RPMS dir.
Nuts and Bolts
Now that we have a basic idea of building RPMs, lets take a look at some of the more finer details.
Config Files
I found the following article quite useful to understand how the %config macro and its options work: Config file matrix