Difference between revisions of "StarlingX/CentosToDebian"

Revision as of 15:39, 9 November 2021

Overview

The purpose of this wiki is to provide some guidance for converting a CentOS package to a Debian package.

CentOS Package Files

There are two main files which specify the CentOS build of a package:

build_srpm.data - Specifies the input sources for the build (both within and external to the package repository).
<packageName>.spec - Specification file which defines the package(s), dependencies, build rules and install rules.

These files are found in the "centos" directory which is generally a top-level directory in the root package directory. For example:

Repository: nfv
Package directory: nfv/nova-api-proxy
CentOS build directory: nfv/nova-api-proxy/centos

The "debian" build directory is a peer of the "centos" directory (i.e. nfv/nova-api-proxy/debian).

build_srpm.data

The build_srpm.data file defines the source inputs for the package build. The inputs may be files from the package repo itself, files from another repo or files from a download mirror.

The following variables are commonly used for these inputs:

CGCS_BASE - An import mirror (/import/mirrors/starlingx).
PKG_BASE - The root package directory.
STX_BASE - The root directory for all StarlingX repositories.

Specification File

The specification file drives the CentOS package build. It contains two main sections:

Preamble - Defines metadata for the build.
Body - Contains the build instructions.

The following table describes the commonly used fields (SPEC directives) in the specification file.

Directive	Type	Description
Summary	Preamble	A brief description of the package.
Name	Preamble	The name of the package.
Version	Preamble	The current version of the package.
Source*	Preamble	Specifies a source file for the build.
BuildRequires	Preamble	Specifies a dependency for the package.
Requires	Preamble	Specifies a dependency for the package.
%package	Body	Defines an RPM file to be built. This is used if multiple RPMs are built from the SPEC file.
%description	Body	A detailed description of the package
%prep	Body	Steps for preparing the software to be built. This might include extracting a tar file of upstream source code, for example.
%build	Body	Specifies the rules to build the software of the package.
%install	Body	Specifies the install rules for the package. Files are copied from the build directory to the directory structure containing the files to be installed.
%files	Body	Defines the files to be installed on a a system when the package is installed

Mapping a CentOS Specification file to Debian Build Files

The following table shows at a high level how to map sections of Centos .spec

@@ Line 39: / Line 39: @@
 ! Directive !! Type !! Description
 |-
-| Summary || Preamble || A brief description of the package
+| Summary || Preamble || A brief description of the package.
 |-
-| Example || Example || Example
+| Name || Preamble || The name of the package.
 |-
-| Example || Example || Example
+| Version || Preamble || The current version of the package.
 |-
-| Example || Example || Example
+| Source* || Preamble || Specifies a source file for the build.
 |-
-| Example || Example || Example
+| BuildRequires || Preamble || Specifies a dependency for the package.
 |-
-| Example || Example || Example
+| Requires || Preamble || Specifies a dependency for the package.
 |-
-| Example || Example || Example
+| %package || Body || Defines an RPM file to be built. This is used if multiple RPMs are built from the SPEC file.
 |-
-| Example || Example || Example
+| %description  || Body || A detailed description of the package
 |-
-| Example || Example || Example
+| %prep || Body || Steps for preparing the software to be built. This might include extracting a tar file of upstream source code, for example.
 |-
-| Example || Example || Example
+| %build  || Body || Specifies the rules to build the software of the package.
 |-
-| Example || Example || Example
+| %install || Body || Specifies the install rules for the package. Files are copied from the build directory to the directory structure containing the files to be installed.
 |-
-| Example || Example || Example
+| %files || Body ||Defines the files to be installed on a a system when the package is installed
-|-
-| Example || Example || Example
 |}
+== Mapping a CentOS Specification file to Debian Build Files ==
+The following table shows at a high level how to map sections of Centos .spec