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pkgcenter (pronounced "package center") is a cross-platform framework for creating and/or remastering native packages for NetBSD, FreeBSD, and RedHat/CentOS Linux.

Foreword

The following is required before using git commit in this project.

$ .git-hooks/install.sh

This will ensure the FrauBSD keyword is expanded/updated for each commit.

Introduction

If you write software and like to share it, you may be interested in the topic of software packaging.

Software packaging frameworks commonly come in two flavors:

  1. Native
  2. 3rd-party

Some exampes of Native frameworks:

Platform Name Install Tool
NetBSD pkgsrc* pkg_add or pkgin
FreeBSD ports pkg
RedHat/CentOS Linux rpm rpm or yum
Mac OS X App Store App Store.app
Debian/Ubuntu Linux Aptitude dpkg or apt-get

* Framework has been released for additional platforms but is Native on listed platform.

Some examples of 3rd-party frameworks:

Platform Name Install Tool
Mac OS X homebrew brew
Mac OS X MacPorts port
Node.js Node Package Manager npm
Python PIP Installs Packages pip

pkgcenter is a unique framework that blends the above "3rd-party" and "native" categories to produce a new type -- a framework that is 3rd-party but targets native install tools.

Using native frameworks to generate packages:

NetBSD FreeBSD RedHat/CentOS Linux
Input pkgsrc Makefile ports Makefile *.src.rpm
Build Tool pkg_create pkg rpmbuild
Output *.tgz *.txz *.rpm
Install Tool pkg_add or pkgin pkg rpm

Using pkgcenter to generate packages:

NetBSD FreeBSD RedHat/CentOS Linux
Input pkgcenter Makefile pkgcenter Makefile pkgcenter Makefile
Build Tool tar tar rpmbuild
Output *.tgz *.txz *.rpm
Install Tool pkg_add or pkgin pkg rpm

The output and install tools above do not differ. Only the input and build method changes to become more cross-platform compatible.

pkgcenter has been tested successfully to work with:

pkgsrc ports pkgcenter
[b]make (NetBSD) X X X
[b]make (FreeBSD) X X X
[f]make (FreeBSD) X
make (GNU/Linux) X
make (Mac OS X) X

Using the following flavors of UNIX shell:

  • Linux Bourn Again SHell (bash-4.x)
  • Apple Mac OS X shell (bash-3.x)
  • Debian Almquist SHell (dash)
  • FreeBSD bourne shell (sh)

NetBSD/FreeBSD packages are built with tar and RPM packages are built with rpmbuild (but you do not need a source RPM file to build one).

Unlike pkgsrc from NetBSD and ports from FreeBSD which focus on:

  • Acquisition
  • Compilation
  • Installation
  • Packaging

pkgcenter instead focuses on:

  • Versioning
  • Auditing
  • Packaging

By not strictly controlling the process of acquisition and compilation, a wider variety of software can be packaged. The package framework does not need to be taught how to acquire/compile software each time a new transport/compilation method is developed.

By relying on the native package managers for installation, the package framework does not need to know how to install the package, only how to re/create it.

While it can be said that pkgsrc, ports, and pkgcenter all use a system of Makefiles and shell scripts, only pkgcenter is cross-platform compatible and agnostic to make and sh flavor.

Versioning

One of the problems with frameworks such as pkgsrc and ports is the way pre-packaged metadata is stored.

The metadata for the final output (*.tgz for pkgsrc and *.txz for ports) is stored in the framework Makefile. This means every time the format of the Makefile is changed, the metadata may potentially have to be updated to conform to the new syntax in the framework.

For example, games/an/Makefile contains a COMMENT variable which sets the one-line description of the software. This is an example of metadata which gets compiled into the package. In NetBSD the comment is put inside a file named +COMMENT at the top-level of the tar archive while FreeBSD puts it in the +MANIFEST and +COMPACT_MANIFEST files.

If the framework is changed to instead change the variable "COMMENT" to "BLURB" it would require changing each/every Makefile.

In pkgcenter, no such change would ever be required because the metadata is not stored in the Makefile but instead in the final output format.

For a NetBSD package, the one-line description is stored in the +COMMENT file where it will ultimately end-up and for a FreeBSD package it is in the precompiled MANIFEST where it belongs.

There is no need to chase framework changes in each software entry because the metadata is in a format that gets as close to the finalized product as possible.

Changes to software entries are only required if the format expected by the install tool changes.

Frameworks tend to iterate change faster than the tool used to install packages built by said framework.

Auditing

Since the metadata only changes when the install tool changes, it becomes easier to track entry-specific changes using version control tags.

pkgcenter supports version control software such as CVS, Perforce, and Git.

In the SPECFILE for RPMs, MANIFEST for FreeBSD packages, and PLIST for NetBSD packages are all the metadata necessary to determine the shipping package version. Unique to pkgcenter is the ability to say "make tag" (or "make label" for perforce users) to produce a tag for the current state of tree that produced the package.

Making it easier to audit old code, you can freely backup to a previous state of the tree to produce an exact version.

The ability to fast-forward and rewind the version-control system that the framework lives within is supposed to be an inherited trait but as many have found, pkgsrc and ports are not designed to work that way.

In reality, you run into serious problems when you try and rewind pkgsrc/ports to a previous state to produce an old package:

  • DISTSITE may no longer be available
  • Mk files may become misaligned with software entry Makefile
  • Mk files too old to produce a working package
  • pkg (FreeBSD) or pkg_create (NetBSD) too old/new
  • Dependent software entries misaligned

None of these issues affect pkgcenter.

The Makefile for every software entry in pkgcenter is byte-for-byte the same. Any/all changes to the framework itself never touch any file containing metadata.

These are just some of the ways that pkgcenter improves on audit abilities for package frameworks.