- Where should I ask questions or make suggestions?
The tpkg-users mailing list
- Surely this already exists?
Despite extensive searching we couldn't find an existing project that was close enough to what we had in mind. We know of a few large companies that have similar tools internally, but they have not released the tools as open source.
We considered using an existing, widely used packaging and deployment system like dpkg/apt or rpm/yum, but decided that was not ideal for a couple of reasons. One of our requirements is a packaging environment that is separate from the operating system packaging environment for the reasons giving in the introduction. While it is possible to run multiple instances of, for example, rpm on the same box that is generally a recipe for confusion and errors: "Oh, I see the problem, you used /usr/bin/rpm instead of /opt/local/bin/rpm."
We also considered swbis, a GNU project which implements a POSIX packaging standard. That project has the advantage (for our purposes) of not being a widely used OS packaging tool, but on the flip side is much less widely used and less well developed.
- What platforms does it work on?
Most common forms on Unix should work. You need Ruby, the facter library (available via rubygems), and GNU or BSD tar. It is known to work on Red Hat Enterprise Linux, CentOS, Debian, Ubuntu, FreeBSD and Solaris. It has also been lightly tested on Windows under cygwin.
- What is the package format?
A tarball with a particular directory structure and a YAML metadata file. At runtime tpkg will search your path for a modern version of tar (bsdtar or GNU tar for example) so that long filenames are supported. See the tpkg internals documentation for more information.
- Why tar?
The two widely available and commonly used file archiving formats are tar and zip. There are other formats like cpio that are commonly available on Unix but less so on Windows. Tar and zip both have advantages and disadvantages. Tar has native support for Unix permissions and is more likely to be installed on even a minimal Unix install than the zip utilities. On the negative side for tar are the lack of support for random access within the archive and a handful of different standards for modern archive formats that support longer filenames, etc. In the end the more "unixy" tar was selected.
- Why use tpkg instead of Capistrano or Vlad the Deployer?
Tpkg provides many features not available in cap or vlad. File encryption is essential for deploying the database.yml file in Rails apps, along with any SSL keys needed. Rails, via bundler, provides support for installing gem dependencies, but tpkg can handle any kind of dependency, so you can pull in nginx or Apache, MySQL, or other non-gem dependencies. Tpkg's externals support can tie into an OS config management system to configure accounts or other OS settings required by your application. Init script support in tpkg means you can easily have your application start at system boot time. A logrotate package is available for easy log rotation. All of these features could be implemented in your cap or vlad configuration, but standard implementations are not readily available and your implementation has to be cut-n-pasted or otherwise separately maintained if you have multiple projects.
- How do I specify a version number during install/remove/upgrade?
Use the following syntax:
tpkg -i testpkg=2.4=4
The package version is optional, so if any package version of testpkg 2.4 is acceptable, or testpkg doesn't have package versions, then this syntax will work:
tpkg -i testpkg=2.4
Inequalities (<=, >=) are also supported. This syntax was partially borrowed from apt-get.
- How do I downgrade a package to an older version?
- Are there pre-built packages for common applications like Ruby, Perl or Apache?
- Does tpkg ignore .svn/.git/etc. when making a package?
No. The primary reason (in the case of svn users at least) is to encourage users to build packages from an svn export rather than a working copy. This helps ensure that packages are not accidentally built with uncommitted changes. By using an export from svn you know your package only includes files under revision control.
- Does tpkg work on Windows?
- Why is it called tpkg?
We wanted a meaningful name so that folks who don't work with tpkg on a regular basis, like project managers, have an easier time remembering the name. For tpkg that meant variants of pack, package, inst, install, etc. We settled on pkg as short, easily typed, etc. Most of the <one letter>pkg names were already taken by other projects, mostly package managers for little specialized Linux distros. tpkg and a few others were available, and tpkg seemed the easiest of those to say and remember.
You can use the --downgrade option of tpkg. For example, if you want to downgrade your pkg fubar to version 1.1, package version 2, run one of the following commands.
If the package is in the repository:
If you have the package file locally: