This documentation is for the latest stable (0.9.3) release of Fabric. To view documentation for the in-development (1.0) version, please click here.
The Fabric development team consists of two programmers, Jeff Forcier and Christian Vest Hansen, with Jeff taking the lead role. However, dozens of other developers pitch in by submitting patches and ideas, via individual emails, Redmine, the mailing list and GitHub.
Get the code¶
There are a number of ways to get involved with Fabric:
- Use Fabric and send us feedback! This is both the easiest and arguably the most important way to improve the project – let us know how you currently use Fabric and how you want to use it. (Please do try to search the ticket tracker first, though, when submitting feature ideas.)
- Report bugs. Pretty much a special case of the previous item: if you think you’ve found a bug in Fabric, check on the Redmine ticket tracker to see if anyone’s reported it yet, and if not – file a bug! If possible, try to make sure you can replicate it repeatedly, and let us know the circumstances (what version of Fabric you’re using, what platform you’re on, and what exactly you were doing when the bug cropped up.)
- Submit patches or new features. See the Source code checkouts documentation, grab a Git clone of the source, and either email a patch to the mailing list or make your own GitHub fork and post a link to your fork (or a specific commit on a fork) in the appropriate Redmine ticket. While we may not always reply promptly, we do try to make time eventually to inspect all contributions and either incorporate them or explain why we don’t feel the change is a good fit.
If a ticket-tracker ticket exists for a given issue, please keep all communication in that ticket’s comments – for example, when submitting patches via Github, it’s easier for us if you leave a note in the ticket instead of sending a Github pull request.
The core devs receive emails for just about any ticket-tracker activity, so additional notices via Github or other means only serve to slow things down.
Fabric tries hard to honor PEP-8, especially (but not limited to!) the following:
- Keep all lines under 80 characters. This goes for the ReST documentation as
well as code itself.
- Exceptions are made for situations where breaking a long string (such as a string being print-ed from source code, or an especially long URL link in documentation) would be kind of a pain.
- Typical Python 4-space (soft-tab) indents. No tabs! No 8 space indents! (No 2- or 3-space indents, for that matter!)
- CamelCase class names, but lowercase_underscore_separated everything else.
While Fabric’s development methodology isn’t set in stone yet, the following items detail how we currently organize the Git repository and expect to perform merges and so forth. This will be chiefly of interest to those who wish to follow a specific Git branch instead of released versions, or to any contributors.
- We use a combined ‘release and feature branches’ methodology, where every
minor release (e.g. 0.9, 1.0, 1.1, 1.2 etc; see Releases below for
details on versioning) gets a release branch for bugfixes, and big feature
development is performed in a central master branch and/or in
feature-specific feature branches (e.g. a branch for reworking the internals
to be threadsafe, or one for overhauling task dependencies, etc.)
- At time of writing, this means that Fabric maintains an 0.9 release branch, from which all prerelease and final release versions of 0.9.x, e.g. 0.9rc1 and 0.9.0 and so forth, are cut.
- New features intended for the next major release (Fabric 1.0) will be kept in the master branch. Once the 1.0 alpha or beta period begins, this work will be split off into a 1.0 branch and master will start forming Fabric 1.1.
- While we try our best not to commit broken code or change APIs without warning, as with many other open-source projects we can only have a guarantee of stability in the release branches. Only follow master if you’re willing to deal with a little pain.
- Conversely, because we try to keep release branches relatively stable, you may find it easier to use Fabric from a source checkout of a release branch instead of upgrading to new released versions. This can provide a decent middle ground between stability and the ability to get bugfixes or backported features easily.
- The core developers will take care of performing merging/branching on the official repositories. Since Git is Git, contributors may of course do whatever they wish in their own clones/forks.
- Bugfixes are to be performed on release branches and then merged into master so that master is always up-to-date (or nearly so; while it’s not mandatory to merge after every bugfix, doing so at least daily is a good idea.)
- Feature branches, if used, should periodically merge in changes from master so that when it comes time for them to merge back into master things aren’t quite as painful.
Fabric tries to follow open-source standards and conventions in its release tagging, including typical version numbers such as 2.0, 1.2.5, or 1.2b1. Each release will be marked as a tag in the Git repositories, and are broken down as follows:
Major releases update the first number, e.g. going from 0.9 to 1.0, and indicate that the software has reached some very large milestone.
For example, the upcoming 1.0 will mean that we feel Fabric has reached its primary design goals of a solid core API and well-defined area for additional functionality to live. Version 2.0 might, for example, indicate a rewrite using a new underlying network technology (though this isn’t necessarily planned.)
Major releases will often be backwards-incompatible with the previous line of development, though this is not a requirement, just a usual happenstance. Users should expect to have to make at least some changes to their fabfiles when switching between major versions.
Minor releases, such as moving from 1.0 to 1.1, typically mean that a new, large feature has been added. They are also sometimes used to mark off the fact that a lot of bug fixes or small feature modifications have occurred since the previous minor release. (And, naturally, some of them will involve both at the same time.)
These releases are guaranteed to be backwards-compatible with all other releases containing the same major version number, so a fabfile that works with 1.0 should also work fine with 1.1 or even 1.9.
This policy marks a departure from early versions of Fabric, wherein the minor release number was the backwards-compatibility boundary – e.g. Fabric 0.1 was incompatible with Fabric 0.0.x.
Fabric 0.1 to 0.9 also marked a rewrite of the software and a change of hands, and so did break backwards compatibility. This will not happen again.
The third and final part of version numbers, such as the ‘3’ in 1.0.3, generally indicate a release containing one or more bugfixes, although minor feature additions or modifications may sometimes occur.
This third number is sometimes omitted for the first major or minor release in a series, e.g. 1.2 or 2.0, and in these cases it can be considered an implicit zero (e.g. 2.0.0).
The 0.9.x branch of development will see more significant feature additions than is planned for future lines. This is in order to backport some useful features from the 1.0 branch so that the feature gap between 0.9 and 1.0 is not as large as it was when 0.9.0 was released.
In 1.0.x and so forth, tertiary releases are more likely to contain just bugfixes or tweaks, and not new functionality, as the window between minor releases is expected to be shorter than that of 0.1 => 0.9.
Support of older releases¶
Major and minor releases do not mark the end of the previous line or lines of development:
- The two most recent stable release branches will continue to receive critical bugfixes. For example, once 1.0 is released, both it and 0.9 will likely see tertiary releases until 1.1 is released, at which point only 1.1 and 1.0 will get bugfixes.
- Depending on the nature of bugs found and the difficulty in backporting them, older release lines may also continue to get bugfixes – but there’s no longer a guarantee of any kind. Thus, if a bug is found in 1.1 that affects 0.9 and can be easily applied, we may cut a new 0.9.x release.
- This policy may change in the future to accomodate more branches, depending on development speed.
We hope that this policy will allow us to have a rapid minor release cycle (and thus keep new features coming out frequently) without causing users to feel too much pressure to upgrade right away. At the same time, the backwards compatibility guarantee means that users should still feel comfortable upgrading to the next minor release in order to stay within this sliding support window.