(WIP) content.rst

content.rst

@@ -0,0 +1,99 @@
+Why Buildbot
+============
+
+What purpose does Buildbot serve?  When would I want to use it?
+
+Buildbot is a framework for automating build, test, and release processes.
+It's used for continuous integration, continuous deployment, and release management.
+
+Building
+--------
+
+Building means compiling, minifying, linking and generally producing what you need to actually run the app from the source code.
+You want this process to be automated and repeatable, so that you can eliminate variation in the build process or environment as a cause of different behavior.
+This is particularly important in CD - shipping an RPM accidentally built on the wrong version of CentOS to all of your production servers would be very painful.
+At Mozilla, we build for lots and lots of platforms - more than we could expect any one developer to maintain - and each build can take a very long time.
+So automation, and parallelism, is critical to getting results in a reasonable (but still very long) amount of time.
+Open source projects generally support multiple operating systems or environments, and more often those platforms are maintained by one or two project members.
+Automating builds on those platforms allows everyone to be confident their change hasn't broken a platform they don't normally use.
+
+Testing
+-------
+
+Testing means running test suites of all sorts - unit, acceptance, regression, integration.
+Agile best practices tell us to integrate constantly and run tests all the time.
+For a small project, developers can do this themselves, but new contributors usually won't.
+Test suites get longer, and especially integration and acceptance tests tend to be slow.
+Tests, even for platform-agnostic projects, tend to show failures on different platforms.
+At Mozilla, we have a lot of tests, and a lot of platforms and builds to run them on.
+The build and tests for a single commit can add up to hundreds of hours.
+Obviously, then, parallelism is important!
+
+Releasing
+---------
+
+Release processes include packaging software to ship to customers, and the deployment phase of continuous deployment.
+Like building and testing, automating release processes gives predictability and repeatability.
+Just like testing the software, performing releases frequently (even if the results aren't actually shipped) helps to tease out bugs that will otherwise affect customers or make schedules slip.
+For open-source projects, automating the release process also tends to allow more releases: it's usually at least a few hours' work to ship a release by hand, so busy project maintainers tend to put off releases in favor of other work on the project.
+At Mozilla, the release process involves a lot more than building RPMs and DMGs: tagging, localization, QA, signing, MAR generation, update snippets, and much more are all handled automatically.
+This has drastically shortened the end-to-end time required to make a release, and reduced the chances for human error along the way.
+
+Framework
+---------
+
+TODO
+
+Other Tools
+-----------
+
+Buildbot is by no means the only tool in this space.
+
+I'll talk a little about the other options here, but my focus is on Buildbot itself, so I don't spend a lot of time making comparisons.
+If other tools suit a particular purpose better than Buildbot, then by all means use them.
+
+Tinderbox
+.........
+
+Long-time Mozillians may remember Tinderbox; some even fondly!
+Tinderbox uses a "push" model, and takes the "continous" in continuous integration literally.
+Each host builds the software in a loop, updating to the most recent version at the beginning of each iteration.
+The hosts email the logs to a central tinderbox server for display.
+Thus the central server has no way to control what gets built -- or what does not.
+
+Jenkins
+.......
+
+Jenkins, formerly Hudson, is a very popular open source, web-based CI tool.
+It supports configuration via the web interface, and by default performs tasks on a single host.
+It is massively extensible with a wide variety of plugins, although the system is Java so it's not trivial to write or modify such plugins.
+As such, if you have relatively simple requirements that are supported by Jenkins and its plugins, then Jenkins is very easy to set up.
+However, the difficulty increases quickly for unusual or complex requirements.
+
+CruiseControl
+.............
+
+TODO
+
+Travis-CI
+.........
+
+TODO
+
+Buildbot's Concepts
+===================
+
+For any application, it's important to understand the underlying conceptual model to use the tool effectively.
+As a framework, Buildbot brings a certain conceptual model, but allows users to customize the pieces of that model to suit the requirements
+
+
+
+Using Buildbot
+==============
+
+TODO
+
+Running Buildbot
+================
+
+TODO