Add documentation.

Change-Id: I8197ec2e52596fa4136f8af9aa93ea06e56d4d0d

.gitignore

@@ -4,3 +4,6 @@ zuul.egg-info
 MANIFEST
 .tox
 *.pyc
+doc/build
+doc/source/sourcecode
+*~

doc/Makefile

@@ -0,0 +1,153 @@
+# Makefile for Sphinx documentation
+#
+
+# You can set these variables from the command line.
+SPHINXOPTS    =
+SPHINXBUILD   = sphinx-build
+PAPER         =
+BUILDDIR      = build
+
+# Internal variables.
+PAPEROPT_a4     = -D latex_paper_size=a4
+PAPEROPT_letter = -D latex_paper_size=letter
+ALLSPHINXOPTS   = -d $(BUILDDIR)/doctrees $(PAPEROPT_$(PAPER)) $(SPHINXOPTS) source
+# the i18n builder cannot share the environment and doctrees with the others
+I18NSPHINXOPTS  = $(PAPEROPT_$(PAPER)) $(SPHINXOPTS) source
+
+.PHONY: help clean html dirhtml singlehtml pickle json htmlhelp qthelp devhelp epub latex latexpdf text man changes linkcheck doctest gettext
+
+help:
+	@echo "Please use \`make <target>' where <target> is one of"
+	@echo "  html       to make standalone HTML files"
+	@echo "  dirhtml    to make HTML files named index.html in directories"
+	@echo "  singlehtml to make a single large HTML file"
+	@echo "  pickle     to make pickle files"
+	@echo "  json       to make JSON files"
+	@echo "  htmlhelp   to make HTML files and a HTML help project"
+	@echo "  qthelp     to make HTML files and a qthelp project"
+	@echo "  devhelp    to make HTML files and a Devhelp project"
+	@echo "  epub       to make an epub"
+	@echo "  latex      to make LaTeX files, you can set PAPER=a4 or PAPER=letter"
+	@echo "  latexpdf   to make LaTeX files and run them through pdflatex"
+	@echo "  text       to make text files"
+	@echo "  man        to make manual pages"
+	@echo "  texinfo    to make Texinfo files"
+	@echo "  info       to make Texinfo files and run them through makeinfo"
+	@echo "  gettext    to make PO message catalogs"
+	@echo "  changes    to make an overview of all changed/added/deprecated items"
+	@echo "  linkcheck  to check all external links for integrity"
+	@echo "  doctest    to run all doctests embedded in the documentation (if enabled)"
+
+clean:
+	-rm -rf $(BUILDDIR)/*
+
+html:
+	$(SPHINXBUILD) -b html $(ALLSPHINXOPTS) $(BUILDDIR)/html
+	@echo
+	@echo "Build finished. The HTML pages are in $(BUILDDIR)/html."
+
+dirhtml:
+	$(SPHINXBUILD) -b dirhtml $(ALLSPHINXOPTS) $(BUILDDIR)/dirhtml
+	@echo
+	@echo "Build finished. The HTML pages are in $(BUILDDIR)/dirhtml."
+
+singlehtml:
+	$(SPHINXBUILD) -b singlehtml $(ALLSPHINXOPTS) $(BUILDDIR)/singlehtml
+	@echo
+	@echo "Build finished. The HTML page is in $(BUILDDIR)/singlehtml."
+
+pickle:
+	$(SPHINXBUILD) -b pickle $(ALLSPHINXOPTS) $(BUILDDIR)/pickle
+	@echo
+	@echo "Build finished; now you can process the pickle files."
+
+json:
+	$(SPHINXBUILD) -b json $(ALLSPHINXOPTS) $(BUILDDIR)/json
+	@echo
+	@echo "Build finished; now you can process the JSON files."
+
+htmlhelp:
+	$(SPHINXBUILD) -b htmlhelp $(ALLSPHINXOPTS) $(BUILDDIR)/htmlhelp
+	@echo
+	@echo "Build finished; now you can run HTML Help Workshop with the" \
+	      ".hhp project file in $(BUILDDIR)/htmlhelp."
+
+qthelp:
+	$(SPHINXBUILD) -b qthelp $(ALLSPHINXOPTS) $(BUILDDIR)/qthelp
+	@echo
+	@echo "Build finished; now you can run "qcollectiongenerator" with the" \
+	      ".qhcp project file in $(BUILDDIR)/qthelp, like this:"
+	@echo "# qcollectiongenerator $(BUILDDIR)/qthelp/Zuul.qhcp"
+	@echo "To view the help file:"
+	@echo "# assistant -collectionFile $(BUILDDIR)/qthelp/Zuul.qhc"
+
+devhelp:
+	$(SPHINXBUILD) -b devhelp $(ALLSPHINXOPTS) $(BUILDDIR)/devhelp
+	@echo
+	@echo "Build finished."
+	@echo "To view the help file:"
+	@echo "# mkdir -p $$HOME/.local/share/devhelp/Zuul"
+	@echo "# ln -s $(BUILDDIR)/devhelp $$HOME/.local/share/devhelp/Zuul"
+	@echo "# devhelp"
+
+epub:
+	$(SPHINXBUILD) -b epub $(ALLSPHINXOPTS) $(BUILDDIR)/epub
+	@echo
+	@echo "Build finished. The epub file is in $(BUILDDIR)/epub."
+
+latex:
+	$(SPHINXBUILD) -b latex $(ALLSPHINXOPTS) $(BUILDDIR)/latex
+	@echo
+	@echo "Build finished; the LaTeX files are in $(BUILDDIR)/latex."
+	@echo "Run \`make' in that directory to run these through (pdf)latex" \
+	      "(use \`make latexpdf' here to do that automatically)."
+
+latexpdf:
+	$(SPHINXBUILD) -b latex $(ALLSPHINXOPTS) $(BUILDDIR)/latex
+	@echo "Running LaTeX files through pdflatex..."
+	$(MAKE) -C $(BUILDDIR)/latex all-pdf
+	@echo "pdflatex finished; the PDF files are in $(BUILDDIR)/latex."
+
+text:
+	$(SPHINXBUILD) -b text $(ALLSPHINXOPTS) $(BUILDDIR)/text
+	@echo
+	@echo "Build finished. The text files are in $(BUILDDIR)/text."
+
+man:
+	$(SPHINXBUILD) -b man $(ALLSPHINXOPTS) $(BUILDDIR)/man
+	@echo
+	@echo "Build finished. The manual pages are in $(BUILDDIR)/man."
+
+texinfo:
+	$(SPHINXBUILD) -b texinfo $(ALLSPHINXOPTS) $(BUILDDIR)/texinfo
+	@echo
+	@echo "Build finished. The Texinfo files are in $(BUILDDIR)/texinfo."
+	@echo "Run \`make' in that directory to run these through makeinfo" \
+	      "(use \`make info' here to do that automatically)."
+
+info:
+	$(SPHINXBUILD) -b texinfo $(ALLSPHINXOPTS) $(BUILDDIR)/texinfo
+	@echo "Running Texinfo files through makeinfo..."
+	make -C $(BUILDDIR)/texinfo info
+	@echo "makeinfo finished; the Info files are in $(BUILDDIR)/texinfo."
+
+gettext:
+	$(SPHINXBUILD) -b gettext $(I18NSPHINXOPTS) $(BUILDDIR)/locale
+	@echo
+	@echo "Build finished. The message catalogs are in $(BUILDDIR)/locale."
+
+changes:
+	$(SPHINXBUILD) -b changes $(ALLSPHINXOPTS) $(BUILDDIR)/changes
+	@echo
+	@echo "The overview file is in $(BUILDDIR)/changes."
+
+linkcheck:
+	$(SPHINXBUILD) -b linkcheck $(ALLSPHINXOPTS) $(BUILDDIR)/linkcheck
+	@echo
+	@echo "Link check complete; look for any errors in the above output " \
+	      "or in $(BUILDDIR)/linkcheck/output.txt."
+
+doctest:
+	$(SPHINXBUILD) -b doctest $(ALLSPHINXOPTS) $(BUILDDIR)/doctest
+	@echo "Testing of doctests in the sources finished, look at the " \
+	      "results in $(BUILDDIR)/doctest/output.txt."

doc/source/conf.py

@@ -0,0 +1,244 @@
+# -*- coding: utf-8 -*-
+#
+# Zuul documentation build configuration file, created by
+# sphinx-quickstart on Fri Jun  8 14:44:26 2012.
+#
+# This file is execfile()d with the current directory set to its containing dir.
+#
+# Note that not all possible configuration values are present in this
+# autogenerated file.
+#
+# All configuration values have a default; values that are commented out
+# serve to show the default.
+
+import sys, os
+
+# If extensions (or modules to document with autodoc) are in another directory,
+# add these directories to sys.path here. If the directory is relative to the
+# documentation root, use os.path.abspath to make it absolute, like shown here.
+#sys.path.insert(0, os.path.abspath('.'))
+
+# -- General configuration -----------------------------------------------------
+
+# If your documentation needs a minimal Sphinx version, state it here.
+#needs_sphinx = '1.0'
+
+# Add any Sphinx extension module names here, as strings. They can be extensions
+# coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
+extensions = ['sphinx.ext.intersphinx']
+
+intersphinx_mapping = {'python': ('http://docs.python.org/2.7', None)}
+
+# Add any paths that contain templates here, relative to this directory.
+templates_path = ['_templates']
+
+# The suffix of source filenames.
+source_suffix = '.rst'
+
+# The encoding of source files.
+#source_encoding = 'utf-8-sig'
+
+# The master toctree document.
+master_doc = 'index'
+
+# General information about the project.
+project = u'Zuul'
+copyright = u'2012, OpenStack'
+
+# The version info for the project you're documenting, acts as replacement for
+# |version| and |release|, also used in various other places throughout the
+# built documents.
+#
+# The short X.Y version.
+version = '1.0'
+# The full version, including alpha/beta/rc tags.
+release = '1.0'
+
+# The language for content autogenerated by Sphinx. Refer to documentation
+# for a list of supported languages.
+#language = None
+
+# There are two options for replacing |today|: either, you set today to some
+# non-false value, then it is used:
+#today = ''
+# Else, today_fmt is used as the format for a strftime call.
+#today_fmt = '%B %d, %Y'
+
+# List of patterns, relative to source directory, that match files and
+# directories to ignore when looking for source files.
+exclude_patterns = []
+
+# The reST default role (used for this markup: `text`) to use for all documents.
+#default_role = None
+
+# If true, '()' will be appended to :func: etc. cross-reference text.
+#add_function_parentheses = True
+
+# If true, the current module name will be prepended to all description
+# unit titles (such as .. function::).
+#add_module_names = True
+
+# If true, sectionauthor and moduleauthor directives will be shown in the
+# output. They are ignored by default.
+#show_authors = False
+
+# The name of the Pygments (syntax highlighting) style to use.
+pygments_style = 'sphinx'
+
+# A list of ignored prefixes for module index sorting.
+#modindex_common_prefix = []
+
+
+# -- Options for HTML output ---------------------------------------------------
+
+# The theme to use for HTML and HTML Help pages.  See the documentation for
+# a list of builtin themes.
+html_theme = 'default'
+
+# Theme options are theme-specific and customize the look and feel of a theme
+# further.  For a list of options available for each theme, see the
+# documentation.
+#html_theme_options = {}
+
+# Add any paths that contain custom themes here, relative to this directory.
+#html_theme_path = []
+
+# The name for this set of Sphinx documents.  If None, it defaults to
+# "<project> v<release> documentation".
+#html_title = None
+
+# A shorter title for the navigation bar.  Default is the same as html_title.
+#html_short_title = None
+
+# The name of an image file (relative to this directory) to place at the top
+# of the sidebar.
+#html_logo = None
+
+# The name of an image file (within the static path) to use as favicon of the
+# docs.  This file should be a Windows icon file (.ico) being 16x16 or 32x32
+# pixels large.
+#html_favicon = None
+
+# Add any paths that contain custom static files (such as style sheets) here,
+# relative to this directory. They are copied after the builtin static files,
+# so a file named "default.css" will overwrite the builtin "default.css".
+html_static_path = ['_static']
+
+# If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
+# using the given strftime format.
+#html_last_updated_fmt = '%b %d, %Y'
+
+# If true, SmartyPants will be used to convert quotes and dashes to
+# typographically correct entities.
+#html_use_smartypants = True
+
+# Custom sidebar templates, maps document names to template names.
+#html_sidebars = {}
+
+# Additional templates that should be rendered to pages, maps page names to
+# template names.
+#html_additional_pages = {}
+
+# If false, no module index is generated.
+#html_domain_indices = True
+
+# If false, no index is generated.
+#html_use_index = True
+
+# If true, the index is split into individual pages for each letter.
+#html_split_index = False
+
+# If true, links to the reST sources are added to the pages.
+#html_show_sourcelink = True
+
+# If true, "Created using Sphinx" is shown in the HTML footer. Default is True.
+#html_show_sphinx = True
+
+# If true, "(C) Copyright ..." is shown in the HTML footer. Default is True.
+#html_show_copyright = True
+
+# If true, an OpenSearch description file will be output, and all pages will
+# contain a <link> tag referring to it.  The value of this option must be the
+# base URL from which the finished HTML is served.
+#html_use_opensearch = ''
+
+# This is the file name suffix for HTML files (e.g. ".xhtml").
+#html_file_suffix = None
+
+# Output file base name for HTML help builder.
+htmlhelp_basename = 'Zuuldoc'
+
+
+# -- Options for LaTeX output --------------------------------------------------
+
+latex_elements = {
+# The paper size ('letterpaper' or 'a4paper').
+#'papersize': 'letterpaper',
+
+# The font size ('10pt', '11pt' or '12pt').
+#'pointsize': '10pt',
+
+# Additional stuff for the LaTeX preamble.
+#'preamble': '',
+}
+
+# Grouping the document tree into LaTeX files. List of tuples
+# (source start file, target name, title, author, documentclass [howto/manual]).
+latex_documents = [
+  ('index', 'Zuul.tex', u'Zuul Documentation',
+   u'OpenStack', 'manual'),
+]
+
+# The name of an image file (relative to this directory) to place at the top of
+# the title page.
+#latex_logo = None
+
+# For "manual" documents, if this is true, then toplevel headings are parts,
+# not chapters.
+#latex_use_parts = False
+
+# If true, show page references after internal links.
+#latex_show_pagerefs = False
+
+# If true, show URL addresses after external links.
+#latex_show_urls = False
+
+# Documents to append as an appendix to all manuals.
+#latex_appendices = []
+
+# If false, no module index is generated.
+#latex_domain_indices = True
+
+
+# -- Options for manual page output --------------------------------------------
+
+# One entry per manual page. List of tuples
+# (source start file, name, description, authors, manual section).
+man_pages = [
+    ('index', 'zuul', u'Zuul Documentation',
+     [u'OpenStack'], 1)
+]
+
+# If true, show URL addresses after external links.
+#man_show_urls = False
+
+
+# -- Options for Texinfo output ------------------------------------------------
+
+# Grouping the document tree into Texinfo files. List of tuples
+# (source start file, target name, title, author,
+#  dir menu entry, description, category)
+texinfo_documents = [
+  ('index', 'Zuul', u'Zuul Documentation',
+   u'OpenStack', 'Zuul', 'One line description of project.',
+   'Miscellaneous'),
+]
+
+# Documents to append as an appendix to all manuals.
+#texinfo_appendices = []
+
+# If false, no module index is generated.
+#texinfo_domain_indices = True
+
+# How to display URL addresses: 'footnote', 'no', or 'inline'.
+#texinfo_show_urls = 'footnote'

doc/source/gating.rst

@@ -0,0 +1,96 @@
+:title: Project Gating
+
+Project Gating
+==============
+
+Traditionally, many software development projects merge changes from
+developers into the repository, and then identify regressions
+resulting from those changes (perhaps by running a test suite with a
+continuous integration system such as Jenkins), followed by more
+patches to fix those bugs.  When the mainline of development is
+broken, it can be very frustrating for developers and can cause lost
+productivity, particularly so when the number of contributors or
+contributions is large.
+
+The process of gating attempts to prevent changes that introduce
+regressions from being merged.  This keeps the mainline of development
+open and working for all developers, and only when a change is
+confirmed to work without disruption is it merged.
+
+Many projects practice an informal method of gating where developers
+with mainline commit access ensure that a test suite runs before
+merging a change.  With more developers, more changes, and more
+comprehensive test suites, that process does not scale very well, and
+is not the best use of a developer's time.  Zuul can help automate
+this process, with a particular emphasis on ensuring large numbers of
+changes are tested correctly.
+
+Zuul was designed to handle the workflow of the OpenStack project, but
+can be used with any project.
+
+A particular focus of Zuul is ensuring correctly ordered testing of
+changes in parallel.  A gating system should always test each change
+applied to the tip of the branch exactly as it is going to be merged.
+A simple way to do that would be to test one change at a time, and
+merge it only if it passes tests.  That works very well, but if
+changes take a long time to test, developers may have to wait a long
+time for their changes to make it into the repository.  With some
+projects, it may take hours to test changes, and it is easy for
+developers to create changes at a rate faster than they can be tested
+and merged.
+
+Zuul's DependentQueueManager allows for parallel execution of test
+jobs for gating while ensuring changes are tested correctly, exactly
+as if they had been tested one at a time.  It does this by performing
+speculative execution of test jobs; it assumes that all jobs will
+succeed and tests them in parallel accordingly.  If they do succeed,
+they can all be merged.  However, if one fails, then changes that were
+expecting it to succeed are re-tested without the failed change.  In
+the best case, as many changes as execution contexts are available may
+be tested in parallel and merged at once.  In the worst case, changes
+are tested one at a time (as each subsequent change fails, changes
+behind it start again).  In practice, the OpenStack project observes
+something closer to the best case.
+
+For example, if a core developer approves five changes in rapid
+succession::
+
+  A, B, C, D, E
+
+Zuul queues those changes in the order they were approved, and notes
+that each subsequent change depends on the one ahead of it merging::
+
+  A <-- B <-- C <-- D <-- E
+
+Zuul then starts immediately testing all of the changes in parallel.
+But in the case of changes that depend on others, it instructs the
+test system to include the changes ahead of it, with the assumption
+they pass.  That means jobs testing change *B* include change *A* as
+well::
+
+  Jobs for A: merge change A, then test
+  Jobs for B: merge changes A and B, then test
+  Jobs for C: merge changes A, B and C, then test
+  Jobs for D: merge changes A, B, C and D, then test
+  Jobs for E: merge changes A, B, C, D and E, then test
+
+If changes *A* and *B* pass tests, and *C*, *D*, and *E* fail::
+
+  A[pass] <-- B[pass] <-- C[fail] <-- D[fail] <-- E[fail]
+
+Zuul will merge change *A* followed by change *B*, leaving this queue::
+
+  C[fail] <-- D[fail] <-- E[fail]
+
+Since *D* was dependent on *C*, it is not clear whether *D*'s failure is the
+result of a defect in *D* or *C*::
+
+  C[fail] <-- D[unknown] <-- E[unknown]
+
+Since *C* failed, it will report the failure and drop *C* from the queue::
+
+  D[unknown] <-- E[unknown]
+
+This queue is the same as if two new changes had just arrived, so Zuul
+starts the process again testing *D* against the tip of the branch, and
+*E* against *D*.

doc/source/index.rst

@@ -0,0 +1,32 @@
+.. Zuul documentation master file, created by
+   sphinx-quickstart on Fri Jun  8 14:44:26 2012.
+   You can adapt this file completely to your liking, but it should at least
+   contain the root `toctree` directive.
+
+Zuul - A Project Gating System
+==============================
+
+Zuul is a program that is used to gate the source code repository of a
+project so that changes are only merged if they pass tests.
+
+The main component of Zuul is the scheduler.  It receives events
+related to proposed changes (currently from Gerrit), triggers tests
+based on those events (currently on Jenkins), and reports back.
+
+Contents:
+
+.. toctree::
+   :maxdepth: 2
+
+   gating
+   triggers
+   launchers
+   zuul
+
+Indices and tables
+==================
+
+* :ref:`genindex`
+* :ref:`modindex`
+* :ref:`search`
+

doc/source/launchers.rst

@@ -0,0 +1,105 @@
+:title: Launchers
+
+Launchers
+=========
+
+Zuul has a modular architecture for launching jobs.  Currently only
+Jenkins is supported, but it should be fairly easy to add a module to
+support other systems.  Zuul makes very few assumptions about the
+interface to a launcher -- if it can trigger jobs, cancel them, and
+receive success or failure reports, it should be able to be used with
+Zuul.  Patches to this effect are welcome.
+
+Jenkins
+-------
+
+Zuul works with Jenkins using the Jenkins API and the notification
+module.  It uses the Jenkins API to trigger jobs, passing in
+parameters indicating what should be tested.  It recieves
+notifications on job completion via the notification API (so jobs must
+be conifigured to notify Zuul).
+
+Jenkins Configuration
+~~~~~~~~~~~~~~~~~~~~~
+
+Zuul will need access to a Jenkins user.  Create a user in Jenkins,
+and then visit the configuration page for the user:
+
+  https://jenkins.example.com/user/USERNAME/configure
+
+And click **Show API Token** to retrieve the API token for that user.
+You will need this later when configuring Zuul.  Make sure that this
+user has appropriate permission to build any jobs that you want Zuul
+to trigger.
+
+Make sure the notification plugin is installed.  Visit the plugin
+manager on your jenkins:
+
+  https://jenkins.example.com/pluginManager/
+
+And install **Jenkins Notification plugin**.  The homepage for the
+plugin is at:
+
+  https://wiki.jenkins-ci.org/display/JENKINS/Notification+Plugin
+
+Jenkins Job Configuration
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+For each job that you want Zuul to trigger, you will need to add a
+notification endpoint for the job on that job's configuration page.
+Click **Add Endpoint** and enter the following values:
+
+**Protocol**
+    ``HTTP``
+**URL**
+    ``http://127.0.0.1:8001/jenkins_endpoint``
+
+If you are running Zuul on a different server than Jenkins, enter the
+appropriate URL.  Note that Zuul itself has no access controls, so
+ensure that only Jenkins is permitted to access that URL.
+
+Zuul will pass some parameters to Jenkins for every job it launches.
+Check **This build is parameterized**, and add the following fields
+with the type **String Parameter**:
+
+**UUID**
+  Zuul provided key to link builds with Gerrit events
+**GERRIT_PROJECT**
+  Zuul provided project name
+**GERRIT_BRANCH**
+  Zuul provided branch name
+**GERRIT_CHANGES**
+  Zuul provided list of dependent changes to merge
+
+You may find it useful to use the ``GERRIT_*`` variables in your job.
+In particular, ``GERRIT_CHANGES`` indicates the change or changes that
+should be tested.  If Zuul has decided that more than one change
+should be merged and tested together, they will all be listed in
+``GERRIT_CHANGES``.  The format for the description of one change is::
+
+  project:branch:refspec
+
+And multiple changes are separated by a carat ("^").  E.g.::
+
+  testproject:master:refs/changes/20/420/1^testproject:master:refs/changes/21/421/1"
+
+The OpenStack project uses the following script to update the
+repository in a workspace and merge appropriate changes:
+
+  https://github.com/openstack/openstack-ci-puppet/blob/master/modules/jenkins_slave/files/slave_scripts/gerrit-git-prep.sh
+
+Gerrit events that do not include a change (e.g., ref-updated events
+which are emitted after a git ref is updated (i.e., a commit is merged
+to master)) require a slightly different set of parameters:
+
+**UUID**
+  Zuul provided key to link builds with Gerrit events
+**GERRIT_PROJECT**
+  Zuul provided project name
+**GERRIT_REFNAME**
+  Zuul provided ref name
+**GERRIT_OLDREV**
+  Zuul provided old reference for ref-updated
+**GERRIT_NEWREV**
+    Zuul provided new reference for ref-updated
+

doc/source/triggers.rst

@@ -0,0 +1,37 @@
+:title: Triggers
+
+Triggers
+========
+
+The process of merging a change starts with proposing a change to be
+merged.  Currently Zuul only supports Gerrit as a triggering system.
+Zuul's design is modular, so alternate triggering and reporting
+systems can be supported.  However, Gerrit has a particularly robust
+data model, and Zuul does make some assumptions that include that data
+model.  Nonetheless, patches to support alternate systems are welcome.
+
+Gerrit
+------
+
+Zuul works with standard versions of Gerrit by invoking the ``gerrit
+stream-events`` command over an SSH connection.  It also reports back
+to Gerrit using SSH.
+
+Gerrit Configuration
+~~~~~~~~~~~~~~~~~~~~
+
+Zuul will need access to a Gerrit user.  Consider naming the user
+*Jenkins* so that developers see that feedback from changes is from
+Jenkins (Zuul attempts to stay out of the way of developers, most
+shouldn't even need to know it's there).
+
+Create an SSH keypair for Zuul to use if there isn't one already, and
+create a Gerrit user with that key::
+
+  cat ~/id_rsa.pub | ssh -p29418 gerrit.example.com gerrit create-account --ssh-key - --full-name Jenkins jenkins
+
+Give that user whatever permissions will be needed on the projects you
+want Zuul to gate.  For instance, you may want to grant ``Verified
++/-1`` and ``Submit`` to the user.  Additional categories or values may
+be added to Gerrit.  Zuul is very flexible and can take advantage of
+those.

doc/source/zuul.rst

@@ -0,0 +1,319 @@
+:title: Zuul
+
+Zuul
+====
+
+Configuration
+-------------
+
+Zuul has three configuration files:
+
+**zuul.conf**
+  Credentials for Gerrit and Jenkins, locations of the other config files
+**layout.yaml**
+  Project and queue configuration -- what Zuul does
+**logging.conf**
+    Python logging config
+
+Examples of each of the three files can be found in the etc/ directory
+of the source distribution.
+
+zuul.conf
+~~~~~~~~~
+
+Zuul will look for ``/etc/zuul/zuul.conf`` or ``~/zuul.conf`` to
+bootstrap its configuration.  Alternately, you may specify ``-c
+/path/to/zuul.conf`` on the command line.
+
+Gerrit and Jenkins credentials are each described in a section of
+zuul.conf.  The location of the other two configuration files (as well
+as the location of the PID file when running Zuul as a server) are
+specified in a third section.
+
+layout.yaml
+~~~~~~~~~~~
+
+This is the main configuration file for Zuul, where all of the queues
+and projects are defined, what tests should be run, and what actions
+Zuul should perform.  There are three sections: queues, jobs, and
+projects.
+
+Queues
+""""""
+
+Zuul can have any number of independent queues.  Whenever a matching
+Gerrit event is found for a queue, that event is added to the queue,
+and the jobs specified for that queue are run.  When all jobs
+specified for the queue that were triggered by an event are completed,
+Zuul reports back to Gerrit the results.
+
+There are no pre-defined queues in Zuul, rather you can define
+whatever queues you need in the layout file.  This is a very flexible
+system that can accommodate many kinds of workflows.  
+
+Here is a quick example of a queue definition followed by an
+explanation of each of the parameters::
+
+  - name: check
+    manager: IndependentQueueManager
+    trigger:
+      - event: patchset-created
+    success:
+      verified: 1
+    failure:
+      verified: -1
+
+**name**
+  This is used later in the project definition to indicate what jobs
+  should be run for events in the queue.
+
+**manager**
+  There are currently two schemes for managing queues:
+
+  *IndependentQueueManager*
+    Every event in this queue should be treated as independent of
+    other events in the queue.  This is appropriate when the order of
+    events in the queue doesn't matter because the results of the
+    actions this queue performs can not affect other events in the
+    queue.  For example, when a change is first uploaded for review,
+    you may want to run tests on that change to provide early feedback
+    to reviewers.  At the end of the tests, the change is not going to
+    be merged, so it is safe to run these tests in parallel without
+    regard to any other changes in the queue.  They are independent.
+
+    Another type of queue that is independent is a post-merge queue.
+    In that case, the changes have already merged, so the results can
+    not affect any other events in the queue.
+
+  *DependentQueueManager*
+    The dependent queue manager is designed for gating.  It ensures
+    that every change is tested exactly as it is going to be merged
+    into the repository.  An ideal gating system would test one change
+    at a time, applied to the tip of the repository, and only if that
+    change passed tests would it be merged.  Then the next change in
+    line would be tested the same way.  In order to achieve parallel
+    testing of changes, the dependent queue manager performs
+    speculative execution on changes.  It orders changes based on
+    their entry into the queue.  It begins testing all changes in
+    parallel, assuming that each change ahead in the queue will pass
+    its tests.  If they all succeed, all the changes can be tested and
+    merged in parallel.  If a change near the front of the queue fails
+    its tests, each change behind it ignores whatever tests have been
+    completed and are tested again without the change in front.  This
+    way gate tests may run in parallel but still be tested correctly,
+    exactly as they will appear in the repository when merged.
+
+    One important characteristic of the DependentQueueManager is that
+    it analyzes the jobs that are triggered by different projects, and
+    if those projects have jobs in common, it treats those projects as
+    related, and they share a single virtual queue of changes.  Thus,
+    if there is a job that performs integration testing on two
+    projects, those two projects will automatically share a virtual
+    change queue.  If a third project does not invoke that job, it
+    will be part of a separate virtual change queue, and changes to it
+    will not depend on changes to the first two jobs.
+
+    For more detail on the theory and operation of Zuul's
+    DependentQueueManager, see: :doc:`gating`.
+
+**trigger**
+  This describes what Gerrit events should be placed in the queue.
+  Triggers are not exclusive -- matching events may be placed in
+  multiple queues, and they will behave independently in each of the
+  queues they match.  Multiple triggers may be listed.  Further
+  parameters describe the kind of events that match:
+
+  *event*
+  The event name from gerrit.  Examples: ``patchset-created``,
+  ``comment-added``, ``ref-updated``.  This field is treated as a
+  regular expression.
+
+  *branch*
+  The branch associated with the event.  Example: ``master``.  This
+  field is treated as a regular expression, and multiple branches may
+  be listed.
+
+  *ref*
+  On ref-updated events, the branch parameter is not used, instead the
+  ref is provided.  Currently Gerrit has the somewhat idiosyncratic
+  behavior of specifying bare refs for branch names (e.g., ``master``),
+  but full ref names for other kinds of refs (e.g., ``refs/tags/foo``).
+  Zuul matches what you put here exactly against what Gerrit
+  provides.  This field is treated as a regular expression, and
+  multiple refs may be listed.
+
+  *approval*
+  This is only used for ``comment-added`` events.  It only matches if
+  the event has a matching approval associated with it.  Example:
+  ``code-review: 2`` matches a ``+2`` vote on the code review category.
+  Multiple approvals may be listed.
+
+**success**
+  Describes what Zuul should do if all the jobs complete successfully.
+  This section is optional; if it is omitted, Zuul will run jobs and
+  do nothing on success; it will not even report a message to Gerrit.
+  If the section is present, it will leave a message on the Gerrit
+  review.  Each additional argument is assumed to be an argument to
+  ``gerrit review``, with the boolean value of ``true`` simply
+  indicating that the argument should be present without following it
+  with a value.  For example, ``verified: 1`` becomes ``gerrit
+  review --verified 1`` and ``submit: true`` becomes ``gerrit review
+  --submit``.
+
+**failure** 
+  Uses the same syntax as **success**, but describes what Zuul should
+  do if at least one job fails.
+  
+Some example queue configurations are included in the sample layout
+file.  The first is called a *check* queue::
+
+  - name: check
+    manager: IndependentQueueManager
+    trigger:
+      - event: patchset-created
+    success:
+      verified: 1
+    failure:
+      verified: -1
+
+This will trigger jobs each time a new patchset (or change) is
+uploaded to Gerrit, and report +/-1 values to Gerrit in the
+``verified`` review category. ::
+
+  - name: gate
+    manager: DependentQueueManager
+    trigger:
+      - event: comment-added
+        approval:
+          - approved: 1
+    success:
+      verified: 2
+      submit: true
+    failure:
+      verified: -2
+
+This will trigger jobs whenever a reviewer leaves a vote of ``1`` in the
+``approved`` review category in Gerrit (a non-standard category).
+Changes will be tested in such a way as to guarantee that they will be
+merged exactly as tested, though that will happen in parallel by
+creating a virtual queue of dependent changes and performing
+speculative execution of jobs. ::
+
+  - name: post
+    manager: IndependentQueueManager
+    trigger:
+      - event: ref-updated
+        ref: ^(?!refs/).*$
+
+This will trigger jobs whenever a change is merged to a named branch
+(e.g., ``master``).  No output will be reported to Gerrit.  This is
+useful for side effects such as creating per-commit tarballs. ::
+
+  - name: silent
+    manager: IndependentQueueManager
+    trigger:
+      - event: patchset-created
+
+This also triggers jobs when changes are uploaded to Gerrit, but no
+results are reported to Gerrit.  This is useful for jobs that are in
+development and not yet ready to be presented to developers.
+
+Jobs
+""""
+
+The jobs section is optional, and can be used to set attributes of
+jobs that are independent of their association with a project.  For
+example, if a job should return a customized message on failure, that
+may be specified here.  Otherwise, Zuul does not need to be told about
+each job as it builds a list from the project specification.
+
+**name**
+  The name of the job.  This field is treated as a regular expression
+  and will be applied to each job that matches.
+
+**failure-message**
+  The message that should be reported to Gerrit if the job fails
+  (optional).
+
+**success-message**
+  The message that should be reported to Gerrit if the job fails
+  (optional).
+
+**branch**
+  This job should only be run on matching branches.  This field is
+  treated as a regular expression and multiple branches may be
+  listed.
+
+Here is an example of setting the failure message for jobs that check
+whether a change merges cleanly::
+
+  - name: ^.*-merge$
+    failure-message: This change was unable to be automatically merged
+    with the current state of the repository. Please rebase your
+    change and upload a new patchset.
+
+Projects
+""""""""
+
+The projects section indicates what jobs should be run in each queue
+for events associated with each project.  It contains a list of
+projects.  Here is an example::
+
+  - name: example/project
+    check:
+      - project-merge:
+        - project-unittest
+	- project-pep8
+	- project-pyflakes
+    gate:
+      - project-merge:
+        - project-unittest
+	- project-pep8
+	- project-pyflakes
+    post:
+      - project-publish
+
+**name**
+  The name of the project (as known by Gerrit).
+
+This is followed by a section for each of the queues defined above.
+Queues may be omitted if no jobs should run for this project in a
+given queue.  Within the queue section, the jobs that should be
+executed are listed.  If a job is entered as a dictionary key, then
+jobs contained within that key are only executed if the key job
+succeeds.  In the above example, project-unittest, project-pep8, and
+project-pyflakes are only executed if project-merge succeeds.  This
+can help avoid running unnecessary jobs.
+
+.. seealso:: The OpenStack Zuul configuration for a comprehensive example: https://github.com/openstack/openstack-ci-puppet/blob/master/modules/openstack-ci-config/files/zuul/layout.yaml
+
+
+logging.conf
+~~~~~~~~~~~~
+This file is optional.  If provided, it should be a standard
+:mod:`logging.config` module configuration file.  If not present, Zuul will
+output all log messages of DEBUG level or higher to the console.
+
+Starting Zuul
+-------------
+
+To start Zuul, run **zuul-server**::
+
+  usage: zuul-server [-h] [-c CONFIG] [-d]
+
+  Project gating system.
+
+  optional arguments:
+    -h, --help  show this help message and exit
+    -c CONFIG   specify the config file
+    -d          do not run as a daemon
+
+You may want to use the ``-d`` argument while you are initially setting
+up Zuul so you can detect any configuration errors quickly.  Under
+normal operation, omit ``-d`` and let Zuul run as a daemon.
+
+If you send signal 1 (SIGHUP) to the zuul-server process, Zuul will
+stop executing new jobs, wait until all executing jobs are finished,
+reload its configuration, and resume.  Any values in any of the
+configuration files may be changed, except the location of Zuul's PID
+file (a change to that will be ignored until Zuul is restarted).

etc/layout.yaml-sample

@@ -2,7 +2,7 @@ queues:
   - name: check
     manager: IndependentQueueManager
     trigger:
-      - event: patchset-uploaded
+      - event: patchset-created
     success:
       verified: 1
     failure:

setup.cfg

@@ -0,0 +1,4 @@
+[build_sphinx]
+source-dir = doc/source
+build-dir = doc/build
+all_files = 1

tox.ini

@@ -1,10 +1,19 @@
 [tox]
 envlist = pep8, pyflakes
 
+[tox:jenkins]
+downloadcache = ~/cache/pip
+
 [testenv:pep8]
 deps = pep8
-commands = pep8 --repeat --show-source zuul zuul-server setup.py
+commands = pep8 --repeat --show-source --exclude=.venv,.tox,dist,doc .
+
+[testenv:cover]
+setenv = NOSE_WITH_COVERAGE=1
 
 [testenv:pyflakes]
 deps = pyflakes
 commands = pyflakes zuul zuul-server setup.py
+
+[testenv:venv]
+commands = {posargs}