sphinx: initial sphinx support

This commit is autogenerated pandoc to generate an inital set
of reST files based on DocBook XML files.

A .rst file is generated for each .xml files in all manuals with this
command:

cd <manual>
for i in *.xml; do \
  pandoc -f docbook -t rst --shift-heading-level-by=-1 \
  $i -o $(basename $i .xml).rst \
done

The conversion was done with: pandoc 2.9.2.1-91 (Arch Linux).

Also created an initial top level index file for each document, and
added all 'books' to the top leve index.rst file.

The YP manuals layout is organized as:

Book
  Chapter
    Section
      Section
        Section

Sphinx uses section headers to create the document structure.
ReStructuredText defines sections headers like that:

   To break longer text up into sections, you use section headers. These
   are a single line of text (one or more words) with adornment: an
   underline alone, or an underline and an overline together, in dashes
   "-----", equals "======", tildes "~~~~~~" or any of the
   non-alphanumeric characters = - ` : ' " ~ ^ _ * + # < > that you feel
   comfortable with. An underline-only adornment is distinct from an
   overline-and-underline adornment using the same character. The
   underline/overline must be at least as long as the title text. Be
   consistent, since all sections marked with the same adornment style
   are deemed to be at the same level:

Let's define the following convention when converting from Docbook:

Book                => overline ===   (Title)
  Chapter           => overline ***   (1.)
    Section         => ====           (1.1)
      Section       => ----           (1.1.1)
        Section     => ~~~~           (1.1.1.1)
          Section   => ^^^^           (1.1.1.1.1)

During the conversion with pandoc, we used --shift-heading-level=-1 to
convert most of DocBook headings automatically. However with this
setting, the Chapter header was removed, so I added it back
manually. Without this setting all headings were off by one, which was
more difficult to manually fix.

At least with this change, we now have the same TOC with Sphinx and
DocBook.

(From yocto-docs rev: 3c73d64a476d4423ee4c6808c685fa94d88d7df8)

Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 287 insertions, 0 deletions

diff --git a/documentation/test-manual/test-manual-understand-autobuilder.rst b/documentation/test-manual/test-manual-understand-autobuilder.rst
new file mode 100644
index 0000000000..69700088aa
--- /dev/null
+++ b/documentation/test-manual/test-manual-understand-autobuilder.rst
@@ -0,0 +1,287 @@
+*******************************************
+Understanding the Yocto Project Autobuilder
+*******************************************
+
+Execution Flow within the Autobuilder
+=====================================
+
+The “a-full” and “a-quick” targets are the usual entry points into the
+Autobuilder and it makes sense to follow the process through the system
+starting there. This is best visualised from the Autobuilder Console
+view (`https://autobuilder.yoctoproject.org/typhoon/#/console <#>`__).
+
+Each item along the top of that view represents some “target build” and
+these targets are all run in parallel. The ‘full’ build will trigger the
+majority of them, the “quick” build will trigger some subset of them.
+The Autobuilder effectively runs whichever configuration is defined for
+each of those targets on a seperate buildbot worker. To understand the
+configuration, you need to look at the entry on ``config.json`` file
+within the ``yocto-autobuilder-helper`` repository. The targets are
+defined in the ‘overrides’ section, a quick example could be qemux86-64
+which looks like:"qemux86-64" : { "MACHINE" : "qemux86-64", "TEMPLATE" :
+"arch-qemu", "step1" : { "extravars" : [ "IMAGE_FSTYPES_append = ' wic
+wic.bmap'" ] } },And to expand that, you need the “arch-qemu” entry from
+the “templates” section, which looks like:"arch-qemu" : { "BUILDINFO" :
+true, "BUILDHISTORY" : true, "step1" : { "BBTARGETS" : "core-image-sato
+core-image-sato-dev core-image-sato-sdk core-image-minimal
+core-image-minimal-dev core-image-sato:do_populate_sdk", "SANITYTARGETS"
+: "core-image-minimal:do_testimage core-image-sato:do_testimage
+core-image-sato-sdk:do_testimage core-image-sato:do_testsdk" }, "step2"
+: { "SDKMACHINE" : "x86_64", "BBTARGETS" :
+"core-image-sato:do_populate_sdk core-image-minimal:do_populate_sdk_ext
+core-image-sato:do_populate_sdk_ext", "SANITYTARGETS" :
+"core-image-sato:do_testsdk core-image-minimal:do_testsdkext
+core-image-sato:do_testsdkext" }, "step3" : { "BUILDHISTORY" : false,
+"EXTRACMDS" : ["${SCRIPTSDIR}/checkvnc; DISPLAY=:1 oe-selftest
+${HELPERSTMACHTARGS} -j 15"], "ADDLAYER" :
+["${BUILDDIR}/../meta-selftest"] } },Combining these two entries you can
+see that “qemux86-64” is a three step build where the
+``bitbake BBTARGETS`` would be run, then ``bitbake
+                SANITYTARGETS`` for each step; all for
+``MACHINE=”qemx86-64”`` but with differing SDKMACHINE settings. In step
+1 an extra variable is added to the ``auto.conf`` file to enable wic
+image generation.
+
+While not every detail of this is covered here, you can see how the
+templating mechanism allows quite complex configurations to be built up
+yet allows duplication and repetition to be kept to a minimum.
+
+The different build targets are designed to allow for parallelisation,
+so different machines are usually built in parallel, operations using
+the same machine and metadata are built sequentially, with the aim of
+trying to optimise build efficiency as much as possible.
+
+The ``config.json`` file is processed by the scripts in the Helper
+repository in the ``scripts`` directory. The following section details
+how this works.
+
+.. _test-autobuilder-target-exec-overview:
+
+Autobuilder Target Execution Overview
+=====================================
+
+For each given target in a build, the Autobuilder executes several
+steps. These are configured in ``yocto-autobuilder2/builders.py`` and
+roughly consist of:
+
+1. *Run ``clobberdir``*
+
+   This cleans out any previous build. Old builds are left around to
+   allow easier debugging of failed builds. For additional information,
+   see ```clobberdir`` <#test-clobberdir>`__.
+
+2. *Obtain yocto-autobuilder-helper*
+
+   This step clones the ``yocto-autobuilder-helper`` git repository.
+   This is necessary to prevent the requirement to maintain all the
+   release or project-specific code within Buildbot. The branch chosen
+   matches the release being built so we can support older releases and
+   still make changes in newer ones.
+
+3. *Write layerinfo.json*
+
+   This transfers data in the Buildbot UI when the build was configured
+   to the Helper.
+
+4. *Call scripts/shared-repo-unpack*
+
+   This is a call into the Helper scripts to set up a checkout of all
+   the pieces this build might need. It might clone the BitBake
+   repository and the OpenEmbedded-Core repository. It may clone the
+   Poky repository, as well as additional layers. It will use the data
+   from the ``layerinfo.json`` file to help understand the
+   configuration. It will also use a local cache of repositories to
+   speed up the clone checkouts. For additional information, see
+   `Autobuilder Clone Cache <#test-autobuilder-clone-cache>`__.
+
+   This step has two possible modes of operation. If the build is part
+   of a parent build, its possible that all the repositories needed may
+   already be available, ready in a pre-prepared directory. An "a-quick"
+   or "a-full" build would prepare this before starting the other
+   sub-target builds. This is done for two reasons:
+
+   -  the upstream may change during a build, for example, from a forced
+      push and this ensures we have matching content for the whole build
+
+   -  if 15 Workers all tried to pull the same data from the same repos,
+      we can hit resource limits on upstream servers as they can think
+      they are under some kind of network attack
+
+   This pre-prepared directory is shared among the Workers over NFS. If
+   the build is an individual build and there is no "shared" directory
+   available, it would clone from the cache and the upstreams as
+   necessary. This is considered the fallback mode.
+
+5. *Call scripts/run-config*
+
+   This is another call into the Helper scripts where its expected that
+   the main functionality of this target will be executed.
+
+.. _test-autobuilder-tech:
+
+Autobuilder Technology
+======================
+
+The Autobuilder has Yocto Project-specific functionality to allow builds
+to operate with increased efficiency and speed.
+
+.. _test-clobberdir:
+
+clobberdir
+----------
+
+When deleting files, the Autobuilder uses ``clobberdir``, which is a
+special script that moves files to a special location, rather than
+deleting them. Files in this location are deleted by an ``rm`` command,
+which is run under ``ionice -c 3``. For example, the deletion only
+happens when there is idle IO capacity on the Worker. The Autobuilder
+Worker Janitor runs this deletion. See `Autobuilder Worker
+Janitor <#test-autobuilder-worker-janitor>`__.
+
+.. _test-autobuilder-clone-cache:
+
+Autobuilder Clone Cache
+-----------------------
+
+Cloning repositories from scratch each time they are required was slow
+on the Autobuilder. We therefore have a stash of commonly used
+repositories pre-cloned on the Workers. Data is fetched from these
+during clones first, then "topped up" with later revisions from any
+upstream when necesary. The cache is maintained by the Autobuilder
+Worker Janitor. See `Autobuilder Worker
+Janitor <#test-autobuilder-worker-janitor>`__.
+
+.. _test-autobuilder-worker-janitor:
+
+Autobuilder Worker Janitor
+--------------------------
+
+This is a process running on each Worker that performs two basic
+operations, including background file deletion at IO idle (see `Target
+Execution: clobberdir <#test-list-tgt-exec-clobberdir>`__) and
+maintainenance of a cache of cloned repositories to improve the speed
+the system can checkout repositories.
+
+.. _test-shared-dl-dir:
+
+Shared DL_DIR
+-------------
+
+The Workers are all connected over NFS which allows DL_DIR to be shared
+between them. This reduces network accesses from the system and allows
+the build to be sped up. Usage of the directory within the build system
+is designed to be able to be shared over NFS.
+
+.. _test-shared-sstate-cache:
+
+Shared SSTATE_DIR
+-----------------
+
+The Workers are all connected over NFS which allows the ``sstate``
+directory to be shared between them. This means once a Worker has built
+an artefact, all the others can benefit from it. Usage of the directory
+within the directory is designed for sharing over NFS.
+
+.. _test-resulttool:
+
+Resulttool
+----------
+
+All of the different tests run as part of the build generate output into
+``testresults.json`` files. This allows us to determine which tests ran
+in a given build and their status. Additional information, such as
+failure logs or the time taken to run the tests, may also be included.
+
+Resulttool is part of OpenEmbedded-Core and is used to manipulate these
+json results files. It has the ability to merge files together, display
+reports of the test results and compare different result files.
+
+For details, see `https://wiki.yoctoproject.org/wiki/Resulttool <#>`__.
+
+.. _test-run-config-tgt-execution:
+
+run-config Target Execution
+===========================
+
+The ``scripts/run-config`` execution is where most of the work within
+the Autobuilder happens. It runs through a number of steps; the first
+are general setup steps that are run once and include:
+
+1. Set up any ``buildtools-tarball`` if configured.
+
+2. Call "buildhistory-init" if buildhistory is configured.
+
+For each step that is configured in ``config.json``, it will perform the
+following:
+
+## WRITER's question: What does "logging in as stepXa" and others refer
+to below? ##
+
+1. Add any layers that are specified using the
+   ``bitbake-layers add-layer`` command (logging as stepXa)
+
+2. Call the ``scripts/setup-config`` script to generate the necessary
+   ``auto.conf`` configuration file for the build
+
+3. Run the ``bitbake BBTARGETS`` command (logging as stepXb)
+
+4. Run the ``bitbake SANITYTARGETS`` command (logging as stepXc)
+
+5. Run the ``EXTRACMDS`` command, which are run within the BitBake build
+   environment (logging as stepXd)
+
+6. Run the ``EXTRAPLAINCMDS`` command(s), which are run outside the
+   BitBake build environment (logging as stepXd)
+
+7. Remove any layers added in `step
+   1 <#test-run-config-add-layers-step>`__ using the
+   ``bitbake-layers remove-layer`` command (logging as stepXa)
+
+Once the execution steps above complete, ``run-config`` executes a set
+of post-build steps, including:
+
+1. Call ``scripts/publish-artifacts`` to collect any output which is to
+   be saved from the build.
+
+2. Call ``scripts/collect-results`` to collect any test results to be
+   saved from the build.
+
+3. Call ``scripts/upload-error-reports`` to send any error reports
+   generated to the remote server.
+
+4. Cleanup the build directory using
+   ```clobberdir`` <#test-clobberdir>`__ if the build was successful,
+   else rename it to “build-renamed” for potential future debugging.
+
+.. _test-deploying-yp-autobuilder:
+
+Deploying Yocto Autobuilder
+===========================
+
+The most up to date information about how to setup and deploy your own
+Autbuilder can be found in README.md in the ``yocto-autobuilder2``
+repository.
+
+We hope that people can use the ``yocto-autobuilder2`` code directly but
+it is inevitable that users will end up needing to heavily customise the
+``yocto-autobuilder-helper`` repository, particularly the
+``config.json`` file as they will want to define their own test matrix.
+
+The Autobuilder supports wo customization options:
+
+-  variable substitution
+
+-  overlaying configuration files
+
+The standard ``config.json`` minimally attempts to allow substitution of
+the paths. The Helper script repository includes a
+``local-example.json`` file to show how you could override these from a
+separate configuration file. Pass the following into the environment of
+the Autobuilder:$ ABHELPER_JSON="config.json local-example.json"As
+another example, you could also pass the following into the
+environment:$ ABHELPER_JSON="config.json /some/location/local.json"One
+issue users often run into is validation of the ``config.json`` files. A
+tip for minimizing issues from invalid json files is to use a Git
+``pre-commit-hook.sh`` script to verify the JSON file before committing
+it. Create a symbolic link as follows:$ ln -s
+../../scripts/pre-commit-hook.sh .git/hooks/pre-commit