======
README
======


``p01.build`` is a command line tool for quickly creating new (egg) releases.


Sample
------

As an example, consider a web application called MyServer:

- ``p01.cdn`` - cdn resources like css and javascript files

- ``p01.core`` - a package providing your application model

- ``p01.web`` - a web front end for the ``p01.core`` package and using the
  p01.cdn resources

Using ``p01.build`` you will be able to manage the lifecycle of these
python packages and any number of deployment configurations coherently:

- Allow you to define a project, which is a collection of
  interdependent eggs that generally get released together.

- Automatically deploy new egg releases of each package when necessary.

- Upload new eggs to a private egg repository (see mpypi).

- Generate versioned buildout configuration files that combine the
  eggs properly.

- Upload the buildout configuration files to a private configuration server.
  (mypypi has built in support such uploads)

- Upload dependent buildout configuration files to a private configuration
  server (by checking the extends= chain, mypypi support such uploads)


Installation
------------

Install the ``deploy`` script with easy_install::

  $ easy_install p01.build

You can also install a developer version of p01.build

Checkout the code::

  $ svn checkout svn://svn.zope.org/repos/main/p01.build/trunk p01.build
  $ cd p01.build

Run the bootstrap script and buildout::

  $ python bootstrap.py
  $ ./bin/buildout


Release
-------

Once you have working developer version available, you should be able to run
the ``build-package`` script. (Found in *./bin/build-package* with developer
installations).

Usage::

  $ build-package [options]

Options:

-h, --help
    Show help message and exit.

-c FILE, --config-file=FILE
    The file containing the configuration of the project.

-q, --quiet
    When specified, no messages are displayed.

-v, --verbose
    When specified, debug information is created.

-d, --use-defaults
    When specified, no user input is required and the defaults are used.

-o, --offline-mode
    When set, no server commands are executed.

-n, --next-version
    When set, the system guesses the next version to generate.

-b BRANCH, --use-branch=BRANCH
    When specified, this branch will be always used.

-i, --independent-branches
    When specified, the system guesses the next version from all branches.
    This is important if you release from different branches. It will
    prevent that a package gets used which was released from another branch.

--no-upload
    When set, the generated configuration files are not uploaded.

--no-branch-update
    When set, the branch is not updated with a new version after a release
    is created.

-s PATH, --storage-path=PATH
    Store the generated files in that folder and not in the global root
    directory. This provides a clean setup and prevents putting all the
    generated config files in the package root


Getting Started
---------------

Assumptions; First we need to start with some assumptions that p01.build has
about the way packages are laid out. When developing multiple packages in
tandem, it often makes sense to have your subversion repository laid
out like so::

  SVNROOT/MyServer/packages/
      branches/
          Branch-0.x/
              ...
          Branch-1.x/
              p01.cdn/
              p01.core/
              p01.web/
      tags/
          p01.cdn-0.5.0/
          p01.core-0.5.0/
          p01.core-0.5.1/
          p01.web-0.5.0/
          p01.web-0.5.1/
          p01.web-0.5.2/
          ...
      trunk/
          p01.cdn/
          p01.core/
          p01.web/

The important thing to note is that each package does *not* have its
own branches/ tags/ trunk/ directories, but rather there is just one
set of the entire "project."


Project setup
-------------

Before you can really do anything with the ``build-package`` script,
you have to define a configuration file. Project configuration files
use the INI [#ini]_ file format.  Every project configuration file
must have a ``[build]`` section.  The project configuration file for
the MyServer would look something like this::


  # MyServer.cfg

  [build]
  name = MyServer  # this has nothing to do with the package namespace
  version = +
  template = release.cfg
  tag-layout = subfolder
  upload-type = setup.py
  package-index = https://pypi.projekt01.ch/private
  package-index-username = username
  package-index-password = password
  buildout-server = https://pypi.projekt01.ch/++projects++/
  buildout-server-username = username
  buildout-server-password = password
  svn-repos = https://svn.projekt01.ch/svn/myserver/packages/
  svn-repos-username = somesvnuser
  svn-repos-password = somepass
  svn-trust-server-cert = 1
  packages = p01.cdn
             p01.core
             p01.web

Let's go over each of the settings in the ``build`` section of
*MyServer.cfg*.

- **name** - This is the name of the project. It can be anything you
  want and has nothing to do with the packages that make up the
  project.  The name will be part of the generation buildout
  configuration files.

- **version** - This is the version to use when making a new release
  of the Project.  The version number becomes part of the filename for
  the generated buildout configuration files.

  - Using **+** as the version will simply increment the version
    number of the project from the versions that have already been
    released.

- **template** - This is a base buildout configuration file to use for
  all deployments.  When a new Project release is created, the
  ``[versions]`` section will automatically be updated with the
  correct versions of each of the ``p01.*`` packages.  More on
  this later.

- **tag-layout** - Choose from ``flat`` or ``subfolder``

  - **flat** Tags will be created in svn as /tags/package-version
    This is the default setting.

  - **subfolder** Tags will be created in svn as /tags/package/version

- **upload-type** - Choose from ``internal`` or ``setup.py``

  - **internal** Upload packages to a WebDAV enabled web server using the
    below credetials. This is the default setting.
    (actually does a ``python setup.py sdist`` and uploads the result)

  - **setup.py** Executes ``python setup.py sdist register upload``,
    does nothing else as this command should take care of the upload.

- **upload-format** - setup.py release format option use as --formats argument.
  Choose from ``zip``, ``gztar``, ``bztar``, ``ztar`` or ``tar``. Note, there
  is only one format option allowed.

- **package-index** - The url to a WebDAV [#webdav]_ enabled web
  server where generated eggs for each of the ``p01.*`` packages
  should be uploaded. Used for upload only if ``upload-type`` is ``internal``.
  Also used to check/get existing versions of packages.

- **package-index-username** - The username for accessing the WebDAV
  server

- **package-index-password** - The password for accessing the WebDAV
  server

- **buildout-upload-type** - Choose from ``webdav``, ``local`` or ``mypypi``

  - **webdav** Upload generated buildout files to the url specified by
    ``buildout-server`` with the WebDAV protocol.

  - **local** Just generate buildout files, don't upload them.
    If ``buildout-server`` is given buildout files will be copied to that
    folder.

  - **mypypi** Upload generated buildout files to the url specified by
    ``buildout-server``. The url should point to the mypypi upload page.
    (Something like http://yourhost/++projects++/)

- **buildout-server** - The url to a WebDAV enabled web
  server where generated buildout files should be uploaded.
  If ``buildout-upload-type`` is ``local`` this is a path on the local
  filesystem. Buildout files wil be copied to this folder.
  If not given, the process stops after releasing the packages.

- **buildout-server-username** - The username for accessing the WebDAV
  server

- **buildout-server-password** - The password for accessing the WebDAV
  server

- **svn-repos** - The url for the subversion repository where all the
  source code lives, including release tags.

- **svn-repos-username** - The username for the url repository.
  Use the command line option ``--force-svnauth`` to force all svn operations
  to use this credential.
  Otherwise cached authentication will be used.

- **svn-repos-password** - The password for the url repository.

- **svn-trust-server-cert** - Trust svn server certificate.

- **hash-config-files** - Add hashes based on file content to dependent config
  filenames.

- **packages** - a list of packages that are part of the project.
  These are the packages that live in the svn repository and that
  should be released in conjunction with each other.


Defining a Release Template
---------------------------

As we saw in the previous section, *MyServer.cfg* refers to a file
called *release.cfg*.  This is just a base buildout configuration. Additional
to this, we can also define different configuration data as define in stage and
production section. Such sections can get used in a product deployment as
additional (shared) variables.  For the MyServer project, it might look like
this::

  # release.cfg

  [buildout]
  extends = http://download.zope.org/zope3.4/3.4.0/versions.cfg
  parts = test
  find-links = https://pypi.projekt01.ch/private

  [test]
  recipe = zc.recipe.testrunner
  eggs = p01.cdn
         p01.core
         p01.web

  [app]
  recipe = zc.zope3recipes:app
  servers = zserver
  site.zcml = <include package="p01.web" file="app.zcml" />
  eggs = p01.web

  [zope3]
  location =

  [stage]
  memcached = 127.0.0.1:11211

  [production]
  memcached = 10.0.0.1:11211


When a new release of the MyServer project is made, a ``[versions]``
section will be added to this configuration file with all the
correct ``p01.*`` versions pinned down.


Defining Multiple Deployment Configurations
-------------------------------------------

Each time you release a Project, you may want to generate different
buildout configuration files for all the different deployment
environments you might have.  For example, you may have three
different environments: Development, Stage, and Production. These are
called variants.  Each environment may need to have the application
run on different ports, at different log levels, or have other small
differences.

We can easily generate additional configuration variants by adding
addtional sections to the *MyServer.cfg* file::

  # MyServer.cfg

  [Development]
  template = instance.cfg
  vars = stage
  port = 9080
  logdir = /opt/myserver/dev/logs
  install-dir = /opt/myserver/dev
  loglevel = debug
  cache-size = 1000

  [Stage]
  template = instance.cfg
  vars = stage
  port = 9082
  logdir = /opt/myserver/stage/logs
  install-dir = /opt/myserver/stage
  loglevel = info
  cache-size = 1000

  [Production]
  template = instance.cfg
  vars = production
  port = 8080
  logdir = /var/log/myserver
  install-dir = /opt/myserver/
  loglevel = warn
  cache-size = 200000

We can then have a single *instance.cfg* file that uses python's built in
string templating to access the variables we set in *MyServer.cfg*.  For the
MyServer project, it might look like this::

  # instance.cfg

  [buildout]
  parts += server
  directory = %(install-dir)s

  [database]
  recipe = zc.recipe.filestorage

  [server]
  recipe = zc.zope3recipes:instance
  application = server-app
  zope.conf =

    <product-config memcached>
      memcached %(memcached)s
    </product-config>

    <zodb>
      cache-size %(cache-size)s
      <filestorage>
        path ${database:path}
      </filestorage>
    </zodb>

    <server>
      type WSGI-HTTP
      address %(port)s
    </server>

    <eventlog>
      level %(loglevel)s
      <logfile>
        formatter zope.exceptions.log.Formatter
        path %(logdir)s/server.log
      </logfile>
    </eventlog>

    <accesslog>
      <logfile>
        level info
        path %(logdir)s/server-access.log
      </logfile>
    </accesslog>

As you can see, the MyServer.cfg uses additional vars (stage, production) which
makes it very simple to define a lagrge amount of shared attributes in a
release template and use them in the instance template. Note, a side effect
from the python config parser is, that you will inherit arguments define in a
duplicated section define in an template loaded via (buildout) extends.


Releasing a Project
-------------------

Once you have created all the necessary configuration files, you can
make your first project release.  This is where the ``build-package``
script comes in to play.  The first time you run the ``build-package``
script, the only option you need to pass in will be the configuration
file.

The ``build-package`` script will prompt you for version information
about each of the packages it will be releasing as part of the
MyServer.cfg project.  Your first interaction with the script might look
like this::

  $ build-package -c MyServer.cfg --quiet
  Version for `p01.cdn` : 1.0.0
  The release p01.cdn-1.0.0 does not exist.
  Do you want to create it? yes/no [yes]: yes
  Version for `p01.core` : 1.0.0
  The release p01.core-1.0.0 does not exist.
  Do you want to create it? yes/no [yes]: yes
  Version for `p01.web` : 1.0.0
  The release p01.web-1.0.0 does not exist.
  Do you want to create it? yes/no [yes]: yes

The next time you make a release, you can set the ``-n`` flag for
``build-package`` to automatically guess the next version that should
be released.  It does this by first looking for all the release tags
of a given package and finding the last changed revision for the trunk
of a given package.  If any code for the given package was changed
since the last time it was released, it will bump the most minor
version number automatically.  If no change has occured, it will
choose the latest existing release.

You can also use the ``-d`` flag to make ``build-package`` not prompt
you before creating a new release.

If you need to make a new release from a particular branch, you can
use the ``-b`` option.  For example, if bug fixes have been made to the
MyServer-1.x branch, we can create a new release using code from this
branch like this::

  $ build-package -c MyServer.cfg -nb MyServer-1.x

When the new package versions are calculated, they will be versioned
along the 1.x line, even if you have since created 2.x releases, by
analyzing the name of the branch.

Caveat when using ``-n`` and ``-d`` on a branch with a branchname ending
with the version number is that you'll need to have the package versions
matching the branch version.
E.g. having a branch: ``branches/myserver-1.9`` will suppose packages like
``p01.core-1.9.x`` and ``p01.web-1.9.x`` and so on.
You should be aware of this also when releasing packages from the trunk.
Most probably you'll drive development on the trunk and branch out for a
stable. In this case package versions on the branch should be kept inline.


Install a Released Project
---------------------------

``p01.build`` also comes with a very simple installation script that
can be used to quickly install any variant of the released project::

  $ deploy --help
  Usage: deploy [options]

  Options:
    -h, --help            show this help message and exit
    -u URL, --url=URL     The base URL at which the releases can be found.
    -p PROJECT, --project=PROJECT
                          The name of the project to be installed.
    -V VARIANT, --variant=VARIANT
                          The variant of the project to be installed.
    -v VERSION, --version=VERSION
                          The version of the project to be installed.
    --directory=FOLDER    Override installation target folder
    -l, --latest          When specified, the latest version will be chosen.
    --username=USER       The username needed to access the site.
    --password=PASSWORD   The password needed to access the site.
    -b PATH, --buildout-path=PATH
                          The path to the buildout executable.
    --quiet               When specified, no messages are displayed.
    --verbose             When specified, debug information is created.
    --timeout=TIMEOUT     Socket timeout passed on to buildout.

For example, to install the latest Stage version of the ``MyServer`` project,
you would run:

  $ deploy -u https://pypi.projekt01.ch/++projects++/ -p MyServer -V Stage --latest


Creating Helper Scripts
-----------------------

Sometimes it can be a pain to remember what all the command line
options are that you need to pass for building your project.
Fortunately, it is really easy to create helper scripts that just set
some defaults for you.

For example, to create a build-myserver script, you would add the
following to a buildout configuration file::

  [uploads]
  recipe = p01.recipe.setup:mkdir
  path = ${buildout:directory}/parts/uploads

  [build-myserver]
  recipe = zc.recipe.egg
  eggs = p01.build
  scripts = build=build-myserver
  initialization =
      sys.argv[1:1] = ['-c', 'MyServer.cfg',
                       '-o', '${buildout:directory}/parts/uploads']

The possibilities are endless!

Footnotes
=========

.. [#ini] See http://en.wikipedia.org/wiki/INI_file
.. [#webdav] See http://en.wikipedia.org/wiki/WebDAV
