.. _first-run-label:

=========
First Run
=========

Goal
----

This tutorial will take you from zero to running your first buildbot master and worker as quickly
as possible, without changing the default configuration.

This tutorial is all about instant gratification and the five minute experience: in five minutes we
want to convince you that this project works, and that you should seriously consider spending time
learning the system. In this tutorial no configuration or code changes are done.

This tutorial assumes that you are running Unix, but might be adaptable to Windows.

Thanks to virtualenv_, installing buildbot in a standalone environment is very easy. For those more
familiar with Docker_, there also exists a :ref:`docker version of these instructions
<first-run-docker-label>`.

You should be able to cut and paste each shell block from this tutorial directly into a terminal.

Simple introduction to BuildBot
-------------------------------

Before trying to run BuildBot it's helpful to know what BuildBot is.

BuildBot is a continuous integration framework written in Python. It consists of a master daemon
and potentially many worker daemons that usually run on other machines. The master daemon runs a
web server that allows the end user to start new builds and to control the behaviour of the
BuildBot instance. The master also distributes builds to the workers. The worker daemons connect to
the master daemon and execute builds whenever master tells them to do so.

In this tutorial we will run a single master and a single worker on the same machine.

A more thorough explanation can be found in the :ref:`manual section <Introduction>` of the Buildbot documentation.

.. _Docker: https://docker.com

.. _getting-code-label:

Getting ready
-------------

There are many ways to get the code on your machine.
We will use the easiest one: via ``pip`` in a virtualenv_.
It has the advantage of not polluting your operating system, as everything will be contained in the virtualenv.

To make this work, you will need the following installed:

* Python_ and the development packages for it
* virtualenv_

.. _Python: https://www.python.org/
.. _virtualenv: https://pypi.python.org/pypi/virtualenv

Preferably, use your distribution package manager to install these.

You will also need a working Internet connection, as virtualenv and pip will need to download other
projects from the Internet. The master and builder daemons will need to be able to connect to
``github.com`` via HTTPS to fetch the repo we're testing.

If you need to use a proxy for this ensure that either the ``HTTPS_PROXY`` or ``ALL_PROXY``
environment variable is set to your proxy, e.g., by executing ``export
HTTPS_PROXY=http://localhost:9080`` in the shell before starting each daemon.

.. note::

    Buildbot does not require root access.
    Run the commands in this tutorial as a normal, unprivileged user.

Creating a master
-----------------

The first necessary step is to create a virtualenv for our master.
We first create a separate directory to demonstrate the distinction between a master and worker:

.. code-block:: bash

  mkdir -p ~/buildbot-test/master_root
  cd ~/buildbot-test/master_root

Then we create the virtual environment. On Python 3:

.. code-block:: bash

  python3 -m venv sandbox
  source sandbox/bin/activate


Next, we need to install several build dependencies to make sure we can install buildbot and its supporting packages.
These build dependencies are:

* GCC build tools (``gcc`` for RHEL/CentOS/Fedora based distributions, or ``build-essential``
  for Ubuntu/Debian based distributions).
* Python development library (``python3-devel`` for RHEL/CentOS/Fedora based distributions, or
  ``python3-dev`` for Ubuntu/Debian based distributions).
* OpenSSL development library (``openssl-devel`` for RHEL/CentOS/Fedora based distributions, or
  ``libssl-dev`` for Ubuntu/Debian based distributions).
* `libffi` development library (``libffi-devel`` for RHEL/CentOS/Fedora based distributions, or
  ``libffi-dev`` for Ubuntu/Debian based distributions).

Install these build dependencies:

.. code-block:: bash

  # if in Ubuntu/Debian based distributions:
  sudo apt-get install build-essential python3-dev libssl-dev libffi-dev

  # if in RHEL/CentOS/Fedora based distributions:
  sudo yum install gcc python3-devel openssl-devel libffi-devel


or refer to your distribution's documentation on how to install these packages.


Now that we are ready, we need to install buildbot:

.. code-block:: bash

  pip install --upgrade pip
  pip install 'buildbot[bundle]'

Now that buildbot is installed, it's time to create the master.
``my_master`` represents a path to a directory, where future master will be created:

.. code-block:: bash

  buildbot create-master my_master

Buildbot's activity is controlled by a configuration file. Buildbot by default uses configuration
from file at ``master.cfg``, but its installation comes with a sample configuration file named
``master.cfg.sample``. We will use the sample configuration file unchanged, but we have to rename
it to ``master.cfg``:

.. code-block:: bash

  mv my_master/master.cfg.sample my_master/master.cfg

Finally, start the master:

.. code-block:: bash

  buildbot start my_master

You will now see some log information from the master in this terminal.
It should end with lines like these:

.. code-block:: none

    2014-11-01 15:52:55+0100 [-] BuildMaster is running
    The buildmaster appears to have (re)started correctly.

From now on, feel free to visit the web status page running on the port 8010: http://localhost:8010/

Our master now needs (at least) one worker to execute its commands.
For that, head on to the next section!

Creating a worker
-----------------

The worker will be executing the commands sent by the master.
In this tutorial, we are using the buildbot/hello-world project as an example.
As a consequence of this, your worker will need access to the git_ command in order to checkout some code.
Be sure that it is installed, or the builds will fail.

Same as we did for our master, we will create a virtualenv for our worker next to the master's one.
It would however be completely ok to do this on another computer - as long as the *worker* computer
is able to connect to the *master's* . We first create a new directory for the worker:

.. code-block:: bash

  mkdir -p ~/buildbot-test/worker_root
  cd ~/buildbot-test/worker_root

Again, we create a virtual environment. On Python 3:

.. code-block:: bash

  python3 -m venv sandbox
  source sandbox/bin/activate

Install the ``buildbot-worker`` command:

.. code-block:: bash

   pip install --upgrade pip
   pip install buildbot-worker
   # required for `runtests` build
   pip install setuptools-trial

Now, create the worker:

.. code-block:: bash

  buildbot-worker create-worker my_worker localhost example-worker pass

.. note::

    If you decided to create this from another computer, you should replace ``localhost`` with the
    name of the computer where your master is running.

The username (``example-worker``), and password (``pass``) should be the same as those in
:file:`my_master/master.cfg`; verify this is the case by looking at the section for
``c['workers']``:

.. code-block:: bash

  cat ../master_root/my_master/master.cfg

And finally, start the worker:

.. code-block:: bash

  buildbot-worker start my_worker

Check the worker's output.
It should end with lines like these:

.. code-block:: none

  2014-11-01 15:56:51+0100 [-] Connecting to localhost:9989
  2014-11-01 15:56:51+0100 [Broker,client] message from master: attached
  The worker appears to have (re)started correctly.

Meanwhile, from the other terminal, in the master log (:file:`twisted.log` in the master
directory), you should see lines like these:

.. code-block:: none

  2014-11-01 15:56:51+0100 [Broker,1,127.0.0.1] worker 'example-worker' attaching from
  IPv4Address(TCP, '127.0.0.1', 54015)
  2014-11-01 15:56:51+0100 [Broker,1,127.0.0.1] Got workerinfo from 'example-worker'
  2014-11-01 15:56:51+0100 [-] bot attached

Wrapping up
-----------

Your directory tree now should look like this:

.. code-block:: none

    ~/buildbot-test/master_root/my_master  # master base directory
    ~/buildbot-test/master_root/sandbox    # virtualenv for master

    ~/buildbot-test/worker_root/my_worker  # worker base directory
    ~/buildbot-test/worker_root/sandbox    # virtualenv for worker

You should now be able to go to http://localhost:8010, where you will see a web page similar to:

.. image:: _images/index.png
   :alt: index page

Click on "Builds" at the left to open the submenu and then
`Builders <http://localhost:8010/#/builders>`_ to see that the worker you just started (identified
by the green bubble) has connected to the master:

.. image:: _images/builders.png
   :alt: builder runtests is active.

Your master is now quietly waiting for new commits to hello-world.
This doesn't happen very often though.
In the next section, we'll see how to manually start a build.

We just wanted to get you to dip your toes in the water. It's easy to take your first steps, but
this is about as far as we can go without touching the configuration.

You've got a taste now, but you're probably curious for more.
Let's step it up a little in the second tutorial by changing the configuration and doing an actual build.
Continue on to :ref:`quick-tour-label`.

.. _git: https://git-scm.com/
