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Installation

Before You Begin

This tutorial assumes that you have already followed the steps in Installing Pyramid, thereby satisfying the following requirements.

Create and Use a Virtual Python Environment

Next let's create a virtualenv workspace for our project. We will use the VENV environment variable instead of absolute path of the virtual environment.

On UNIX

$ export VENV=~/pyramidtut
$ virtualenv $VENV
New python executable in /home/foo/env/bin/python
Installing setuptools.............done.

On Windows

Set the VENV environment variable.

c:\> set VENV=c:\pyramidtut

Versions of Python use different paths, so you will need to adjust the path to the command for your Python version.

Python 2.7:

c:\> c:\Python27\Scripts\virtualenv %VENV%

Python 3.2:

c:\> c:\Python32\Scripts\virtualenv %VENV%

Install Pyramid Into the Virtual Python Environment

On UNIX

$ $VENV/bin/easy_install pyramid

On Windows

c:\env> %VENV%\Scripts\easy_install pyramid

Install SQLite3 and Its Development Packages

If you used a package manager to install your Python or if you compiled your Python from source, then you must install SQLite3 and its development packages. If you downloaded your Python as an installer from python.org, then you already have it installed and can proceed to the next section Making a Project..

If you need to install the SQLite3 packages, then, for example, using the Debian system and apt-get, the command would be the following:

$ sudo apt-get install libsqlite3-dev

Change Directory to Your Virtual Python Environment

Change directory to the pyramidtut directory.

On UNIX

$ cd pyramidtut

On Windows

c:\> cd pyramidtut

Making a Project

Your next step is to create a project. For this tutorial we will use the scaffold named alchemy which generates an application that uses SQLAlchemy and URL dispatch.

Pyramid supplies a variety of scaffolds to generate sample projects. We will use pcreate—a script that comes with Pyramid to quickly and easily generate scaffolds usually with a single command—to create the scaffold for our project.

By passing in alchemy into the pcreate command, the script creates the files needed to use SQLAlchemy. By passing in our application name tutorial, the script inserts that application name into all the required files. For example, pcreate creates the initialize_tutorial_db in the pyramidtut/bin directory.

The below instructions assume your current working directory is the "virtualenv" named "pyramidtut".

On UNIX

$ $VENV/bin/pcreate -s alchemy tutorial

On Windows

c:\pyramidtut> %VENV%\pcreate -s alchemy tutorial

Note

If you are using Windows, the alchemy scaffold may not deal gracefully with installation into a location that contains spaces in the path. If you experience startup problems, try putting both the virtualenv and the project into directories that do not contain spaces in their paths.

Installing the Project in Development Mode

In order to do development on the project easily, you must "register" the project as a development egg in your workspace using the setup.py develop command. In order to do so, cd to the tutorial directory you created in Making a Project, and run the setup.py develop command using the virtualenv Python interpreter.

On UNIX

$ cd tutorial
$ $VENV/bin/python setup.py develop

On Windows

c:\pyramidtut> cd tutorial
c:\pyramidtut\tutorial> %VENV%\Scripts\python setup.py develop

The console will show setup.py checking for packages and installing missing packages. Success executing this command will show a line like the following:

Finished processing dependencies for tutorial==0.0

Running the Tests

After you've installed the project in development mode, you may run the tests for the project.

On UNIX

$ $VENV/bin/python setup.py test -q

On Windows

c:\pyramidtut\tutorial> %VENV%\Scripts\python setup.py test -q

For a successful test run, you should see output that ends like this:

.
----------------------------------------------------------------------
Ran 1 test in 0.094s

OK

Exposing Test Coverage Information

You can run the nosetests command to see test coverage information. This runs the tests in the same way that setup.py test does but provides additional "coverage" information, exposing which lines of your project are "covered" (or not covered) by the tests.

To get this functionality working, we'll need to install the nose and coverage packages into our virtualenv:

On UNIX

$ $VENV/bin/easy_install nose coverage

On Windows

c:\pyramidtut\tutorial> %VENV%\Scripts\easy_install nose coverage

Once nose and coverage are installed, we can actually run the coverage tests.

On UNIX

$ $VENV/bin/nosetests --cover-package=tutorial --cover-erase --with-coverage

On Windows

c:\pyramidtut\tutorial> %VENV%\Scripts\nosetests --cover-package=tutorial \
      --cover-erase --with-coverage

If successful, you will see output something like this:

.
Name               Stmts   Miss  Cover   Missing
------------------------------------------------
tutorial              11      7    36%   9-15
tutorial.models       17      0   100%
tutorial.scripts       0      0   100%
tutorial.tests        24      0   100%
tutorial.views         6      0   100%
------------------------------------------------
TOTAL                 58      7    88%
----------------------------------------------------------------------
Ran 1 test in 0.459s

OK

Looks like our package doesn't quite have 100% test coverage.

Initializing the Database

We need to use the initialize_tutorial_db console script to initialize our database.

Type the following command, make sure you are still in the tutorial directory (the directory with a development.ini in it):

On UNIX

$ $VENV/bin/initialize_tutorial_db development.ini

On Windows

c:\pyramidtut\tutorial> %VENV%\Scripts\initialize_tutorial_db development.ini

The output to your console should be something like this:

2011-11-26 14:42:25,012 INFO  [sqlalchemy.engine.base.Engine][MainThread]
                              PRAGMA table_info("models")
2011-11-26 14:42:25,013 INFO  [sqlalchemy.engine.base.Engine][MainThread] ()
2011-11-26 14:42:25,013 INFO  [sqlalchemy.engine.base.Engine][MainThread]
CREATE TABLE models (
      id INTEGER NOT NULL,
      name VARCHAR(255),
      value INTEGER,
      PRIMARY KEY (id),
      UNIQUE (name)
)
2011-11-26 14:42:25,013 INFO  [sqlalchemy.engine.base.Engine][MainThread] ()
2011-11-26 14:42:25,135 INFO  [sqlalchemy.engine.base.Engine][MainThread]
                              COMMIT
2011-11-26 14:42:25,137 INFO  [sqlalchemy.engine.base.Engine][MainThread]
                              BEGIN (implicit)
2011-11-26 14:42:25,138 INFO  [sqlalchemy.engine.base.Engine][MainThread]
                              INSERT INTO models (name, value) VALUES (?, ?)
2011-11-26 14:42:25,139 INFO  [sqlalchemy.engine.base.Engine][MainThread]
                              (u'one', 1)
2011-11-26 14:42:25,140 INFO  [sqlalchemy.engine.base.Engine][MainThread]
                              COMMIT

Success! You should now have a tutorial.sqlite file in your current working directory. This will be a SQLite database with a single table defined in it (models).

Starting the Application

Start the application.

On UNIX

$ $VENV/bin/pserve development.ini --reload

On Windows

c:\pyramidtut\tutorial> %VENV%\Scripts\pserve development.ini --reload

If successful, you will see something like this on your console:

Starting subprocess with file monitor
Starting server in PID 8966.
Starting HTTP server on http://0.0.0.0:6543

This means the server is ready to accept requests.

At this point, when you visit http://localhost:6543/ in your web browser, you will see the generated application's default page.

One thing you'll notice is the "debug toolbar" icon on right hand side of the page. You can read more about the purpose of the icon at The Debug Toolbar. It allows you to get information about your application while you develop.

Decisions the alchemy Scaffold Has Made For You

Creating a project using the alchemy scaffold makes the following assumptions:

  • you are willing to use SQLAlchemy as a database access tool
  • you are willing to use url dispatch to map URLs to code.
  • you want to use ZopeTransactionExtension and pyramid_tm to scope sessions to requests

Note

Pyramid supports any persistent storage mechanism (e.g. object database or filesystem files, etc). It also supports an additional mechanism to map URLs to code (traversal). However, for the purposes of this tutorial, we'll only be using url dispatch and SQLAlchemy.