This tutorial assumes that you have already followed the steps in Installing Pyramid, thereby satisfying the following requirements.
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.
$ export VENV=~/pyramidtut
$ virtualenv --no-site-packages $VENV
New python executable in /home/foo/env/bin/python
Installing setuptools.............done.
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 --no-site-packages %VENV%
Python 3.2:
c:\> c:\Python32\Scripts\virtualenv --no-site-packages %VENV%
$ $VENV/bin/easy_install pyramid
c:\env> %VENV%\Scripts\easy_install pyramid
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
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”.
$ $VENV/bin/pcreate -s alchemy tutorial
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.
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.
$ cd tutorial
$ $VENV/bin/python setup.py develop
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
After you’ve installed the project in development mode, you may run the tests for the project.
$ $VENV/bin/python setup.py test -q
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
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:
$ $VENV/bin/easy_install nose coverage
c:\pyramidtut\tutorial> %VENV%\Scripts\easy_install nose coverage
Once nose and coverage are installed, we can actually run the coverage tests.
$ $VENV/bin/nosetests --cover-package=tutorial --cover-erase --with-coverage
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.
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):
$ $VENV/bin/initialize_tutorial_db development.ini
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).
Start the application.
$ $VENV/bin/pserve development.ini --reload
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.
Creating a project using the alchemy scaffold makes the following assumptions:
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.