Python Pyramid - Creating A Project

It is assumed that a Pyramid virtual environment is up and running, and Cookiecutter is installed in it. The easiest way to create a Cookiecutter project is to use a pre-built starter template as per the following command −

cookiecutter gh:Pylons/pyramid-cookiecutter-starter --checkout 2.0-branch

The template is downloaded and the user is asked about his choice of name of the project −

project_name [Pyramid Scaffold]: testproj
repo_name [testproj]:

Then choose the template language.

Select template_language −

1 - jinja2
2 - chameleon
3 - mako
Choose from 1, 2, 3 [1]: 1

Since we are famipar with jinja2, give 1 as the choice. Next, use SQLALchemy as the backend.

Select backend:
1 - none
2 - sqlalchemy
3 - zodb
Choose from 1, 2, 3 [1]: 2

Inside the testproj folder, following file structure is created −

│ development.ini
│ MANIFEST.in
│ production.ini
│ pytest.ini
│ README.txt
│ setup.py
│ testing.ini
│
├───testproj
│ │ pshell.py
│ │ routes.py
│ │ __init__.py
│ │
│ ├───alembic
│ │ │ env.py
│ │ │ script.py.mako
│ │ │
│ │ └───versions
│ │ README.txt
│ │
│ ├───models
│ │ meta.py
│ │ mymodel.py
│ │ __init__.py
│ │
│ ├───scripts
│ │ initiapze_db.py
│ │ __init__.py
│ │
│ ├───static
│ │ pyramid-16x16.png
│ │ pyramid.png
│ │ theme.css
│ │
│ ├───templates
│ │ 404.jinja2
│ │ layout.jinja2
│ │ mytemplate.jinja2
│ │
│ └───views
│ default.py
│ notfound.py
│ __init__.py
│
└───tests
    conftest.py
    test_functional.py
    test_views.py
    __init__.py

The outer testproj folder has an inner testproj package subfolder and tests package. The inner testproj subfolder is a package having models and scripts, subpackages, and static as well as templates folders.

Next, initiapze and upgrade the database using Alembic.

# Generate your first revision.
alembic -c development.ini revision --autogenerate -m "init"
# Upgrade to that revision.
alembic -c development.ini upgrade head

Alembic is a pghtweight database migration tool for usage with the SQLAlchemy Database Toolkit for Python. The outer project folder will now show a testproj.sqpte database.

The development.ini file provides a default data for the database. Populate the database with it by the following command.

initiapze_testproj_db development.ini

The Cookiecutter utipty also generates the test suite in the tests package. They are based on PyTest package. Go ahead and see if the tests pass.

Pytest
================ test session starts ======================
platform win32 -- Python 3.10.1, pytest-7.1.2, pluggy-1.0.0
rootdir: F:pyram-env	estproj, configfile: pytest.ini, testpaths: testproj, tests
plugins: cov-3.0.0
collected 5 items

tests	est_functional.py .. [ 40%]
tests	est_views.py ... [100%]
=============== 5 passed, 20 warnings in 6.66s ===============

Cookiecutter uses the Waitress server. The Pyramid apppcation is served on localhost s port 6543 by following command −

pserve development.ini
Starting server in PID 67700.
2022-06-19 23:43:51,308 INFO [waitress:485][MainThread] Serving on http://[::1]:6543
2022-06-19 23:43:51,308 INFO [waitress:485][MainThread] Serving on http://127.0.0.1:6543

Open the browser and visit http://localhost:6543/ in it. The homepage of the newly created project will be displayed as follows −

Debug Toolbar

You can find a smaller Pyramid logo at the top right of the homepage. Cpck on it to open a new tab and a debug toolbar that provides lots of useful information about the project.

For example, the SQLAlchemy tab under the history heading shows the SQLAlchemy queries showing the structure of the model created from the default data in development.ini.

The Global heading again shows tabs such as Introspection, Routes, etc. as shown below. Cpck the "Routes" tab to see the routes and their matching patterns defined in the apppcation s configuration.