Adding Resources

The true power of Rotest is in its client-server infrastructure, which enables writing resource-oriented tests, running a dedicated server to hold all resources, and enabling clients run tests.

In this tutorial, you’ll learn:

  • How to create a resource class.
  • How to run the server, that acts as a resource manager.

Creating a Resource Class

In the root of your project, create a new Django application:

$ django-admin startapp resources

You’ll see a new directory named resources, in the following structure:

.
├── manage.py
├── resources
│   ├── admin.py
│   ├── __init__.py
│   ├── migrations
│   │   └── __init__.py
│   ├── models.py
│   ├── tests.py
│   └── views.py
├── rotest_demo
│   ├── __init__.py
│   ├── __init__.pyc
│   ├── settings.py
│   ├── settings.pyc
│   ├── urls.py
│   └── wsgi.py
├── rotest.yml
└── test_math.py

Don’t forget to add the new application as well as rotest to the INSTALLED_APPS configuration in the rotest_demo/settings.py file:

...

INSTALLED_APPS = (
    'rotest.core',
    'rotest.management',
    'resources',
    'django.contrib.admin',
    'django.contrib.auth',
    ...
)

We’re going to write a simple resource of a calculator. Edit the resources/models.py file to have the following content:

from django.db import models
from rotest.management.models import resource_data


class CalculatorData(resource_data.ResourceData):
    class Meta:
        app_label = "resources"

    ip_address = models.IPAddressField()

The CalculatorData class is the database definition of the Calculator resource. It defines any characteristics it has, as oppose to behaviour it may have. It’s also recommended adding it to the Django admin panel. Edit the content of the resources/admin.py file:

from rotest.management.admin import register_resource_to_admin

from . import models

register_resource_to_admin(models.CalculatorData, attr_list=['ip_address'])

Let’s continue to write the Calculator resource, which exposes a simple calculation action. Edit the file resources/calculator.py:

import rpyc
from rotest.management.base_resource import BaseResource

from .models import CalculatorData


class Calculator(BaseResource):
    DATA_CLASS = CalculatorData

    PORT = 1357

    def connect(self):
        self._rpyc = rpyc.classic.connect(self.data.ip_address, self.PORT)

    def calculate(self, expression):
        return self._rpyc.eval(expression)

    def finalize(self):
        if self._rpyc is not None:
            self._rpyc.close()
            self._rpyc = None

Note the following:

  • There is a use in the RPyC module, which can be installed using:

    $ pip install rpyc
    
  • The Calculator class inherits from rotest.management.base_resource.BaseResource.

  • The previously declared class CalculatorData is referenced in this class.

  • Two methods are used to set up and tear down the connection to the resource: rotest.management.base_resource.BaseResource.connect() and rotest.management.base_resource.BaseResource.finalize().

Running the Resource Management Server

First, let’s initialize the database with the following Django commands:

$ python manage.py makemigrations
Migrations for 'resources':
  0001_initial.py:
    - Create model CalculatorData
$ python manage.py migrate
Operations to perform:
  Apply all migrations: core, management, sessions, admin, auth, contenttypes, resources
Running migrations:
  Applying contenttypes.0001_initial... OK
  Applying auth.0001_initial... OK
  Applying admin.0001_initial... OK
  Applying management.0001_initial... OK
  Applying management.0002_auto_20150224_1427... OK
  Applying management.0003_add_isusable_and_comment... OK
  Applying management.0004_auto_20150702_1312... OK
  Applying management.0005_auto_20150702_1403... OK
  Applying management.0006_delete_projectdata... OK
  Applying management.0007_baseresource_group... OK
  Applying management.0008_add_owner_reserved_time... OK
  Applying management.0009_initializetimeoutresource... OK
  Applying management.0010_finalizetimeoutresource... OK
  Applying management.0011_refactored_to_resourcedata... OK
  Applying management.0012_delete_previous_resources... OK
  Applying core.0001_initial... OK
  Applying core.0002_auto_20170308_1248... OK
  Applying management.0013_auto_20170308_1248... OK
  Applying resources.0001_initial... OK
  Applying sessions.0001_initial... OK

The first command creates a migrations file, that orders changing the database schemas or contents. The second command changes the database according to those orders. If the database does not already exist, it creates it.

Let’s run the Rotest server, using the rotest server command:

$ rotest server

Performing system checks...

System check identified no issues (0 silenced).
May 23, 2018 - 20:05:28
Django version 1.7.11, using settings 'rotest_demo.settings'
Starting development server at http://0.0.0.0:8000/
Quit the server with CONTROL-C.

Adding a Resource on Django Admin Panel

To sum this up, let’s add a Calculator resource. Run the createsuperuser command to get access to the admin panel:

$ python manage.py createsuperuser
Username (leave blank to use 'user'): <choose a user in here>
Email address: <choose your email address>
Password: <type in your password>
Password (again): <type password again>
Superuser created successfully.

Now, Just enter the Django admin panel (via http://127.0.0.1:8000/admin), access it using the above credentials, and add a resource with the name calc and a local IP address like 127.0.0.1:

../_images/adding_resource.png

Adding a resource via Django admin