Deploying a WebStack Application

The process of deploying a WebStack application should be as straightforward as taking some adapter or "glue" code and either running it or using the deployment processes of the server environment or framework in which the application will be living.

The Adapter Code

What adapter or "glue" code does is to set up your applications main resource object and to hook that object up with the underlying server environment. For the MyApplication example, together with a simple environment, looks something like this:

from WebStack.Adapters.BaseHTTPRequestHandler import deploy    # import the support for the server environment
from MyApplication import MyResource # import the main resource class
print "Serving..."
deploy(MyResource()) # connect a resource object to the server environment

In the case of BaseHTTPRequestHandler, which is a module in the Python standard library, you can just run this code, making sure that the MyApplication module or package is on your PYTHONPATH. Then, you can visit http://localhost:8080 in your browser and see the result.

Root Resources and Site Maps

The above example suggested the direct deployment of a specific resource, and this was quickly achieved by instantiating the resource within the call to the deploy function. However, it may be more desirable to have an application provide a function within the module or package containing the resources which causes their initialisation in a more sophisticated fashion and which returns a resource object ready for use. Let us suppose that the MyApplication module provides a function for this purpose:

from WebStack.Adapters.BaseHTTPRequestHandler import deploy    # import the support for the server environment
from MyApplication import get_site_map # import the function indicating the "root" resource
print "Serving..."
deploy(get_site_map()) # connect a resource object to the server environment

Whilst this appears to be trading one name for another, the intent is really to provide a layer of abstraction which hides the details of resource classes from the deployment code, even if the get_site_map function is only as simple as the following:

def get_site_map():
return MyResource()

Of course, this function may be made more complicated as the need arises.

More Demanding Adapter Code

Unfortunately, not all server environments can be connected up with applications this easily. Some environments require special classes and functions to be defined in the adapter code in order for applications to be properly integrated into those environments. A summary of the requirements of each environment can be found in "Writing Adapters".

The Deployment Process