How do I force Django to connect to Oracle using Service Name

Behind the scenes Django uses cx_Oracle library to connect to Oracle database. Source: https://github.com/django/django/blob/master/django/db/backends/oracle/base.py

import cx_Oracle as Database

def _connect_string(self):
        settings_dict = self.settings_dict
        if not settings_dict['HOST'].strip():
            settings_dict['HOST'] = 'localhost'
        if settings_dict['PORT'].strip():
            dsn = Database.makedsn(settings_dict['HOST'],
                                   int(settings_dict['PORT']),
                                   settings_dict['NAME'])
        else:
            dsn = settings_dict['NAME']
        return "%s/%s@%s" % (settings_dict['USER'],
                             settings_dict['PASSWORD'], dsn)

Function cx_Oracle.make_dsn() supports optional parameter service_name (excerpt from cx_Oracle docs):

cx_Oracle.makedsn(host, port, sid[, service_name])

Return a string suitable for use as the dsn for the connect() method. This string is identical to the strings that are defined by the Oracle names server or defined in the tnsnames.ora file. If you wish to use the service name instead of the sid, do not include a value for the parameter sid and use the keyword parameter service_name instead. Note This method is an extension to the DB API definition.

Unfortunately, Django is not passing service_name parameter on connection.

If you really need it, add feature request to Django or patch your local version of Django to support SERVICE_NAME parameter (bad idea, you will need to support it by yourself):

def _connect_string(self):
    settings_dict = self.settings_dict
    if not settings_dict['HOST'].strip():
        settings_dict['HOST'] = 'localhost'
    if settings_dict['PORT'].strip():
        if not 'SERVICE_NAME' in settings_dict:
            dsn = Database.makedsn(settings_dict['HOST'],
                                   int(settings_dict['PORT']),
                                   settings_dict['NAME'])
        else:
            dsn = Database.makedsn(host=settings_dict['HOST'],
                                   port=int(settings_dict['PORT']),
                                   service_name=settings_dict['SERVICE_NAME'].strip())

    else:
        dsn = settings_dict['NAME']
    return "%s/%s@%s" % (settings_dict['USER'],
                         settings_dict['PASSWORD'], dsn)

Then change NAME to SERVICE_NAME variable to your connection 'default':

 'default': {
            'ENGINE': 'django.db.backends.oracle',
            'SERVICE_NAME': 'myservice.bose.com',
            'USER': 'system',
            'PASSWORD': 'admin123',
            'HOST': '192.168.1.45',
            'PORT': '1699',
    }

Later, I am going to add it as a pull request to Django source.

Thanks guys, There's a "documented" solution to this:

        'default': {
                'ENGINE': 'django.db.backends.oracle',
                'NAME': 'host.db.com:1699/oracle_service.db.com',
                'USER': 'user',
                'PASSWORD': 'pass',
        }

Note: The HOST and PORT keys need to be left out of the dictionary - else Django will try connecting with the complete "NAME" as an SID.

Looking at the code that nickzam pasted:

import cx_Oracle as Database

def _connect_string(self):
    settings_dict = self.settings_dict
    if not settings_dict['HOST'].strip():
        settings_dict['HOST'] = 'localhost'
    if settings_dict['PORT'].strip():
        dsn = Database.makedsn(settings_dict['HOST'],
                               int(settings_dict['PORT']),
                               settings_dict['NAME'])
    else:
        dsn = settings_dict['NAME']
    return "%s/%s@%s" % (settings_dict['USER'],
                         settings_dict['PASSWORD'], dsn)

.. it is clear that if you do not specify a 'PORT' parameter, the 'NAME' parameter is used 'as is'. Therefore, passing an Oracle connect string as the 'NAME' parameter will do the trick (if you remove the 'PORT' parameter).

Basically something like this will work:

'default': {
    'ENGINE': 'oraclepool',
    'NAME': '(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=mydbhostname.example.com)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=myservicename.example.com)))',
    'USER': 'scott',
    'PASSWORD': 'tiger',
}

I have tried this using a SCAN hostname for HOST and verified that this works too.

WARNING: My tests so far have been limited to checking whether the connect string is accepted, a connection is made and my app is served successfully, accessing data. Before relying on this configuration I would advise more aggressive testing 8)