Connect to service bus using python SAS token - azure

Question

I need to connect to azure service bus using SAS token(generate and connect).
I don't see anything for the python implementation.
This link provides the implementation for Eventhubs -
https://learn.microsoft.com/en-us/rest/api/eventhub/generate-sas-token#python
Not sure where I can find the python implementation for servicebus.

Answer 1

I have found a way where you can do it for the ServiceBusService Class.
After running "pip install azure.servicebus", I imported it as:
from azure.servicebus.control_client import ServiceBusService
The ServiceBusService constructor takes an argument called "authentication", which isn't specified by default.
If you got into the ServiceBusService init file, you can see how authentication is handled in more detail.
if authentication:
self.authentication = authentication
else:
if not account_key:
account_key = os.environ.get(AZURE_SERVICEBUS_ACCESS_KEY)
if not issuer:
issuer = os.environ.get(AZURE_SERVICEBUS_ISSUER)
if shared_access_key_name and shared_access_key_value:
self.authentication = ServiceBusSASAuthentication(
shared_access_key_name,
shared_access_key_value)
elif account_key and issuer:
self.authentication = ServiceBusWrapTokenAuthentication(
account_key,
issuer)
If you don't pass a custom authentication object, it will then try to use the ServiceBusSASAuthentication class, which is the default if you populate the shared_access_key_name and shared_access_key_value.
So if you jump into the ServiceBusSASAuthentication class, you'll notice something useful.
class ServiceBusSASAuthentication:
def __init__(self, key_name, key_value):
self.key_name = key_name
self.key_value = key_value
self.account_key = None
self.issuer = None
def sign_request(self, request, httpclient):
request.headers.append(
('Authorization', self._get_authorization(request, httpclient)))
def _get_authorization(self, request, httpclient):
uri = httpclient.get_uri(request)
uri = url_quote(uri, '').lower()
expiry = str(self._get_expiry())
to_sign = uri + '\n' + expiry
signature = url_quote(_sign_string(self.key_value, to_sign, False), '')
auth_format = 'SharedAccessSignature sig={0}&se={1}&skn={2}&sr={3}' # <----awww, yeah
auth = auth_format.format(signature, expiry, self.key_name, uri)
return auth # <--after inserting values into string, the SAS Token is just returned.
def _get_expiry(self): # pylint: disable=no-self-use
'''Returns the UTC datetime, in seconds since Epoch, when this signed
request expires (5 minutes from now).'''
return int(round(time.time() + 300))
The sign_request function is the only function that will be directly referenced by the ServiceBusService class when it does authentication, but you'll notice that all its doing is adding an authentication header to a request that...IS IN THE FORMAT OF A SAS TOKEN.
So at this point I had all the information I needed to make my own authentication class. I made one that looked exactly like this.
class ServiceBusSASTokenAuthentication:
def __init__(self, sas_token):
self.sas_token = sas_token
# this method is the one used by ServiceBusService for authentication, need to leave signature as is
# even though we don't use httpClient like the original.
def sign_request(self, request, httpclient):
request.headers.append(
('Authorization', self._get_authorization())
)
def _get_authorization(self):
return self.sas_token
I probably could get rid of the _get_auth function all together, but I haven't polished everything up yet.
So now if you call this class like so in the ServiceBusService constructor with a valid SAS Token, it should work.
subscription_client = ServiceBusService(
authentication=ServiceBusSASTokenAuthentication(sas_token=sas_token),
service_namespace=service_namespace
)

Answer 2

Once you create the Service Bus using Azure Portal, ServiceBusService object enables you to work with queues.
Follow this document for more information on creating the queue, sending message to queue, receiving message from a queue using python to programmatically access the Service Bus.