import urllib.request

url = "http://generic_url:port/?action=stream"

username = "user"
password = "pass"

passman = urllib.request.HTTPPasswordMgrWithDefaultRealm()
passman.add_password(None, url,username,password)

auth_handler = urllib.request.HTTPBasicAuthHandler(passman)

opener = urllib.request.build_opener(auth_handler)

urllib.request.install_opener(opener)

pagehandle = urllib.request.urlopen(url)

contents = pagehandle.read()