How To Obtain A Guangzhou Visa

I am a Canadian resident with a Canadian passport that is looking to travel to Guangzhou for the Canton fair from October 16th to October 18th.

Will I be able to get a Visa from Shenzhen border and then go travel to Guangzhou or do I have to get a Visa specifically for Guangzhou? What is the process like? I will have to do this at the border as I do not have enough time to get this Visa process done in Canada.