to address the OP:
Cannabis is mentioned throughout the gemara, rishonim and achronim. The gemara menachos 15b, for example:
דתנן
היתה שדהו זרועה קנבוס ולוף לא יהא זורע על גביהם שהן עושות לשלש שנים
The Shulchan Aruch says to beautify the shabbos candles use a wick made of cannabis (although he probably meant hemp).
There is also discussion in the rishonim about using cannabis for skhakh.
All of the above most probably point to hemp being used but was cannabis used the way it is today?
There are some suggestions that yes.
The late achronim debate whether it is kitniyos. The Radbaz, when describing uses of cannabis in relation to kilyaim laws says its used for hemp and also gives a person simcha.
The Rambam talks about cannabis as it relates to kilayim but in his medical writings writes extensively above using it for medicinal purposes.
Rav Moshe, of course, assured it in Yoreh Deah 3:35 for dina demalchusa and also all the reasons given in the comments above.