Question

what was the bargain struck between Shylock and Antonio? ​

Answer 1

Antonio wanted to borrow some money from Shylock because Shylock was worked as a moneylender. In spite of need for Shylock, Antonio cursed him for being a moneylender who charged interest after landing money.

But Shylock handled his abuse because he was a Jewish and suffered this insult patiently.  Antonio abused very badly by Shylock and even he spat on Shylock because he landed out money that belonged to Antonio.