Can a contract auto execute a transaction given certain conditions? [duplicate]

Question

I've tried searching for this question but can't seem to find an answer.

There are others asking to auto execute based on an hour interval or other real world check.

What I would like to do is have a contract sitting with an existing balance of ETH watching the balance of another contract. If that balance of contract2 drops below a certain threshold on the next block I'd like contract1 to auto execute a send to bring the balance of contract2 back up.

Basically what I'm asking is if the behaviour of a contract auto evaluates the state of other contracts that it's built to monitor and based on its own logic make a decision to execute a transaction given certain conditions of that contract's state? Does it do that evaluation every block or do I have to build a script to ping infura every few seconds even if there isn't a new block?

Answer 1

Smart contracts can not autoexecute, they should always be triggered by a transaction.

In your case you have a contract A and a contract B. When contract B balance is below a particular values you want contract A to do something. The easiest way to do this is to write a function in contract B to call contract A everytime that contract B is called. Like this A can execute it's work if B balance is below the threshold that you define.

Hope this helps