What kind of external services are we allowed to use in fabric? Can we use any APIs? Or we must just use fabric SDK.
For example, an external service is a bank ATM API, and our transaction is calling the ATM withdrawal operation.
We have defined in our policies that four endorsers must approve it. When the endorser nodes call that external service, are the withdrawal operations performed four times separately; and change the bank account's balance outside the blockchain each time? (so we have trouble in the commitment phase) How can we handle external calls?
I appreciate any help you can provide.