March 2019
Intermediate to advanced
636 pages
27h 50m
English
book
Blockchain Development with Hyperledger
by Salman A. Baset, Luc Desrosiers, Nitin Gaur, Petr Novotny
Content preview from Blockchain Development with Hyperledger
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Ledger resetting
A chaincode upgrade is like instantiation, and both result in the execution of the Init function. In the initial version of the chaincode, many ledger values were initialized, but unless we change that logic, those initial values will overwrite the current state of the ledger. Therefore, we add code to the Init function in chaincode/src/github.com/trade_workflow_v1/tradeWorkflow.go to emulate a no-op, but we also leave the original logic intact to ensure that values can be overwritten during an upgrade if there is a business need to do so, as the following code snippet illustrates:
func (t *TradeWorkflowChaincode) Init(stub shim.ChaincodeStubInterface) pb.Response { ...... // Upgrade Mode 1: leave ledger state as it was if ...Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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