How to Upgrade a Smart Contract

How to Upgrade Smart Contract

Version 0.1

1. Introduction

API	Return Value	Description
Destroy	none	Destroy a smart contract
Migrate	bool	Upgrade a smart contract. The existing contract will be replaced by the newly migrated contract

For more details, you can view the API-doc and the source code here.

2. Destroy

The existing contract will be deleted from the persistent storage area.

Example

from ontology.interop.Ontology.Contract import Migrate
from ontology.interop.System.Contract import Destroy
from ontology.interop.System.Runtime import Notify

def Main(operation, args):
    if operation == "destroy_contract":
        return destroy_contract()
    
    return False


def destroy_contract():
    Destroy()
    Notify(["The contract has been destoryed"])
    return True

3. Migrate

The existing contract will be replaced by the newly migrated contract. The data saved by the old contract will also be migrated to the new contract. The old contract will be deleted after migration.

Migrate parameters

Param	Description
script	avm code
need_storage	Need persistent storage or not
name	Author name
version	Contract version
author	Contract author
email	Developer email
description	Contract description

Example

from ontology.interop.Ontology.Contract import Migrate
from ontology.interop.System.Contract import Destroy
from ontology.interop.System.Runtime import Notify

def Main(operation, args):
    if operation == "migrate_contract":
        if len(args) != 7:
            return False
        avm_code = args[0]
        need_storage = args[1]
        name = args[2]
        version = args[3]
        author = args[4]
        email = args[5]
        description = args[6]
        return migrate_contract(avm_code)
        
    return False


def migrate_contract(avm_code, need_storage, name, version, author, email, description):
    res = Migrate(avm_code, need_storage, name, version, author, email, description)
    if res:
        Notify(["Migrate successfully"])
        return True
    else:
        return False

Follow up question: How to improve this contract?
Answer: Add CheckWitness().