Is it possible to use an existing contracts storage as the seed data for a new contract that has the same storage schema?

Question

Can you deploy a new copy of a contract with SmartPy and simultaneously copy the storage of an already existing contract that has an identical model into the freshly deployed contract?

Answer 1

Yes, it is possible if you originate a contract from within a contract:

The example below duplicates the storage of Creator when originating Created. (This will not work if the storage contains tickets, only duplicable types are allowed)

import smartpy as sp

class Created(sp.Contract):
    def __init__(self):
        self.init(sp.big_map())

    @sp.entry_point
    def update(self):
        self.data[1] -= 1

class Creator(sp.Contract):
    def __init__(self):
        self.init(sp.big_map({1: 2}))

    @sp.entry_point
    def create(self):
        sp.create_contract(Created(), storage = self.data, amount = sp.amount)

    @sp.entry_point
    def update(self):
        self.data[1] += 1

sp.add_compilation_target("Creator", Creator())

Doing this off-chain is more complicated. You will need to query the contract storage with /chains/main/blocks/head/context/contracts/<some_contract>/storage, and if it contains any big_map, you will need to replace the { "int": <big_map_id> } with the expanded map value by querying every big_map entry with /chains/main/blocks/head/context/big_maps/<big_map_id>. (Gas and storage will be a limitation if the big_map has many entries)