Deployments¶

In smart contract development, users often want to interact with contracts they’ve recently deployed, and keep track of them, so moccasin comes with a built-in sqlite3 database.

Any time you deploy a smart contract, so long as you have your save_to_db flag set to true in your config </api_reference/config_reference>, moccasin will automatically save your deployments to the database. Here is an example moccasin.toml file:

[networks.pyevm]
save_to_db = false # Local and forked networks default to false

[networks.anvil]
save_to_db = true # Any other network default to true
db_path = ".deployments.db"

Getting a deployment by contract name¶

You can then, get your latest deployment with any of the following options:

from moccasin.config import get_config
from boa.contracts.abi.abi_contract import ABIContract
# from boa.deployments import Deployment


def moccasin_main():
    config = get_config()
    active_network = config.get_active_network()

    # Get the latest counter of the Counter contract
    counter_contract: ABIContract = active_network.get_latest_contract_unchecked("Counter")

This will get you a counter_contract object that you can interact with. It will look in the database and return the most recently deployed contract on the network that your script is active on. It’ll assign the ABI of your contract when you deployed it to the bytecode at that address.

There are a number of functions we can call to get either a ABIContract or Deployment object.

get_deployments_unchecked: This will return all deployments for a given contract name, without checking checking integrity.
get_deployments_checked: This will return all deployments for a given contract name, checking checking integrity.
get_latest_deployment_checked: This will return the latest deployment for a given contract name, checking checking integrity.
get_latest_deployment_unchecked: This will return the latest deployment for a given contract name, without checking checking integrity.
get_latest_contract_checked: This will return the latest contract for a given contract name, checking checking integrity. It will convert the Deployment object to an ABIContract.
get_latest_contract_unchecked: This will return the latest contract for a given contract name, without checking checking integrity. It will convert the Deployment object to an ABIContract.
get_or_deploy_named_contract/ manifest_named: This “magical” function will either check the database for a contract, deploy it, check your named contracts, and a few other places, and if it doesn’t find a contract, it will deploy the contract for you. You can read more about it here.

Checked vs Unchecked¶

When developing, you’ll often make changes to your smart contracts, and you may want to only interact with a contract that matches your current working contract. For example, I could have this code in a file called Counter.vy:

# SPDX-License-Identifier: MIT
# pragma version 0.4.0
number: public(uint256)
@external
def set_number(new_number: uint256):
    self.number = new_number


@external
def increment():
    self.number += 1

And deploy it as contract A, then, change it:

# SPDX-License-Identifier: MIT
# pragma version 0.4.0
number: public(uint256)
@external
def set_number(new_number: uint256):
    self.number = new_number

And deploy it as contract B.

Now, when I call get_deployments_checked on Counter, it will only return 1 contract, contract B since that matches the contract that is in my current Counter.vy file.

But, if I call get_deployments_unchecked on Counter, it will return both contract A and contract B! Since that will only return deployments based on the contract_name (filename). The way this works, is that under the hood, moccasin does an integrity check by calling has_matching_integrity on the Network class, which compares a hash of each of the contract bytecodes to each other.