Upgradability & Opt-in Proxy
Lagoon vaults are Transparent Upgradable Proxy. This type of contract allow there administrator to upgrade the logic used.
Lagoon uses edited versions of the OpenZeppelin Transparent Upgradeable Proxy and ProxyAdmin, allowing them to carry two more features: an Opt-in system and a Delay mechanism.
Opt-in system
Vault administrator can upgrade there vault to a limited set of audited versions, developed and whitelisted by Lagoon.
When a new version is available, the vault admin can choose to upgrade at any time. Rolling back to a previous version is also supported.
Delay mechanism
Every upgrade will take at least 24 hours to be effective and at maximum 30 days. This system ensure that users have time to evaluate the in-coming upgrade and request a redemption it they want to.
This delay itself can be upgraded. This change is also subject to the same delay mechanism.
Design
Opt-in Proxy
The Opt-in Proxy is what you will usually consider as the vault. This contract is a TransparentUpgradbleProxy by OpenZeppelin with two differences. First it doesn't deploy a ProxyAdmin but DelayProxyAdmin. Second, before each implementation update, it will asked the authorization to the ProtocolRegistry, by calling canUseLogic(address oldLogic, address newLogic).
ProtocolRegistry
A protocol level smart-contract that contains a whitelist of authorized implementations.
canUseLogic(address oldLogic, address newLogic) returns (boolean)
This function checks if newLogic is an authorized Lagoon vault version, in this case, it returns true.
DelayProxyAdmin
A Proxy Admin is a smart-contract deployed by an Opt-inProxy at it's creation. This contract is the only address that can upgrade the Opt-inProxy.
The DelayProxyAdmin has an editable owner that is the only one capable of doing the following calls:
submitImplementation(address _implementation) onlyOwner
Submit an address in the DelayProxyAdmin contract. When the delay is passed, the owner can upgrade the contract to this address.
upgradeAndCall(
address proxy,
address,
bytes memory data
) onlyOwner
Upgrade the target proxy using the implementation previously stored via submitImplementation.
submitDelay(
uint256 _delay
) onlyOwner
Submit a new delay. When the current delay is passed, the new delay can be applied.
function updateDelay() onlyOwner
Update the value of the delay to be the one previously submitted via submitDelay.
renounceOwnership() onlyOwner
Renounce the ownership of the DelayAdminProxy making it unusable.
function transferOwnership(address newOwner)
Transfer the ownership and thus the vault upgradability management to another address.
Q&A
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