Framework
Actions

Actions

Actions are proposed, executable transactions that can be initiated by policyholders.

They can define any arbitrary operation, such as transferring funds, updating a registry, changing protocol parameters, or activating an emergency pause. Actions are how your Llama instance interacts with external contracts.

Actions are composed of the following parameters:

  • Target Contract: Contract to be called by the Llama executor.
  • Strategy: Contract that determines the rules the action must follow.
  • Calldata: Function selector and its parameters.
  • Role: Role used to create the action.
  • Value: Amount of Ether (in wei) sent with the call.
  • Description: Markdown text explaining the purpose of the action.

Key Concepts

  • Llama Instance: The unique LlamaCore, LlamaPolicy, and LlamaExecutor addresses for a deployment.
  • LlamaCore (opens in a new tab): Manages the action process from creation to execution.
    • Actions: Proposals made by policyholders to execute onchain transactions.
    • Strategies: A contract that holds all of the logic to determine the rules and state of an action. For example, strategies determine whether or not an action is approved/disapproved, canceled, or able to be executed. They also determine details around who is allowed to cast approvals/disapprovals.
    • Guards: Guards enable custom safety checks and logic to run at action creation, pre-execution, and post-execution. Guards can also be used to add arbitrary logic such as spending limits or calldata permissioning.
    • Scripts: Contracts that are delegatecalled from the Executor instead of called. Scripts can be used to batch calls together for extended functionality.
  • LlamaPolicy (opens in a new tab): An ERC721 contract where each token is non-transferable, and defines the roles permissions held by the policyholder. Roles can be permissioned to create, approve and disapprove actions.
    • Policies: Non-transferable NFTs encoded with roles and permission IDs for an individual Llama instance.
    • Roles: A signifier that is used to permission action creation, approval, and disapproval. Any role can be given to one or more policyholders.
    • Permission IDs: A unique identifier that can be assigned to roles to enable action creation. Permission IDs are represented as a hash of the target contract, function selector, and strategy contract. Actions cannot be created unless a policyholder holds a role with the correct permission.
  • LlamaExecutor (opens in a new tab): The single exit point of a Llama instance. All actions that are executed will be sent from the Llama executor. This is the address that should be the owner or other privileged role in a system controlled by the llama instance.
  • approvalPeriod: The length of time that policyholders can approve an action.
  • queuingPeriod: The inverse of the approval period that can also be thought of as the disapproval period; defines the amount of time that policyholders have to disapprove an action.

Action State

Action State Diagram

At any time an action is in one of seven states, represented by the following enum:

enum ActionState {
  Active,
  Canceled,
  Failed,
  Approved,
  Queued,
  Expired,
  Executed
}

Lets dive into each state and what they mean.

  • Active: The default state after an action has been created. This is when policyholders can approve the action. If the action is not approved by the end of the approval period, the action will enter the Failed state.
  • Canceled: The action creator has the opportunity to cancel the action at any time during the action lifecycle. Once an action has been canceled, it cannot be executed. Reached by successfully calling cancelAction.
  • Failed: An action reaches the failed state if it does not reach the approval quorum by the end of the approval period, or if the action gets disapproved during the queuing period. Once an action has reached the failed state, it cannot be executed.
  • Approved: The action has been approved and is ready to be queued.
  • Queued: The action is in the Queued state during the queueing period, which is when policyholders can disapprove the action. If the action is disapproved it will fail, otherwise it can be executed after the queuing period ends. Reached by successfully calling queueAction.
  • Expired: The queuing period has elapsed, but the action was not executed. This occurs when a strategy's isActionExpired method returns true.
  • Executed: This state signifies that the action has been executed successfully. Reached by successfully calling executeAction.

We can call the getActionState method on LlamaCore to get the current state of a given action.

Permissioning Action Creation

Permission IDs are the atomic unit for action creation access control and are managed through the LlamaPolicy contract. Permission IDs can be assigned to roles, roles are assigned to policies, and externally-owned accounts and smart contracts (users) hold policies. Policies can have zero or many roles, and roles can have zero or many permission IDs. When creating an action, LlamaCore performs a validation check is done to make sure that the policyholder has a role with the correct permission. Additional checks may be run by the strategy or a guard.

Permission IDs are calculated by taking the keccak256 hash of the ABI-encoded PermissionData struct, which looks like this:

struct PermissionData {
  address target; // Contract being called by an action.
  bytes4 selector; // Selector of the function being called by an action.
  ILlamaStrategy strategy; // Strategy used to govern the action.
}

When creating an action, the permission required to create said action can be calculated on the fly, since the action creator must pass in the target, selector & strategy. LlamaCore calculates the permission ID at action creation. It uses this to check the canCreateAction mapping on the LlamaPolicy contract to verify that the action creation role has the corresponding permission.

To grant or revoke the ability to create actions with a given Permission ID from a role, we use the setRolePermission function on the LlamaPolicy contract.

To authorize and unauthorize strategies, we use the setStrategyAuthorization function on the LlamaCore contract by passing a bool to determine if the strategy should be authorized or unauthorized

Approvals and Disapprovals

The ability to cast approvals and disapprovals will typically be controlled by roles defined in a ILlamaStrategy contract and are set explicitly on the strategy contract at deployment. Each strategy can have exactly one approval role and one disapproval role. Policyholders with the correct approval/disapproval roles are able to cast their approvals/disapprovals on the action, which determines whether or not the action passes or fails. Policyholders without the correct approval/disapproval role are not able to cast.

Note: The strategy behavior defined in this section is true for the existing strategy implementation but does not have to be true for future implementations.

Force Approval/Disapproval Roles

Strategies have a concept of force approval/disapproval roles in addition to the normal approval/disapproval roles. A strategy can have many force approval/disapproval roles, unlike the normal approval/disapproval roles which are limited to one. Like the name suggests, if a policyholder with a force role casts their approval/disapproval the strategy will immediately reach the respective quorum.

Scripts

Scripts are the term used to refer to target contracts that are called via DELEGATECALL instead of a normal CALL. The main use-case for scripts is to batch multiple calls together into one action. In particular, scripts should be used to batch calls that are regularly made in tandem with one another to perform maintenance or other recurring tasks.

DELEGATECALL is dangerous to use by default, so scripts must be authorized before use. To authorize a script, a policyholder must create an action that calls the setScriptAuthorization function on LlamaCore. Scripts may also be unauthorized using the same function.

Guards

Guards are optional hooks that can run at action creation, pre-action execution, and post-action execution. They can be set on any target address and function selector pair. The main use case for guards is to extend the Llama permission system. Guards can effectively permission calldata, such as implementing a spending limit per transaction in the validatePreActionExecution function, or verifying the final state of a DeFi transaction is as expected in validatePostActionExecution.

Guards have one limitation in that they cannot be used to guard calls to the core or policy contract, since a malfunctioning guard could brick your Llama instance if it were able to guard a core function such as setRolePermission or setGuard itself.

Llama recommends using guards to implement adhoc and protocol specific safety checks.