Instrument Manager
Instrument Manager is the core of a financial instrument management domain. Its main functionalities include:
Manages issuance assets using Issuance Escrows
Manages issuance data using Issuance Storages
Manages issuance lifecycle by delegating issuance operations to Instrument
Controls access to Instruments
Provides standardized Oracle services to Instrument
As NUTS Platform is targeted to become a general financial instrument platform, it should be able to support financial instrument with various complexity and requirements in security, flexibility, ease of development, and etc. Therefore, NUTS Platform has defined multiple Instrument Interface to model the financial instrument and serve as the interface between Instrument Manager and Instrument.
Even though there are multiple Interface Interfaces defined, they share the same set of operations but with different arguments:
Create new issuance
Engage existing issuance
Deposit ETH/ERC20 tokens to existing issuance
Withdraw ETH/ERC20 tokens from existing issuance
Process custom event (any event, including events notified by Timer Oracle)
Get custom data
Instrument Manager Interface is a single interface implemented by all Instrument Managers. Unlike Instrument Interfaces, there is only one Instrument Manager Interface and it defines the functionalities exposed by a financial instrument management domain.
Below are the list of issuance operations defined:
Create new issuance
Engage existing issuance
Deposit ETH/ERC20 tokens to existing issuance
Withdraw ETH/ERC20 tokens from existing issuance
Process custom event (any custom event, including events notified by Timer Oracle)
Get custom data
In short, there is a one-to-one relationship between Instrument Interface methods and the issuance operations defined in Instrument Manager Interface. Instrument Managers manage data and assets for individual issuance, and delegate the actual issuance operation to Instrument.
Instrument Manager Interface defines additional method in addition to issuance operations.
Different Instrument Manager implementations differ in issuance data management but share the same issuance asset management logic.
The assets in an instrument management domain are split into two different kinds of escrows: Instrument Escrow and Issuance Escrow. Instrument Escrow serves as the asset portal of the instrument management domain. Makers/Takers should deposit/withdraw ETH/ERC20 tokens to the Instrument Escrow. Issuance Escrow keeps assets that are locked in an issuance.
Instrument Manager is the owner of all escrows in an instrument management domain. An issuance, similar to any other account, has read access to the Issuance Escrow so that it could check the balance of individual issuance participant. In order to maximize asset security of issuance, only Instrument Manager can deposit/withdraw from an Issuance Escrow. Issuance tells Instrument Manager the desired transfer action to be done, and Instrument Manager completes the transfers on behalf of issuance.
Instrument Manager can perform the following assets operations:
When makers/takers deposit ETH/ERC20 tokens to issuance, Instrument Manager transfers ETH/ERC20 tokens from Instrument Escrow to the targeted Issuance Escrow;
When makers/transfer withdraws ETH/ERC20 tokens from issuance, Instrument Manager transfers ETH/ERC20 tokens from Issuance Escrow to Instrument Escrow;
When certain issuance state is met, issuance might want to change ownership of an asset inside the Issuance Escrow. Instrument Manager complete this on behalf of issuance;
When certain issuance state is met, issuance might want to transfer ETH/ERC20 tokens to other accounts. Instrument Manager transfers ETH/ERC20 tokens from Issuance Escrow to Instrument Escrow.
Instrument Manager adopts Proxy contracts to keep issuance data. While traditional Proxy pattern uses Proxy contract to separate logic and storage, Instrument Manager uses Proxy pattern to separate Issuance data.
When invoking Instrument methods, Instrument Manager does that through the Proxy contracts which delegates calls to Instrument. Each issuance has a dedicated Proxy which keeps data for that issuance.
Instrument Manager allows any Instrument data layout and is thus more flexible than Instrument Type II. In order to enforce access control, only Instrument Manager can invoke methods on Proxy contracts. It's also subject to reentrancy attack and thus suitable for trusted FSPs.
