Fast USDC

Development package for the Fast USDC product. Here in agoric-sdk as a convenience for integration testing and iterating on the SDK affordances required for the product.

Factoring

This package is meant to contain all the code for the Fast USDC product. However there are some constraints:

• a3p integration tests are in the a3p-integration top-level package, separate from this workspace
• the proposal builders are in @agoric/builders to work with the a3p-integration build:submissions script
• the RunUtils tests are in @agoric/boot to test running them atop a fresh bootstrapped environment

Over time we can update our tooling to decouple this more from the packages directory.

1. Make a3p-integration build:submissions script work with arbitrary builder paths, allowing this to be above @agoric/builders in the package graph
2. Export bootstrap testing utilities from @agoric/boot, allowing this to be above @agoric/boot in the package graph
3. Update CI to support packages that aren't under packages/, eg. a top-level dapps directory
4. Move this package out of agoric-sdk

Transaction feed

Oracles interface

Oracles run off-chain and interact with the contract via an Agoric smart wallet bridge.

sequenceDiagram
    title Becoming an oracle operator
    participant OW as Operator N
Smart Wallet
    participant FUC as Fast USDC
Contract Exo
    participant CE as Core Eval

    CE->>FUC: makeOperatorInvitation()
    FUC-->>CE: operatorInvitation
    CE->>+OW: deposit(operatorInvitation)

    Note left of FUC: Off-chain wallet accepts the operator invitation

    OW->>+FUC: offer(operatorInvitation)
    FUC-->>OW: operator invitationMakers: {SubmitEvidence}

    Note left of FUC: Off-chain watcher detects evidence
    OW->>+FUC: offer(SubmitEvidence, evidence)
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sequenceDiagram
    title Receiving evidence
    participant W as Operator N
Smart Wallet
    participant A as Operator N
Admin Oexo
    participant TF as Transaction
Feed

    W->>A: offer(SubmitEvidence, evidence)

    Note left of A: Once 3 operators push the same…

    A->>TF: notify(evidence)
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Status Manager

Pending Advance State Diagram

Transactions are qualified by the OCW and EventFeed before arriving to the Advancer.

stateDiagram-v2
  [*] --> Observed: observe()
  [*] --> Advancing: advancing()

  Advancing --> Advanced: advanceOutcome(...true)
  Advancing --> AdvanceFailed: advanceOutcome(...false)

  Observed --> [*]: dequeueStatus()
  Advanced --> [*]: dequeueStatus()
  AdvanceFailed --> [*]: dequeueStatus()

  note right of [*]
    After dequeueStatus():
    Transaction is removed 
    from pendingTxs store.
    Settler will .disburse()
    or .forward()
  end note
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Complete state diagram (starting from Transaction Feed into Advancer)

stateDiagram-v2
  Observed --> AdvanceSkipped : Risks identified
  Observed --> Advancing : No risks, can advance
  Observed --> Forwarding : No risks, Mint deposited before advance
  Forwarding --> Forwarded
  Advancing --> Advanced
  Advanced --> Disbursed
  AdvanceSkipped --> Forwarding : Mint deposited
  AdvanceFailed --> Forwarding : Mint deposited
  Advancing --> AdvanceFailed
  Forwarding --> ForwardFailed
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