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Program Escrow — Circuit Breaker

This document describes the circuit breaker, admin reset, and security model for the program-escrow contract.

Overview​

The circuit breaker protects payout operations from cascading failures by tracking consecutive failures and moving through three states:

  • Closed — normal operation
  • Open — all protected operations rejected (requires admin action)
  • HalfOpen — trial period; successes move to Closed, failures re-open and restart the recovery timeout

The circuit breaker lives in persistent storage under keys defined in error_recovery::CircuitBreakerKey.

Admin Hard Reset: reset_circuit_breaker​

We added an admin-only entrypoint to immediately reset the circuit breaker to Closed and clear failure counters.

  • Signature: reset_circuit_breaker(env: Env, program_id: String) -> Result<(), Error>
  • Authorization: caller must be the contract admin (value stored at DataKey::Admin) and must sign the transaction.
  • Effects:
    • Calls into error_recovery::close_circuit() which sets state to Closed, clears FailureCount and SuccessCount, and clears OpenedAt.
    • Additionally ensures FailureCount is zero (defensive).
    • Emits an audit event (circuit, admin_reset) with payload (program_id, admin_address, timestamp).

Security Notes​

  • Only the contract admin can call this entrypoint; the admin address is read from instance storage and require_auth() is enforced.
  • The function performs a defensive clear of failure counters and emits a deterministic, auditable event so off-chain monitors can verify the manual reset.
  • Prefer manual resets only after a root-cause investigation; use HalfOpen trial behavior for staged recovery when appropriate.

Tests​

Unit tests were added under contracts/program-escrow/src/test_admin_reset.rs verifying that:

  • An admin-authorized reset transitions an Open circuit to Closed and clears counters.
  • A non-authorized caller cannot reset the circuit (panics / is rejected).

Additional enforcement tests now cover the full HalfOpen lifecycle:

  • Open → HalfOpen after recovery_window elapses
  • HalfOpen → Closed on a successful probe
  • HalfOpen → Open on a failed probe, with the open timer reset

Note: the repository contains many existing tests; depending on the environment some test suites may not compile or run fully.

Implementation Notes​

  • The implementation reuses error_recovery::close_circuit() for the state transition and counter resets.
  • The audit event topic admin_reset is stable and includes the program_id to help indexers correlate the reset to a program context.

If you want, I can also update integration tests to exercise the end-to-end flow for batch_payout/single_payout interactions with the breaker.