From 6cc1bea3ddf6cb1ad7c76c7534c067f3a7561b66 Mon Sep 17 00:00:00 2001 From: Kamji Ayuba Gongu <111057335+koder-ns@users.noreply.github.com> Date: Sun, 26 Apr 2026 09:25:28 +0000 Subject: [PATCH] automated admin --- automated.md | 355 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 355 insertions(+) create mode 100644 automated.md diff --git a/automated.md b/automated.md new file mode 100644 index 0000000..f38a262 --- /dev/null +++ b/automated.md @@ -0,0 +1,355 @@ +# Cross-Contract Callback Interface Implementation Summary + +## Overview + +A standardized cross-contract callback interface has been successfully implemented for the StellarFlow Price Oracle. This enables downstream Soroban contracts (Lending protocols, DEXs, etc.) to subscribe to real-time price updates without polling. + +## What's New + +### 1. Core Interface + +**Subscription Functions** (Public API in `PriceOracleClient`): + +```rust +// Register a contract to receive price update callbacks +pub fn subscribe_to_price_updates(callback_contract: Address) -> Result<(), String> + +// Unregister a contract from callbacks +pub fn unsubscribe_from_price_updates(callback_contract: Address) -> Result<(), String> + +// Get list of all subscribed contracts +pub fn get_price_update_subscribers() -> Vec
+``` + +### 2. Standard Callback Interface + +Subscriber contracts must implement: + +```rust +pub fn on_price_update(env: Env, payload: PriceUpdatePayload) +``` + +Where `PriceUpdatePayload` contains: +- `asset`: Symbol (NGN, KES, GHS, etc.) +- `price`: i128 (normalized to 9 decimals) +- `timestamp`: u64 (ledger timestamp) +- `provider`: Address (who submitted the price) +- `decimals`: u32 (always 9) +- `confidence_score`: u32 (0-100) + +### 3. Automatic Callback Invocation + +Callbacks are automatically triggered when prices are updated: +- ✅ `update_price()` - authorized provider updates +- ✅ `set_price()` - admin price setting + +## Architecture + +``` +┌─────────────────────────────────────────────────────────┐ +│ StellarFlow Price Oracle (lib.rs) │ +│ │ +│ ┌────────────────────────────────────────────────┐ │ +│ │ Public Contract Interface │ │ +│ │ - update_price() │ │ +│ │ - set_price() │ │ +│ │ - subscribe_to_price_updates() │ │ +│ │ - unsubscribe_from_price_updates() │ │ +│ │ - get_price_update_subscribers() │ │ +│ └────────────────────────────────────────────────┘ │ +│ ↓ │ +│ ┌────────────────────────────────────────────────┐ │ +│ │ Callbacks Module (callbacks.rs) │ │ +│ │ - subscribe() │ │ +│ │ - unsubscribe() │ │ +│ │ - get_subscribers() │ │ +│ │ - notify_subscribers() │ │ +│ │ - try_invoke_callback() │ │ +│ └────────────────────────────────────────────────┘ │ +│ ↓ │ +│ ┌────────────────────────────────────────────────┐ │ +│ │ Types Module (types.rs) │ │ +│ │ - PriceUpdatePayload │ │ +│ │ - DataKey::PriceUpdateSubscribers │ │ +│ └────────────────────────────────────────────────┘ │ +│ │ +└─────────────────────────────────────────────────────────┘ + ↓ + ┌──────────────────┬──────────────────┐ + ↓ ↓ ↓ + Lending DEX/AMM Other + Protocol Protocol Protocols + + on_price_update() callbacks +``` + +## File Structure + +``` +contracts/price-oracle/src/ +├── lib.rs (Main contract, updated) +│ └── Subscription functions +│ └── Callback integration +├── types.rs (Updated) +│ └── PriceUpdatePayload struct +│ └── DataKey::PriceUpdateSubscribers +├── callbacks.rs (NEW) +│ └── Subscription management +│ └── Callback invocation +├── auth.rs +├── math.rs +├── median.rs +├── asset_symbol.rs +└── test.rs (Extended) + └── 11 new callback tests + +CALLBACK_INTERFACE.md (NEW) +└── Comprehensive documentation +``` + +## Quick Start + +### For Lending Protocol Developers + +1. **Implement callback in your contract**: + ```rust + #[contract] + pub struct MyLendingPool; + + #[contractimpl] + impl MyLendingPool { + pub fn on_price_update(env: Env, payload: PriceUpdatePayload) { + // Check for liquidation opportunities + // Update collateral requirements + // Trigger rebalancing if needed + } + } + ``` + +2. **Subscribe to oracle**: + ```rust + let oracle = PriceOracleClient::new(&env, &oracle_address); + oracle.subscribe_to_price_updates(&my_contract_address)?; + ``` + +3. **Receive automatic updates**: + ``` + When price changes → Oracle calls on_price_update() → React immediately + ``` + +### For DEX Developers + +1. **Implement callback**: + ```rust + pub fn on_price_update(env: Env, payload: PriceUpdatePayload) { + // Rebalance liquidity pools + // Check slippage limits + // Adjust fee tiers + // Emit events for off-chain systems + } + ``` + +2. **Subscribe**: + ```rust + oracle.subscribe_to_price_updates(&dex_contract)?; + ``` + +## Testing + +### Included Tests + +The implementation includes 11 comprehensive tests: + +1. ✅ `test_subscribe_to_price_updates` - Basic subscription +2. ✅ `test_subscribe_duplicate_fails` - Duplicate prevention +3. ✅ `test_multiple_subscribers` - Multiple registrations +4. ✅ `test_unsubscribe_from_price_updates` - Unsubscribe +5. ✅ `test_unsubscribe_nonexistent_fails` - Error handling +6. ✅ `test_get_empty_subscriber_list` - Empty state +7. ✅ `test_subscribe_unsubscribe_cycle` - Lifecycle +8. ✅ `test_update_price_does_not_crash_with_subscribers` - Integration +9. ✅ `test_set_price_with_subscribers` - Admin integration +10. ✅ `test_subscribe_and_get_subscribers` (callbacks.rs) +11. ✅ `test_unsubscribe` (callbacks.rs) + +Run tests with: +```bash +cd contracts/price-oracle +cargo test +``` + +## Key Features + +### 1. Event-Driven Architecture +- No polling required +- Immediate reaction to price changes +- Real-time synchronization + +### 2. Standardized Interface +- Single `on_price_update` function signature +- All subscribers implement the same contract +- Easy integration for new protocols + +### 3. Gas-Efficient +- O(n) subscription operations (n = subscriber count) +- O(1) callback dispatch per subscriber +- Recommended max: ≤10 subscribers + +### 4. Resilient Design +- Failed callbacks don't block price updates +- Errors logged internally, not propagated +- Non-blocking callback semantics + +### 5. Security +- Oracle is authoritative source +- Subscribers should validate caller +- Price data immutable after callback + +## Usage Examples + +### Example 1: Liquidation Bot (Lending) + +```rust +pub fn on_price_update(env: Env, payload: PriceUpdatePayload) { + let asset = payload.asset; + let new_price = payload.price; + + // Find positions to liquidate + let positions = find_undercollateralized(&env, &asset, new_price); + + for position in positions.iter() { + trigger_liquidation(&env, &position); + } +} +``` + +### Example 2: Pool Rebalancer (DEX) + +```rust +pub fn on_price_update(env: Env, payload: PriceUpdatePayload) { + let old_price = get_last_known_price(&env, &payload.asset); + let price_change_pct = calc_pct_change(old_price, payload.price); + + // Rebalance if price moved >2% + if price_change_pct.abs() > 200 { + rebalance_pool(&env, &payload.asset, payload.price); + } +} +``` + +### Example 3: Price Feed Bridge + +```rust +pub fn on_price_update(env: Env, payload: PriceUpdatePayload) { + // Store price data for other protocols + env.storage().instance().set( + &DataKey::LatestPrice(payload.asset), + &payload + ); + + // Emit event for off-chain indexing + env.events().publish(( + Symbol::new(&env, "oracle_price_update"), + ), ( + payload.asset, + payload.price, + payload.timestamp, + )); +} +``` + +## Error Handling + +### Subscription Errors + +| Error | Cause | Resolution | +|-------|-------|-----------| +| "Contract is already subscribed" | Duplicate subscription | Call unsubscribe first | +| "Contract not found in subscribers" | Unsubscribing non-subscriber | Verify contract is subscribed | + +### Callback Execution + +- Callbacks are best-effort +- Non-blocking: failures don't affect price storage +- Implement defensive validation in `on_price_update` + +```rust +pub fn on_price_update(env: Env, payload: PriceUpdatePayload) { + // Validate data integrity + assert!(payload.price > 0, "Invalid price"); + assert!(payload.timestamp <= env.ledger().timestamp(), "Future timestamp"); + + // Your logic here +} +``` + +## Performance Characteristics + +| Operation | Complexity | Notes | +|-----------|-----------|-------| +| Subscribe | O(n) | n = subscriber count | +| Unsubscribe | O(n) | Linear search + remove | +| Get Subscribers | O(1) | Storage retrieval | +| Callback Dispatch | O(n*m) | n = subscribers, m = callback complexity | +| Price Update | O(1) | Async callback dispatch | + +## Security Considerations + +### For Subscriber Contracts + +1. **Verify Oracle Source**: + ```rust + const ORACLE_ADDRESS: &str = "C..."; + + pub fn on_price_update(env: Env, payload: PriceUpdatePayload) { + assert_eq!(env.invoker(), Address::from_contract_id(&env, ORACLE_ADDRESS)); + } + ``` + +2. **Validate Payload**: + ```rust + // Check timestamp freshness + let now = env.ledger().timestamp(); + assert!(payload.timestamp <= now && payload.timestamp > now - 300); + + // Check price sanity + assert!(payload.price > 0 && payload.price < MAX_REASONABLE_PRICE); + ``` + +3. **Idempotent Updates**: + ```rust + // Design for replayability + // Store both price and update timestamp + // Check if update is newer before applying + ``` + +## Next Steps + +### For Developers + +1. Read [CALLBACK_INTERFACE.md](CALLBACK_INTERFACE.md) for detailed documentation +2. Review test cases in [src/test.rs](contracts/price-oracle/src/test.rs) +3. Implement `on_price_update` in your contract +4. Subscribe to the oracle +5. Test with mock contracts + +### For Integration + +1. Add callback interface to your protocol +2. Update protocol state on `on_price_update` +3. Monitor callback gas usage +4. Set up event listeners for debugging +5. Deploy with ≤10 initial subscribers + +## Support + +- 📖 [Callback Interface Documentation](CALLBACK_INTERFACE.md) +- 🧪 [Test Cases](contracts/price-oracle/src/test.rs) +- 📋 [Integration Guide](contracts/price-oracle/INTEGRATION.md) +- 🤝 [Main README](README.md) + +--- + +**Version**: 1.0.0 +**Status**: ✅ Ready for Production +**Last Updated**: April 25, 2026