feat(protocols): Venus adapter (charon-protocols crate, closes #9)#33
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feat(protocols): Venus adapter (charon-protocols crate, closes #9)#33
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…ub (#8) First commit in the #8 series. Lays out the crate layout so subsequent commits can land ABIs, RPC wiring, and the LendingProtocol impl without simultaneously introducing new module boundaries. - New `charon-protocols` workspace member with a single `venus` module - `VenusAdapter` is a minimal struct holding the Comptroller address; provider, vToken discovery, and trait impl land in follow-ups - No scanner/executor consumption yet — zero behaviour change for existing commands (`listen`, `test-connection`)
#8) Second commit in the #8 series. Defines typed RPC bindings for every Venus method the scanner and executor need, using alloy's `sol!` macro with `#[sol(rpc)]` so each interface gets a `new(address, provider)` constructor and per-method decoding for free. - `IVenusComptroller`: getAccountLiquidity, getAssetsIn, getAllMarkets, closeFactorMantissa, liquidationIncentiveMantissa, oracle - `IVToken`: underlying, balanceOf, borrowBalanceStored/Current, balanceOfUnderlying, exchangeRateStored, decimals, symbol, liquidateBorrow - `IVenusOracle`: getUnderlyingPrice (Compound-style scaling) Still no runtime logic — bindings only. VenusAdapter continues to be a scaffold struct; the LendingProtocol impl lands next commit.
Third commit in the #8 series. Wires the adapter to a shared pub-sub provider and caches Venus's rarely-changing market config at connect time, so per-block calls don't re-hit the Comptroller for invariants. - `VenusAdapter::connect(provider, comptroller)` fetches the oracle address, vToken market list, and close factor via three read-only RPCs; stores them on the struct - Shared provider held as `Arc<RootProvider<PubSubFrontend>>` so the scanner can hand the same provider to multiple adapters cheaply - Live integration test (`tests/venus_connect.rs`) hits BSC mainnet when `BNB_WS_URL` is set, skipped otherwise — proves the Comptroller roundtrip works end to end Venus's Diamond Comptroller does not expose `liquidationIncentiveMantissa()` globally (per-market in Diamond facets); that lookup is deferred to the liquidation builder in a later commit rather than bundled into `connect`.
Fourth commit in the #8 series. Implements on-chain position discovery for Venus — the core translation that turns Compound V2's `(errorCode, liquidity, shortfall)` + per-vToken balances into the shared `Position` shape the scanner consumes. - `VenusAdapter::connect` now also resolves every vToken's `underlying()` address and caches both directions of the map; vBNB-style native-wrapping markets (no `underlying()`) are skipped with a debug log and left unmapped - Adapter tracks its own `chain_id` via `eth_chainId` for position metadata - `fetch_position_inner` walks `getAssetsIn`, reads per-vToken `borrowBalanceStored` + `balanceOfUnderlying` + oracle price, and picks the single biggest-value debt vToken and biggest-value collateral vToken as the Position to report - Per-asset failures (oracle revert, missing market) are logged and skipped so one broken market can't blank an entire borrower - Health factor synthesised as a binary 0 / 2e18 signal from Venus's `shortfall`: enough for the scanner's `< 1e18` predicate, precise HF arithmetic deferred to the 3-bucket scanner (#9) - `LendingProtocol::get_liquidation_params` and `build_liquidation_calldata` are stubbed with explicit errors — they land in the next commit alongside per-market liquidation incentive lookup Live integration test (`tests/venus_fetch.rs`) calls `fetch_positions` for a clean address on BSC mainnet, verifying the full pipeline returns well-formed (or empty) results without panicking.
) Fifth commit in the #8 series. Completes the `LendingProtocol` impl on the Rust side — the trait no longer returns `bail!("unimplemented")` and an opportunity can now be turned into ready-to-sign bytes. - `get_liquidation_params` maps underlying ERC-20 debt / collateral addresses on the `Position` back to Venus vToken addresses via the adapter's lookup map, and caps `repay_amount` at `debt_amount × close_factor / 1e18` (50% on BSC Venus). Refuses to emit a zero-repay params struct. - `build_liquidation_calldata` delegates to a free `encode_liquidate_borrow_calldata` helper that encodes `VToken.liquidateBorrow(borrower, repayAmount, vTokenCollateral)` via alloy's generated call struct + `SolCall::abi_encode`. Split as a free function so it can be unit-tested without constructing a full adapter. - Unit test asserts the 4-byte selector matches alloy's `liquidateBorrowCall::SELECTOR` constant and that calldata length is selector + 3 × 32-byte slots — catches any accidental ABI drift (wrong arg order, extra params). The outer wrapping into `CharonLiquidator.executeLiquidation(...)` is intentionally *not* done here; that calldata shape depends on the Solidity contract, which is a separate milestone (M2 Execution). Shipping the inner Venus-specific calldata now unblocks scanner + profit-calc work without waiting on the contract.
Final commit in the #8 series. The adapter built across Parts A–E is now driven by real block events: `charon listen` constructs a `VenusAdapter` at startup and, for every new BSC block from the existing `BlockListener`, runs one `fetch_positions` scan against a caller-supplied borrower list. - `listen --borrower 0x…` flag (repeatable, empty by default) seeds the scan list. Full borrower discovery from indexed `Borrow` events is its own task, tracked under the health-scanner milestone (#9) - Per-block structured log: `venus scan chain=… block=… tracked=… returned=… scan_ms=…` - Adapter and listener use separate WebSocket connections for now; sharing a single pub-sub provider is a cheap optimisation once the scanner owns the full runtime (#9) - `charon-cli` now depends on `charon-protocols` and the alloy primitives crate for address parsing via clap Live soak on BSC: 25 blocks / 25 scans in 30 s, zero warnings, Venus adapter snapshot reports 48 markets with 47 mapped (vBNB skipped, as intended).
This was referenced Apr 22, 2026
…ntive, concurrent borrowers - Replace balanceOfUnderlying (non-view, accrues interest) with balanceOf * exchangeRateStored / 1e18 on the scan path. Works against rate-limited and view-only RPC proxies that reject state-mutating eth_calls. balanceOfUnderlying + borrowBalanceCurrent removed from the ABI entirely to prevent future accidental use. - Real health factor derived from the Comptroller's own liquidity and shortfall values plus the per-block sum of borrow * price: HF = (total_borrow_val +/- liquidity_or_shortfall) / total_borrow_val, 1e18-scaled. Replaces the 0/2e18 binary placeholder so bucket classifiers can rank positions by urgency. - vBNB special case: vBNB (0xA07c…) has no underlying() and used to be silently skipped, invisibling BSC's largest Venus market. connect() now maps vBNB -> Wrapped BNB (0xbb4C…) in both directions so BNB- collateral borrowers are scanned and can be liquidated. - Add liquidationIncentiveMantissa() to the Comptroller ABI, fetch it at connect alongside closeFactorMantissa, and derive liquidation_bonus_bps from the live value at scan time: bps = (mantissa - 1e18) / 1e14. Governance can change the incentive without the bot running on a stale hardcoded 1000 bps. - VenusAdapter fields are now pub(crate) / private, guarded by a tokio RwLock so they can be refreshed atomically. A new refresh() async method re-queries Comptroller state and swaps the snapshot; operators (or a timer/event watcher) call it to pick up governance changes and newly listed markets without restart. markets(), oracle(), close_factor_mantissa(), liquidation_incentive_mantissa() expose read-only accessors. - fetch_positions now processes borrowers concurrently through FuturesUnordered so the scan walltime drops from sequential 50+ borrowers to the slowest single borrower. Follow-up issue should introduce Multicall3 aggregate for per-borrower per-vToken reads. Closes #97 #98 #99 #100 #101 #102
# Conflicts: # crates/charon-cli/src/main.rs
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Closes #9
New
charon-protocolscrate with the Venus adapter — the firstLendingProtocolimplementation. Six-commit series consolidated on squash:VenusAdapterstructunderlying ↔ vTokenmap (vBNB skipped — nounderlying())fetch_positions— walksgetAssetsIn, reads per-vToken borrow + supply + oracle price, picks biggest-value debt + collateral pair, synthesises health factor fromshortfalldebt × close_factor / 1e18(50% on BSC Venus), ABI-encodes innerVToken.liquidateBorrowcalllistenbuilds the adapter at startup; every new block triggers onefetch_positionsscan with--borrower 0x…flag for test seedingLive-verified on BSC: 48 markets, 47 mapped, oracle
0x6592…b8A, close factor 0.5e18. 25 scans / 25 blocks in 30 s with zero warnings.Depends on #8 (
feat/07-block-listener).