VaultWatch - ERC-4626 Deposit Monitor

A lightweight Rust bot that monitors any ERC-4626 vault for deposit availability and sends a Telegram notification when capacity opens up.

How It Works

1. Polls the configured vault contract at a configurable interval (default: 30s).
2. Calls maxDeposit(address) to get the current available deposit capacity.
3. Calls totalAssets() for informational context.
4. If available >= DEPOSIT_THRESHOLD, fires a Telegram alert and logs to console.
5. Alert cooldown: Telegram only fires once per above-threshold window. Resets when available drops below 95% of the threshold (hysteresis, so a vault that oscillates around the threshold does not alert every poll).
6. The cooldown flag is persisted to STATE_FILE (default ./vaultwatch.state) so a restart while the slot is still open does not re-alert.
7. Sends a startup notification to Telegram on launch so you know the bot is online.

Configuration

All configuration is done via environment variables (.env file):

Variable	Required	Description	Example
RPC_URL	yes	Ethereum JSON-RPC endpoint	https://ethereum.publicnode.com
VAULT_ADDRESS	yes	ERC-4626 vault contract address	0x99CD4Ec3f88A45940936F469E4bB72A2A701EEB9
VAULT_NAME	no	Display name for logs (default: ERC-4626 Vault)	stUSDS
TOKEN_DECIMALS	no	Token decimal precision (default: 18)	18
DEPOSIT_THRESHOLD	no	Min available to trigger alert (default: 2000)	2000
POLL_INTERVAL_SECS	no	Seconds between polls (default: 30)	30
TELEGRAM_BOT_TOKEN	no	Telegram Bot API token	123456:ABC-DEF...
TELEGRAM_CHAT_ID	no	Target chat/channel ID	-1001234567890
STATE_FILE	no	Path to the cooldown state file (default: ./vaultwatch.state)	/var/lib/vaultwatch/state.json

Telegram fields are optional. If both are set, the bot sends alerts; otherwise it runs in console-only mode.

Project Structure

src/
  main.rs        -- entry point, wiring only
  config.rs      -- Config struct, env loading, banner
  contract.rs    -- ERC-4626 ABI binding, connect, poll logic
  fmt.rs         -- token formatting, fill percentage, timestamp
  log.rs         -- colored console logging with prefixes
  state.rs       -- on-disk cooldown-flag persistence
  telegram.rs    -- Telegram Bot API (startup + alert messages)

Building and Running

cargo build --release
cargo run --release

Log Prefixes

[*] info      (cyan)
[!] warning   (yellow)
[+] positive  (green)
[-] error     (red)
[?] input     (yellow)

Verbosity is configurable via RUST_LOG (parsed by tracing-subscriber's EnvFilter). Defaults to info.

RUST_LOG=vaultwatch=warn cargo run   # silence the per-poll info line
RUST_LOG=vaultwatch=error cargo run  # only errors
RUST_LOG=vaultwatch=debug cargo run  # extra detail if added later

Tech Stack

Crate	Role
ethers	ERC-4626 contract calls via JSON-RPC
tokio	Single-threaded async runtime + timer
reqwest	Reusable HTTP client for Telegram Bot API
serde	JSON serialization for Telegram payloads
dotenvy	Load .env file at startup
tracing	Structured logging emit
tracing-subscriber	Runtime log filtering (RUST_LOG) + custom format
eyre	Error handling