- Fix framework references (actix-web, not hyper) - Update all env var names (BAL_SERVER_*/BAL_PUSHER_* prefix) - Add validation.rs module documentation - Fix function signatures in xpub.rs and db.rs - Update API response formats (InfoResponse, StatsResponse) - Fix database schema (date_creation/date_update, push_err, tbl_stats) - Mark fixed vulnerabilities with current status - Add Docker support and actix tuning documentation - Remove outdated references (confy, bal-stats.rs.dontcompile) - Add regression test summary table
70 lines
3.6 KiB
Markdown
70 lines
3.6 KiB
Markdown
# Architecture and Data Flow
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## Quick Reference
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- **What this file contains:** high-level architecture, data flow, state machine, and error handling strategy.
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- **See also:** [01_project_overview.md](01_project_overview.md), [04_modules_detail.md](04_modules_detail.md), [05_api_reference.md](05_api_reference.md), [06_database_schema.md](06_database_schema.md)
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## High-Level Architecture
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```
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User
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| HTTP POST (raw hex transactions)
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v
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+-----------------+
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| bal-server | (actix-web 4.9.0 + actix-governor, async)
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| (src/bin/bal-server.rs) |
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+-----------------+
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| SQLite insert (db.rs, Arc<Mutex<Connection>>)
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v
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bal.db (WAL mode)
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| (transactions with status=0, waiting locktime)
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| ZMQ (hashblock)
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v
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+-----------------+
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| bal-pusher | (tokio, ZMQ + RPC + reqwest)
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| (src/bin/bal-pusher.rs)
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+-----------------+
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| bitcoincore-rpc
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| sendrawtransaction
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Bitcoin Network
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```
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## Data Flow (Transaction Lifecycle)
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1. **Submission**: A client sends one or more raw hex transactions to the `pushtxs` endpoint (newline-separated).
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2. **Validation**: The `bal-server` parses each transaction using `bitcoin::Transaction` via `consensus::deserialize`. It checks for the fee output, extracts inputs/outputs, and validates the locktime.
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3. **Storage**: Valid transactions are stored in `tbl_tx` with `status = 0` (waiting). The inputs and outputs are stored in `tbl_inp` and `tbl_out`. Batch inserts use `UNION ALL SELECT` for efficiency.
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4. **Monitoring**: The `bal-pusher` listens to the ZMQ `hashblock` topic with a 5-second receive timeout. When a new block is detected, it fetches blockchain info via RPC.
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5. **Evaluation**: The pusher queries the database for transactions with `status=0` and compares their locktime against the blockchain's best block height or median time (for timestamp-based locktimes above `LOCKTIME_THRESHOLD`).
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6. **Broadcast**: If the locktime is satisfied, the pusher sends the transaction via `sendrawtransaction` and updates the status to `1` (sent) or `2` (failed with error stored in `push_err`).
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7. **Statistics**: The pusher periodically calculates statistics and sends them to a remote `welist` server using an Ed25519-signed POST request. The server also exposes stats via the `GET /:network/stats` endpoint if `expose_stats` is enabled.
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## State Machine
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```
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[Submitted] -> status=0 (waiting)
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| locktime satisfied
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v
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[Push attempt] -> status=1 (sent) or status=2 (failed)
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```
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The `status` field in `tbl_tx` is an integer:
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- `0`: Waiting for locktime.
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- `1`: Successfully sent to the network.
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- `2`: Failed (e.g., RPC error `-25 bad-txns-inputs-missingorspent`). Error details stored in `push_err`.
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## Error Handling Strategy
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The codebase has been hardened with comprehensive error handling:
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- **`bal-server`**: Uses `actix-web`'s built-in error handling. All `unwrap()`/`expect()` calls have been replaced with safe `match`/`if let` error propagation, returning appropriate HTTP status codes (400, 404, 500).
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- **`bal-pusher`**: ZMQ `recv` uses `set_rcvtimeo(5000)` with a match/timeout handler. RPC connection failures log errors and retry with a sleep interval instead of panicking. The pusher logs warnings for consecutive ZMQ timeouts (~1 hour threshold).
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- **`db.rs`**: Database operations use `Result` types. The `open_db` function validates paths before opening. WAL mode is set with retry logic.
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## Logging and Monitoring
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The project uses `env_logger` and `log`. By default, `RUST_LOG=info` is set. The `bal-pusher` sends signed statistics to a remote server. The server exposes a `stats` endpoint (`/<network>/stats`) if `expose_stats` is enabled. The actix-web `Logger::default()` middleware logs all HTTP requests/responses.
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