{"record":{"id":"e4e984310ebc0c96","repo":"nautechsystems/nautilus_trader","slug":"no-order-book-returned-from-okx","errorCode":null,"errorMessage":"No order book returned from OKX","messagePattern":"No order book returned from OKX","errorType":"exception","errorClass":"anyhow::Error","httpStatus":null,"severity":"error","filePath":"crates/adapters/okx/src/http/client.rs","lineNumber":2912,"sourceCode":"    ) -> anyhow::Result<OrderBook> {\n        let inst = self.instrument_from_cache_by_id(instrument_id)?;\n        let price_precision = inst.price_precision();\n        let size_precision = inst.size_precision();\n\n        let params = GetOrderBookParams {\n            inst_id: instrument_id.symbol.to_string(),\n            sz: depth,\n        };\n\n        let resp = self\n            .inner\n            .get_order_book(params)\n            .await\n            .map_err(|e| anyhow::anyhow!(e))?;\n\n        let snapshot = resp\n            .first()\n            .ok_or_else(|| anyhow::anyhow!(\"No order book returned from OKX\"))?;\n\n        let ts_event = UnixNanos::from(snapshot.ts * NANOSECONDS_IN_MILLISECOND);\n        let mut book = OrderBook::new(instrument_id, BookType::L2_MBP);\n\n        for (i, level) in snapshot.bids.iter().enumerate() {\n            let price = parse_price(&level.0, price_precision)?;\n            let size = parse_quantity(&level.1, size_precision)?;\n            let order = BookOrder::new(OrderSide::Buy, price, size, i as u64);\n            book.add(order, 0, i as u64, ts_event);\n        }\n\n        let bids_len = snapshot.bids.len();\n\n        for (i, level) in snapshot.asks.iter().enumerate() {\n            let price = parse_price(&level.0, price_precision)?;\n            let size = parse_quantity(&level.1, size_precision)?;\n            let order = BookOrder::new(OrderSide::Sell, price, size, (bids_len + i) as u64);\n            book.add(order, 0, (bids_len + i) as u64, ts_event);","sourceCodeStart":2894,"sourceCodeEnd":2930,"githubUrl":"https://github.com/nautechsystems/nautilus_trader/blob/18893faf8b356be3320add8de2f861b0b647cf06/crates/adapters/okx/src/http/client.rs#L2894-L2930","documentation":"Response guard in the OKX HTTP client's order book fetch: the API returned an empty list of books, so no snapshot exists for the requested instrument/depth and the call fails instead of returning an empty book.","triggerScenarios":"OKX responds with data: [] for get_order_book — typically an unknown/delisted instId or a race where the instrument was just suspended/delisted mid-request.","commonSituations":"Requesting a snapshot for an instrument removed from OKX, a typo'd or mis-derived inst_id, or exchange-side data gaps during incidents/maintenance.","solutions":["Confirm the inst_id exists via /api/v5/public/instruments before requesting the book.","Re-sync the instrument cache if the instrument may have been delisted.","Treat empty responses as a skip-and-retry condition rather than a fatal error.","Check OKX system status for ongoing incidents."],"exampleFix":"// before\nlet snapshot = resp.first().ok_or_else(|| anyhow::anyhow!(\"No order book returned from OKX\"))?;\n// after\nlet Some(snapshot) = resp.first() else {\n    tracing::warn!(\"OKX book snapshot empty for {instrument_id}; will retry\");\n    return Err(anyhow::anyhow!(\"empty order book response\"));\n};","handlingStrategy":"fallback","validationCode":"if !okx_instruments_live.contains(inst_id.as_str()) {\n    return Err(anyhow::anyhow!(\"instrument {inst_id} not live on OKX\"));\n}","typeGuard":null,"tryCatchPattern":"let Some(snapshot) = resp.first() else {\n    tracing::warn!(\"empty OKX book for {instrument_id}\");\n    return Err(anyhow::anyhow!(\"empty book response; retry later\"));\n};","preventionTips":["Re-check the instrument cache for delisted instruments on this error.","Retry the initial snapshot once before giving up.","Monitor OKX system status for data gaps."],"tags":["okx","orderbook","empty-response","exchange-api"],"backgroundTag":"empty-result-set","analyzedSha":"18893faf8b356be3320add8de2f861b0b647cf06","analyzedAt":"2026-09-08T20:49:34.690Z","contentChangedAt":"2026-09-08T20:49:34.690Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}