nautechsystems/nautilus_trader · error · anyhow::Error

DEX ' ' on chain ' ' cannot be synced: missing a…

Error message

DEX '{dex_type}' on chain '{}' cannot be synced: missing a PoolCreated parser for pool discovery.

What it means

`run_sync_dex` syncs a DEX's pools by replaying PoolCreated events. Before starting, it checks `supports_pool_discovery()` on the registered DEX; if no PoolCreated parser is implemented for that DEX/chain, pool discovery is impossible and the sync is aborted with this bail instead of silently producing zero pools.

Solutions

  1. Implement the PoolCreated parser for the DEX and register it so `supports_pool_discovery()` returns true
  2. Choose a different `--dex` value that already supports pool discovery
  3. Seed pools for that DEX by another means (manual registration/import) instead of event-based sync
  4. Verify the dex_type string matches a fully implemented integration

Example fix

// before
// no PoolCreated parser registered for DexKind::MyDex
// after
impl PoolCreatedParser for MyDexParser { /* decode PoolCreated event */ }
registry.register_parser(DexKind::MyDex, MyDexParser);
Defensive patterns

Strategy: validation

Validate before calling

if !dex_extended.supports_pool_discovery() {
    eprintln!("DEX {:?} has no PoolCreated parser; choose another DEX or implement the parser", dex_type);
}

Try / catch

match run_sync_dex(&chain, dex_type).await {
    Err(e) if e.to_string().contains("PoolCreated") => eprintln!("sync unsupported for this DEX: {e}"),
    other => other?,
}

Prevention

When it happens

Trigger: Calling `blockchain sync` (or `run_sync_dex` via `run_blockchain_command`) for a DEX type that is registered on the chain but lacks a PoolCreated event parser implementation.

Common situations: Adding a new DEX integration before implementing its discovery parser; typo'd or newly-added `dex_type` value mapped to a stub; a chain config that registers an unsupported DEX variant.

Related errors

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/8c1537c33006d205. Report an issue: GitHub.

Appendix: source

Thrown at crates/cli/src/blockchain/sync.rs:60

        let supported_dexes = get_supported_dexes_for_chain(chain.name);
        if supported_dexes.is_empty() {
            anyhow::anyhow!("Invalid DEX name '{}' (case-insensitive). Chain '{}' is not supported for pool syncing.",dex, chain.name)
        } else {
            anyhow::anyhow!("Invalid DEX name '{}' (case-insensitive). Supported DEXes for chain '{}': {}",dex,chain.name,supported_dexes.join(", "))
        }
    })?;

    // Fail before connecting to the RPC/database when the DEX cannot discover pools from
    // PoolCreated logs; without a parser sync-dex would otherwise find zero pools silently.
    let dex_extended = get_dex_extended(chain.name, &dex_type).ok_or_else(|| {
        anyhow::anyhow!(
            "DEX '{dex_type}' is not registered on chain '{}'",
            chain.name
        )
    })?;

    if !dex_extended.supports_pool_discovery() {
        anyhow::bail!(
            "DEX '{dex_type}' on chain '{}' cannot be synced: missing a PoolCreated parser for pool discovery.",
            chain.name
        );
    }

    let postgres_connect_options = get_postgres_connect_options(
        database.host,
        database.port,
        database.username,
        database.password,
        database.database,
    );
    // Get RPC HTTP URL: CLI arg, Infura provider, OR RPC_HTTP_URL env var
    let rpc_http_url = rpc_url
        .or_else(|| check_infura_rpc_provider(&chain.name))
        .or_else(|| std::env::var("RPC_HTTP_URL").ok())
        .ok_or_else(|| {
            anyhow::anyhow!(

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