watcher

DTA Watcher

The DTA watcher is a CRE (Chainlink Runtime Environment) workflow compiled to WASM that monitors DTA smart contract events on-chain. When an event is detected, the handler decodes it, enriches it with on-chain reference data, and posts a signed VerifiableEvent to the CREC API for delivery to users.

Processing Flow

EVM Log (on-chain event)
  │
  ▼
OnLog()                              ─── Main handler entry point
  │
  ├─ BuildEVMEventFromLog()          ─── Decode raw log using contract ABI
  │
  ├─ DTARequestManagement event?
  │    └─ buildReferenceDataFromDTARequestManagementEvent()
  │         ├─ getDistributorRequest()    ─── On-chain read (if request_id present)
  │         └─ getFundToken()             ─── On-chain read (if fund_admin_addr + fund_token_id present)
  │
  ├─ DTASettlementOpened or DTASettlementClosed event?
  │    └─ buildReferenceDataFromDTASettlementEvent()
  │         ├─ getDistributorRequest()    ─── On-chain read
  │         ├─ getFundToken()             ─── On-chain read
  │         ├─ currency code lookup       ─── Off-chain reference data
  │         └─ buildPaymentRequest()      ─── Payment request for settlement
  │
  ├─ BuildVerifiableEventForEVMEvent()  ─── Package into VerifiableEvent
  │
  ▼
SignAndPostVerifiableEvent()            ─── Sign and POST to CREC API

VerifiableEvent Structure

The output VerifiableEvent has this shape:

{
  "name": "SubscriptionRequested",
  "service": "dta.v1",
  "chain_family": "evm",
  "chain_selector": "16015286601757825753",
  "timestamp": "2025-01-15T12:00:00Z",
  "chain_event": {
    "address": "0x...",
    "chain_id": "11155111",
    "tx_hash": "0x...",
    "block_number": 12345678,
    "block_timestamp": 1705305600,
    "event_signature": "SubscriptionRequested(address,bytes32,address,bytes32,uint256,uint40)",
    "topic_hash": "0x...",
    "log_index": 0,
    "params": { ... }
  },
  "data": {
    "type": "reference_data",
    "value": {
      "on_chain": [ ... ],
      "off_chain": [ ... ],
      "requests": [ ... ]
    }
  }
}

The params field contains the decoded Solidity event parameters. The data field contains enrichment data fetched by the handler.

Bundle Schema Fields

Each event in the bundle exposes two JSON Schema fields:

• ParamsSchema — describes chain_event.params (the decoded Solidity event parameters). Auto-generated from the contract ABI by gen/main.go into params_schema_gen.go.
• DataSchema — describes the data enrichment payload (reference data, off-chain lookups, generated requests). Hand-written in bundle.go since it depends on handler logic, not just the ABI. nil for events with no enrichment.

Consumers can use ParamsSchema to decode the event parameters and DataSchema to understand what enrichment data (if any) is attached.

Tip: If you're receiving events from the CREC API as apiClient.Event, the easiest path is to call v1.DecodeFromEvent(ctx, event) which handles all decoding for you — parsing the VerifiableEvent, decoding chain event params into typed Go structs, and extracting enrichment data (FundTokenData, DistributorRequest, PaymentRequests). The schemas here are primarily useful for non-Go consumers or UI rendering.

Supported Events

The watcher monitors events across two DTA contracts. Each event's params schema is documented below.

DTARequestManagement Events

DistributorRegistered

New distributor registered in the DTA system.

Enrichment: None (no request_id or fund_token_id to look up).

DistributorRequestCanceled

A distributor's subscription or redemption request was canceled.

Enrichment: distributor_request (on-chain), fund_token_data (on-chain).

DistributorRequestProcessed

A distributor's request has been fully processed with a result.

Enrichment: distributor_request (on-chain), fund_token_data (on-chain).

DistributorRequestProcessing

A distributor's request is being actively processed.

Enrichment: distributor_request (on-chain), fund_token_data (on-chain).

FundAdminRegistered

A new fund administrator was registered.

Enrichment: None.

FundTokenAllowlistUpdated

A distributor's allowlist status for a fund token was changed.

Enrichment: fund_token_data (on-chain).

FundTokenRegistered

A new fund token was created and registered.

Enrichment: fund_token_data (on-chain).

RedemptionRequested

An investor requested to redeem shares.

Enrichment: distributor_request (on-chain), fund_token_data (on-chain).

SubscriptionRequested

An investor requested to subscribe to a fund.

Enrichment: distributor_request (on-chain), fund_token_data (on-chain).

DTARequestSettlement Events

DTASettlementOpened

A settlement was initiated for a subscription or redemption.

Enrichment: distributor_request (on-chain), fund_token_data (on-chain), currency code (off-chain), payment_request (generated).

DTASettlementClosed

A settlement completed or failed.

Enrichment: distributor_request (on-chain), fund_token_data (on-chain), currency code (off-chain). Reuses the same settlement enrichment pipeline as DTASettlementOpened, minus the payment request.

Reference Data (Enrichment)

For events that have a request_id, fund_admin_addr, or fund_token_id, the handler enriches the event with on-chain data by calling view functions on the DTA contracts.

DistributorRequest

Fetched via DTARequestManagement.getDistributorRequest(bytes32 requestId).

FundTokenData

Fetched via DTARequestManagement.getFundToken(address fundAdmin, bytes32 fundTokenId).

Returns an enabled boolean and a FundTokenData struct containing token configuration, NAV feed details, payment info, and chain selectors.

PaymentRequest (DTASettlementOpened only)

Generated for settlement events to facilitate off-chain payment processing.

Solidity → JSON Type Mapping

The handler decodes Solidity types to JSON values using these conventions: