com_r35157_nenjim-hubd-impl_ref/openspec/changes/archive/2026-08-07-61-add-price-source-sink-architecture/proposal.md

Why

The AssetAZ Ticker currently owns a hardcoded price generator, so acquisition, scheduling, persistence, and publication are coupled in one implementation. Nenjim's future component model constructs components independently and lets a component obtain peer plugins from its context after construction, so price sources must be independently constructible and wired to the ticker only when the ticker starts them.

What Changes

• Add PriceSource and functional PriceSink API contracts in which independently constructed sources receive their sink through start(PriceSink) and own their acquisition resources.
• Keep plugin discovery and lifecycle inside TickerServiceImpl: it obtains PriceSource implementations from its Nenjim context, starts them with itself as sink, and stops them. Ordinary TickerService clients receive no plugin-management API.
• Add the ΩPriceSourceNameΩ ValueTag and include stable source identity in each in-memory PriceObservation.
• BREAKING Replace the single history file with an independent UUID-based history path for each obtained (TradingPair, sourceName) source identity; the old file is not migrated automatically.
• Refactor TickerServiceImpl into a source-agnostic sink that validates callbacks, persists each source independently, and publishes the greatest successfully persisted timestamp across active sources for a pair.
• Move the existing EVE_USDC = 14.85 generation and fixed-delay scheduler into a stoppable HardcodedPriceSource plugin.
• Use a temporary TickerServiceImpl(PriceSource...) Cauldron constructor to simulate the future Nenjim context lookup while constructing HardcodedPriceSource independently.

Capabilities

New Capabilities

None.

Modified Capabilities

• assetaz-ticker-service: Generalize the ticker from one internal generator and history into context-provided source plugins with per-source activation, persistence, lifecycle, and cross-source latest selection.

Impact

• Changes the AssetAZ ticker plugin API and reference implementation under com.r35157.assetaz.core.service.ticker; the ordinary TickerService API exposes lifecycle and price queries, not plugin registration.
• Adds PriceSourceName to the shared Detag hierarchy under String -> Name; this configuration change is explicitly required by issue #61.
• Changes the operator-managed history location and requires manual movement of the old hardcoded history.
• Updates temporary wiring in NenjimHubImpl to construct the source and ticker independently before injecting the source list as a stand-in for future context discovery.
• Adds no Raydium, WebSocket, history-query, retention, or automated-test functionality.