Feature: Add Oracle provider failover with priority ordering #79
Description
Problem
When a price provider fails, the Oracle aggregator treats all providers equally. There's no way to prioritize certain providers over others for failover.
Context
Some providers (e.g., Binance) may be more reliable or have lower latency. Prioritization ensures the best data source is used when available.
Proposed Solution
Add priority-based failover:
interface ProviderConfig {
priority: number; // 1 = highest
name: string;
enabled: boolean;
// ...
}Providers tried in priority order; lower-priority providers used only when higher-priority ones fail.
Acceptance Criteria
- Providers ordered by priority
- Higher-priority provider preferred when available
- Automatic failover to lower priority on failure
- Recovery: switch back to higher priority when it recovers
- Tests for failover and recovery
Technical Notes
- Files:
oracle/src/services/price-aggregator.ts,oracle/src/config.ts
Constraints
- Must not increase latency when primary provider is healthy