fix(trust-graph): count discovery 5xx failures

services/trust-graph/src/services/trust-service.ts

@@ -314,16 +314,11 @@ export class TrustService {
           // Reset circuit breaker on success
           this.circuitBreaker.failureCount = 0
         } else if (response.status >= 500) {
-          throw new TrustError(`Discovery service unavailable while resolving identity: ${did}`)
+          this.recordDiscoveryFailure(did)
         }
       } catch (error) {
         if (error instanceof TrustError) throw error
-        // Discovery service unavailable — increment circuit breaker
-        this.circuitBreaker.failureCount++
-        if (this.circuitBreaker.failureCount >= CIRCUIT_BREAKER_THRESHOLD) {
-          this.circuitBreaker.openUntil = Date.now() + CIRCUIT_BREAKER_RESET_MS
-        }
-        throw new TrustError(`Discovery service unavailable while resolving identity: ${did}`)
+        this.recordDiscoveryFailure(did)
       }
 
       if (!identity || !identity.publicKey) {
@@ -517,6 +512,14 @@ export class TrustService {
 
     return new Uint8Array(publicKey)
   }
+
+  private recordDiscoveryFailure(did: string): never {
+    this.circuitBreaker.failureCount++
+    if (this.circuitBreaker.failureCount >= CIRCUIT_BREAKER_THRESHOLD) {
+      this.circuitBreaker.openUntil = Date.now() + CIRCUIT_BREAKER_RESET_MS
+    }
+    throw new TrustError(`Discovery service unavailable while resolving identity: ${did}`)
+  }
 }
 
 function isRevocationRecord(record: unknown): record is RevocationRecord {

services/trust-graph/test/trust-service.test.ts

@@ -1,4 +1,4 @@
-import { describe, it, expect, beforeEach, vi } from 'vitest'
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest'
 import { TrustService } from '../src/services/trust-service.js'
 import type { CreateTrustRequest } from '../src/types.js'
 import {
@@ -39,6 +39,10 @@ describe('TrustService', () => {
     }
   })
 
+  afterEach(() => {
+    vi.unstubAllGlobals()
+  })
+
   function mockIdentity(publicKey: Uint8Array) {
     mockDb.select = vi.fn(() => ({
       from: vi.fn(() => ({
@@ -212,6 +216,25 @@ describe('TrustService', () => {
   })
 
   describe('getScore', () => {
+    it('opens the discovery circuit breaker after repeated 5xx responses', async () => {
+      service = new TrustService('http://discovery.test')
+      const fetchMock = vi.fn(() => Promise.resolve(new Response('unavailable', { status: 503 })))
+      vi.stubGlobal('fetch', fetchMock)
+
+      for (let attempt = 0; attempt < 5; attempt++) {
+        await expect(service.getScore(mockDb, `did:fides:missing-${attempt}`)).rejects.toThrow(
+          'Discovery service unavailable'
+        )
+      }
+
+      expect(fetchMock).toHaveBeenCalledTimes(5)
+
+      await expect(service.getScore(mockDb, 'did:fides:circuit-open')).rejects.toThrow(
+        'Discovery service unavailable'
+      )
+      expect(fetchMock).toHaveBeenCalledTimes(5)
+    })
+
     it('should return cached score if valid', async () => {
       const now = new Date()
       const recentCompute = new Date(now.getTime() - 1800000) // 30 min ago