Merge pull request #1425 from ponmileleke54-dev/#1250

fix: cache Soroban RPC health checks

Author: K1NGD4VID

backend/src/services/sorobanService.ts

@@ -44,6 +44,20 @@ function getTxPollIntervalMs(): number {
   return Number(process.env.SOROBAN_TX_POLL_INTERVAL_MS ?? 1_000);
 }
 
+const DEFAULT_RPC_HEALTH_CACHE_TTL_MS = 10_000;
+
+let rpcHealthCache: { ok: boolean; expiresAt: number } | null = null;
+let rpcHealthPromise: Promise<boolean> | null = null;
+
+function getRpcHealthCacheTtlMs(): number {
+  return Number(process.env.SOROBAN_RPC_HEALTH_CACHE_TTL_MS ?? DEFAULT_RPC_HEALTH_CACHE_TTL_MS);
+}
+
+export function resetRpcHealthCache(): void {
+  rpcHealthCache = null;
+  rpcHealthPromise = null;
+}
+
 export class RpcTimeoutError extends Error {
   constructor(label: string, timeoutMs: number) {
     super(`${label} timed out after ${timeoutMs}ms`);
@@ -139,12 +153,36 @@ async function executeRpc<T>(label: string, operation: (server: rpc.Server) => P
  * unreachable Soroban RPC endpoint can't hang the health check.
  */
 export async function checkRpcHealth(timeoutMs = 3_000): Promise<boolean> {
-  try {
-    await withRpcTimeout('soroban rpc health check', () => executeRpc('soroban rpc health check', (server) => server.getHealth()), timeoutMs);
-    return true;
-  } catch {
-    return false;
+  const now = Date.now();
+  const ttlMs = getRpcHealthCacheTtlMs();
+
+  if (rpcHealthCache && now < rpcHealthCache.expiresAt) {
+    return rpcHealthCache.ok;
   }
+
+  if (rpcHealthPromise) {
+    return rpcHealthPromise;
+  }
+
+  rpcHealthPromise = (async () => {
+    try {
+      const ok = await withRpcTimeout(
+        'soroban rpc health check',
+        () => executeRpc('soroban rpc health check', (server) => server.getHealth()),
+        timeoutMs,
+      );
+      const result = Boolean(ok);
+      rpcHealthCache = { ok: result, expiresAt: Date.now() + ttlMs };
+      return result;
+    } catch {
+      rpcHealthCache = { ok: false, expiresAt: Date.now() + ttlMs };
+      return false;
+    } finally {
+      rpcHealthPromise = null;
+    }
+  })();
+
+  return rpcHealthPromise;
 }
 
 export function setServer(server: rpc.Server): void {

backend/tests/soroban.service.test.ts

@@ -11,6 +11,7 @@ import {
 const mocks = vi.hoisted(() => {
   const server = {
     getAccount: vi.fn(),
+    getHealth: vi.fn(),
     simulateTransaction: vi.fn(),
     sendTransaction: vi.fn(),
     getTransaction: vi.fn(),
@@ -99,6 +100,7 @@ describe('Soroban Service', () => {
   beforeEach(() => {
     vi.clearAllMocks();
     mocks.isSimulationError.mockReturnValue(false);
+    mocks.server.getHealth.mockResolvedValue({ status: 'healthy' });
   });
 
   afterEach(() => {
@@ -107,6 +109,31 @@ describe('Soroban Service', () => {
     delete process.env.SOROBAN_RPC_URL;
   });
 
+  describe('checkRpcHealth', () => {
+    it('caches successful RPC health checks for the TTL window', async () => {
+      const { checkRpcHealth, resetRpcHealthCache } = await importService();
+      resetRpcHealthCache();
+
+      await expect(checkRpcHealth(25)).resolves.toBe(true);
+      await expect(checkRpcHealth(25)).resolves.toBe(true);
+      expect(mocks.server.getHealth).toHaveBeenCalledTimes(1);
+    });
+
+    it('deduplicates concurrent health checks while a refresh is in flight', async () => {
+      const { checkRpcHealth, resetRpcHealthCache } = await importService();
+      resetRpcHealthCache();
+
+      const [first, second] = await Promise.all([
+        checkRpcHealth(25),
+        checkRpcHealth(25),
+      ]);
+
+      expect(first).toBe(true);
+      expect(second).toBe(true);
+      expect(mocks.server.getHealth).toHaveBeenCalledTimes(1);
+    });
+  });
+
   describe('isStale', () => {
     it('should return true if updated more than 30s ago', async () => {
       const { isStale } = await importService();