feat: retry web3signer connection

yarn-project/node-keystore/src/keystore_manager.test.ts

@@ -1442,7 +1442,7 @@ describe('KeystoreManager', () => {
       expect(validateAccessSpy).toHaveBeenCalledWith(testUrl, [publisherAddress.toString()]);
     });
 
-    it('should handle validation errors', async () => {
+    it('should handle validation errors after retries are exhausted', async () => {
       const testUrl = 'http://test-signer:9000';
       const address = EthAddress.random();
 
@@ -1456,11 +1456,52 @@ describe('KeystoreManager', () => {
         ],
       };
 
+      const manager = new KeystoreManager(keystore);
+
       using validateAccessSpy = jest.spyOn(RemoteSigner, 'validateAccess');
-      validateAccessSpy.mockRejectedValueOnce(new Error('Connection refused'));
+      validateAccessSpy.mockRejectedValue(new Error('Connection refused'));
+
+      jest.useFakeTimers();
+
+      const promise = manager.validateSigners().catch(err => err);
+      await jest.advanceTimersByTimeAsync(32_000);
+      const error = await promise;
+      expect(error).toBeInstanceOf(Error);
+      expect((error as Error).message).toBe('Connection refused');
+
+      jest.useRealTimers();
+    });
+
+    it('should retry and succeed when validateAccess fails transiently', async () => {
+      const testUrl = 'http://test-signer:9000';
+      const address = EthAddress.random();
+
+      const keystore: KeyStore = {
+        schemaVersion: 1,
+        validators: [
+          {
+            attester: { address, remoteSignerUrl: testUrl },
+            feeRecipient: await AztecAddress.random(),
+          },
+        ],
+      };
 
       const manager = new KeystoreManager(keystore);
-      await expect(manager.validateSigners()).rejects.toThrow('Connection refused');
+
+      using validateAccessSpy = jest.spyOn(RemoteSigner, 'validateAccess');
+      validateAccessSpy
+        .mockRejectedValueOnce(new Error('ECONNREFUSED'))
+        .mockRejectedValueOnce(new Error('ECONNREFUSED'))
+        .mockResolvedValueOnce(undefined);
+
+      jest.useFakeTimers();
+
+      const promise = manager.validateSigners();
+      await jest.advanceTimersByTimeAsync(4_000);
+      await expect(promise).resolves.not.toThrow();
+      expect(validateAccessSpy).toHaveBeenCalledTimes(3);
+
+      jest.useRealTimers();
     });
 
     it('should skip validation for mnemonic and JSON V3 configs', async () => {

yarn-project/node-keystore/src/keystore_manager.ts

@@ -7,6 +7,7 @@ import type { EthSigner } from '@aztec/ethereum/eth-signer';
 import { Buffer32 } from '@aztec/foundation/buffer';
 import { EthAddress } from '@aztec/foundation/eth-address';
 import type { Signature } from '@aztec/foundation/eth-signature';
+import { makeBackoff, retry } from '@aztec/foundation/retry';
 import type { AztecAddress } from '@aztec/stdlib/aztec-address';
 
 import { Wallet } from '@ethersproject/wallet';
@@ -61,7 +62,7 @@ export class KeystoreManager {
 
   /**
    * Validates all remote signers in the keystore are accessible and have the required addresses.
-   * Should be called after construction if validation is needed.
+   * Retries each web3signer URL with backoff to tolerate transient unavailability at boot time.
    */
   async validateSigners(): Promise<void> {
     // Collect all remote signers with their addresses grouped by URL
@@ -127,12 +128,18 @@ export class KeystoreManager {
       collectRemoteSigners(this.keystore.prover.publisher, this.keystore.remoteSigner);
     }
 
-    // Validate each remote signer URL with all its addresses
-    for (const [url, addresses] of remoteSignersByUrl.entries()) {
-      if (addresses.size > 0) {
-        await RemoteSigner.validateAccess(url, Array.from(addresses));
-      }
-    }
+    // Validate each remote signer URL with all its addresses, retrying on transient failures
+    await Promise.all(
+      Array.from(remoteSignersByUrl.entries())
+        .filter(([, addresses]) => addresses.size > 0)
+        .map(([url, addresses]) =>
+          retry(
+            () => RemoteSigner.validateAccess(url, Array.from(addresses)),
+            `Validating web3signer at ${url}`,
+            makeBackoff([1, 2, 4, 8, 16]),
+          ),
+        ),
+    );
   }
 
   /**