feat: segregate retry decision for read and write APIs (#1465)

* chore: add tests for retry strategies

* feat: segregate retry decision for read and write APIs

* chore: retry all idempotent operations on cancelled errors

* chore: add comment for why cancelled is retryable

packages/client-sdk-nodejs/src/config/retry/default-eligibility-strategy.ts

@@ -10,7 +10,9 @@ const retryableGrpcStatusCodes: Array<Status> = [
   // commenting out the ones we don't want to retry on for now.
 
   // Status.OK,
-  // Status.CANCELLED,
+  // Idempotent operations can be safely retried for CANCELLED errors. These may pop us sometimes during
+  // client or server side deployments
+  Status.CANCELLED,
   // Status.UNKNOWN,
   // Status.INVALID_ARGUMENT,
   // Status.DEADLINE_EXCEEDED,

packages/client-sdk-nodejs/test/unit/config/retry/default-eligibility-strategy.test.ts

@@ -0,0 +1,108 @@
+import {
+  DefaultEligibilityStrategy,
+  DefaultMomentoLoggerFactory,
+} from '../../../../src';
+import {Status} from '@grpc/grpc-js/build/src/constants';
+import {Metadata, StatusObject} from '@grpc/grpc-js';
+import {ClientMethodDefinition} from '@grpc/grpc-js/build/src/make-client';
+
+describe('DefaultEligibilityStrategy', () => {
+  const testLoggerFactory = new DefaultMomentoLoggerFactory();
+  const eligibilityStrategy = new DefaultEligibilityStrategy(testLoggerFactory);
+
+  it('should return true for INTERNAL status code and GET request path', () => {
+    const grpcStatus = {code: Status.INTERNAL} as StatusObject;
+    const grpcRequest = {
+      path: '/cache_client.Scs/Get',
+    } as ClientMethodDefinition<unknown, unknown>;
+    const requestMetadata = new Metadata();
+
+    const isEligible = eligibilityStrategy.isEligibleForRetry({
+      grpcStatus,
+      grpcRequest,
+      requestMetadata,
+    });
+
+    expect(isEligible).toBe(true);
+  });
+
+  it('should return false for UNKNOWN status code and GET request path', () => {
+    const grpcStatus = {code: Status.UNKNOWN} as StatusObject;
+    const grpcRequest = {
+      path: '/cache_client.Scs/Get',
+    } as ClientMethodDefinition<unknown, unknown>;
+    const requestMetadata = new Metadata();
+
+    const isEligible = eligibilityStrategy.isEligibleForRetry({
+      grpcStatus,
+      grpcRequest,
+      requestMetadata,
+    });
+
+    expect(isEligible).toBe(false);
+  });
+
+  it('should return true for UNAVAILABLE status code and SET request path', () => {
+    const grpcStatus = {code: Status.UNAVAILABLE} as StatusObject;
+    const grpcRequest = {
+      path: '/cache_client.Scs/Set',
+    } as ClientMethodDefinition<unknown, unknown>;
+    const requestMetadata = new Metadata();
+
+    const isEligible = eligibilityStrategy.isEligibleForRetry({
+      grpcStatus,
+      grpcRequest,
+      requestMetadata,
+    });
+
+    expect(isEligible).toBe(true);
+  });
+
+  it('should return true for CANCELLED status code and GET request path', () => {
+    const grpcStatus = {code: Status.CANCELLED} as StatusObject;
+    const grpcRequest = {
+      path: '/cache_client.Scs/Get',
+    } as ClientMethodDefinition<unknown, unknown>;
+    const requestMetadata = new Metadata();
+
+    const isEligible = eligibilityStrategy.isEligibleForRetry({
+      grpcStatus,
+      grpcRequest,
+      requestMetadata,
+    });
+
+    expect(isEligible).toBe(true);
+  });
+
+  it('should return true for CANCELLED status code and SET request path', () => {
+    const grpcStatus = {code: Status.CANCELLED} as StatusObject;
+    const grpcRequest = {
+      path: '/cache_client.Scs/Set',
+    } as ClientMethodDefinition<unknown, unknown>;
+    const requestMetadata = new Metadata();
+
+    const isEligible = eligibilityStrategy.isEligibleForRetry({
+      grpcStatus,
+      grpcRequest,
+      requestMetadata,
+    });
+
+    expect(isEligible).toBe(true);
+  });
+
+  it('should return false for CANCELLED status code and dictionary increment request path', () => {
+    const grpcStatus = {code: Status.CANCELLED} as StatusObject;
+    const grpcRequest = {
+      path: '/cache_client.Scs/DictionaryIncrement',
+    } as ClientMethodDefinition<unknown, unknown>;
+    const requestMetadata = new Metadata();
+
+    const isEligible = eligibilityStrategy.isEligibleForRetry({
+      grpcStatus,
+      grpcRequest,
+      requestMetadata,
+    });
+
+    expect(isEligible).toBe(false);
+  });
+});