chore: clarify limit exceeded in resource exhausted errors (#1448)

* chore: clarify limit exceeded in resource exhausted errors

* revise error mapping to pass err metadata value, add enum for limit exceeded message wrapper variations

* add extra null check before calling toString

* add extra test to large-messages.test.ts

packages/client-sdk-nodejs/src/errors/cache-service-error-mapper.ts

@@ -116,8 +116,10 @@ export class CacheServiceErrorMapper
         return new TimeoutError(...errParams);
       case Status.UNAUTHENTICATED:
         return new AuthenticationError(...errParams);
-      case Status.RESOURCE_EXHAUSTED:
-        return new LimitExceededError(...errParams);
+      case Status.RESOURCE_EXHAUSTED: {
+        const errCause = errParams[2]?.get('err')?.[0]?.toString();
+        return new LimitExceededError(...errParams, errCause);
+      }
       case Status.ALREADY_EXISTS: {
         let errCause = errParams[2]?.get('err')?.[0];
         // TODO: Remove this once the error message is standardized on the server side

packages/client-sdk-nodejs/test/integration/cache/large-messages.test.ts

@@ -43,4 +43,22 @@ describe('CacheClient', () => {
       expect(responseValue).toEqual(value);
     }, `expected 5mb retrieved string to match 5mb value that was set for key ${key}`);
   });
+
+  it('should fail with RESOURCE_EXHAUSTED_ERROR when setting a value greater than 5mb', async () => {
+    const cacheKey = v4();
+    const cacheValue = 'x'.repeat(5_300_000);
+    const setResponse = await cacheClient.set(
+      integrationTestCacheName,
+      cacheKey,
+      cacheValue
+    );
+    const stringifiedSetResponse = setResponse.toString();
+    expectWithMessage(() => {
+      expect(setResponse).toBeInstanceOf(CacheSet.Error);
+    }, `expected ERROR but got ${stringifiedSetResponse}`);
+    expect(stringifiedSetResponse).toInclude('RESOURCE_EXHAUSTED');
+    expect(stringifiedSetResponse).toInclude(
+      'Request size limit exceeded for this account'
+    );
+  });
 });

packages/client-sdk-web/src/errors/cache-service-error-mapper.ts

@@ -112,8 +112,11 @@ export class CacheServiceErrorMapper
         return new TimeoutError(...errParams);
       case StatusCode.UNAUTHENTICATED:
         return new AuthenticationError(...errParams);
-      case StatusCode.RESOURCE_EXHAUSTED:
-        return new LimitExceededError(...errParams);
+      case StatusCode.RESOURCE_EXHAUSTED: {
+        const meta = errParams[2] ?? {};
+        const errCause = meta['err'];
+        return new LimitExceededError(...errParams, errCause);
+      }
       case StatusCode.ALREADY_EXISTS: {
         let errCause = '';
         // TODO: Remove this once the error message is standardized on the server side

packages/core/src/errors/errors.ts

@@ -66,7 +66,7 @@ export class MomentoErrorTransportDetails {
 export abstract class SdkError extends Error {
   protected readonly _errorCode: MomentoErrorCode;
   protected readonly _messageWrapper: string;
-  private readonly _transportDetails: MomentoErrorTransportDetails;
+  protected readonly _transportDetails: MomentoErrorTransportDetails;
   constructor(
     message: string,
     code = 0,
@@ -174,13 +174,79 @@ export class InvalidArgumentError extends SdkError {
   override _messageWrapper = 'Invalid argument passed to Momento client';
 }
 
+enum LimitExceededMessageWrapper {
+  TOPIC_SUBSCRIPTIONS_LIMIT_EXCEEDED = 'Topic subscriptions limit exceeded for this account',
+  OPERATIONS_RATE_LIMIT_EXCEEDED = 'Request rate limit exceeded for this account',
+  THROUGHPUT_RATE_LIMIT_EXCEEDED = 'Bandwidth limit exceeded for this account',
+  REQUEST_SIZE_LIMIT_EXCEEDED = 'Request size limit exceeded for this account',
+  ITEM_SIZE_LIMIT_EXCEEDED = 'Item size limit exceeded for this account',
+  ELEMENT_SIZE_LIMIT_EXCEEDED = 'Element size limit exceeded for this account',
+  UNKNOWN_LIMIT_EXCEEDED = 'Limit exceeded for this account',
+}
+
 /**
  * Error when calls are throttled due to request limit rate
  */
 export class LimitExceededError extends SdkError {
   override _errorCode = MomentoErrorCode.LIMIT_EXCEEDED_ERROR;
-  override _messageWrapper =
-    'Request rate, bandwidth, or object size exceeded the limits for this account.  To resolve this error, reduce your usage as appropriate or contact us at [email protected] to request a limit increase';
+  override _messageWrapper = this.determineMessageWrapper();
+  private errCause: string | undefined;
+
+  constructor(
+    message: string,
+    code = 0,
+    metadata: object | undefined = undefined,
+    stack: string | undefined = undefined,
+    errCause?: string
+  ) {
+    super(message, code, metadata, stack);
+    this.errCause = errCause;
+  }
+
+  private determineMessageWrapper() {
+    // If provided, we use the `err` metadata value to determine the most
+    // appropriate error message to return.
+    if (this.errCause !== undefined) {
+      switch (this.errCause) {
+        case 'topic_subscriptions_limit_exceeded':
+          return LimitExceededMessageWrapper.TOPIC_SUBSCRIPTIONS_LIMIT_EXCEEDED;
+        case 'operations_rate_limit_exceeded':
+          return LimitExceededMessageWrapper.OPERATIONS_RATE_LIMIT_EXCEEDED;
+        case 'throughput_rate_limit_exceeded':
+          return LimitExceededMessageWrapper.THROUGHPUT_RATE_LIMIT_EXCEEDED;
+        case 'request_size_limit_exceeded':
+          return LimitExceededMessageWrapper.REQUEST_SIZE_LIMIT_EXCEEDED;
+        case 'item_size_limit_exceeded':
+          return LimitExceededMessageWrapper.ITEM_SIZE_LIMIT_EXCEEDED;
+        case 'element_size_limit_exceeded':
+          return LimitExceededMessageWrapper.ELEMENT_SIZE_LIMIT_EXCEEDED;
+        default:
+          return LimitExceededMessageWrapper.UNKNOWN_LIMIT_EXCEEDED;
+      }
+    }
+
+    // If `err` metadata is unavailable, try to use the error details field
+    // to return the an appropriate error message.
+    if (this._transportDetails.grpc.details !== undefined) {
+      const details = this._transportDetails.grpc.details.toLowerCase();
+      if (details.includes('subscribers')) {
+        return LimitExceededMessageWrapper.TOPIC_SUBSCRIPTIONS_LIMIT_EXCEEDED;
+      } else if (details.includes('operations')) {
+        return LimitExceededMessageWrapper.OPERATIONS_RATE_LIMIT_EXCEEDED;
+      } else if (details.includes('throughput')) {
+        return LimitExceededMessageWrapper.THROUGHPUT_RATE_LIMIT_EXCEEDED;
+      } else if (details.includes('request limit')) {
+        return LimitExceededMessageWrapper.REQUEST_SIZE_LIMIT_EXCEEDED;
+      } else if (details.includes('item size')) {
+        return LimitExceededMessageWrapper.ITEM_SIZE_LIMIT_EXCEEDED;
+      } else if (details.includes('element size')) {
+        return LimitExceededMessageWrapper.ELEMENT_SIZE_LIMIT_EXCEEDED;
+      }
+    }
+
+    // If all else fails, return a generic "limit exceeded" message
+    return LimitExceededMessageWrapper.UNKNOWN_LIMIT_EXCEEDED;
+  }
 }
 
 /**