[ML] create classes for custom errors

x-pack/plugins/ml/server/shared_services/errors.test.ts

@@ -5,14 +5,44 @@
  * 2.0.
  */
 
-import { getCustomError } from './errors';
+import {
+  getCustomErrorClass,
+  MLClusterClientUninitialized,
+  MLUISettingsClientUninitialized,
+  MLFieldFormatRegistryUninitialized,
+} from './errors';
 
-describe('getCustomError', () => {
+describe('Custom errors', () => {
   test('creates a custom error instance', () => {
-    const error = getCustomError('MLCustomError', 'farequote is not defined');
-    expect(error.message).toBe('farequote is not defined');
-    expect(error.name).toBe('MLCustomError');
+    const MLCustomError = getCustomErrorClass('MLCustomError');
+    const errorInstance = new MLCustomError('farequote is not defined');
+    expect(errorInstance.message).toBe('farequote is not defined');
+    expect(errorInstance.name).toBe('MLCustomError');
+    expect(errorInstance).toBeInstanceOf(MLCustomError);
     // make sure that custom class extends Error
-    expect(error).toBeInstanceOf(Error);
+    expect(errorInstance).toBeInstanceOf(Error);
+  });
+
+  test('MLClusterClientUninitialized', () => {
+    const errorInstance = new MLClusterClientUninitialized('cluster client is not initialized');
+    expect(errorInstance.message).toBe('cluster client is not initialized');
+    expect(errorInstance.name).toBe('MLClusterClientUninitialized');
+    expect(errorInstance).toBeInstanceOf(MLClusterClientUninitialized);
+  });
+
+  test('MLUISettingsClientUninitialized', () => {
+    const errorInstance = new MLUISettingsClientUninitialized('cluster client is not initialized');
+    expect(errorInstance.message).toBe('cluster client is not initialized');
+    expect(errorInstance.name).toBe('MLUISettingsClientUninitialized');
+    expect(errorInstance).toBeInstanceOf(MLUISettingsClientUninitialized);
+  });
+
+  test('MLFieldFormatRegistryUninitialized', () => {
+    const errorInstance = new MLFieldFormatRegistryUninitialized(
+      'cluster client is not initialized'
+    );
+    expect(errorInstance.message).toBe('cluster client is not initialized');
+    expect(errorInstance.name).toBe('MLFieldFormatRegistryUninitialized');
+    expect(errorInstance).toBeInstanceOf(MLFieldFormatRegistryUninitialized);
   });
 });

x-pack/plugins/ml/server/shared_services/errors.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-export const getCustomError = (className: string, errorMessage: string) => {
+export const getCustomErrorClass = (className: string) => {
   const CustomError = class extends Error {
     constructor(message?: string) {
       super(message);
@@ -16,5 +16,15 @@ export const getCustomError = (className: string, errorMessage: string) => {
   };
   // set class name dynamically
   Object.defineProperty(CustomError, 'name', { value: className });
-  return new CustomError(errorMessage);
+  return CustomError;
 };
+
+export const MLClusterClientUninitialized = getCustomErrorClass('MLClusterClientUninitialized');
+
+export const MLUISettingsClientUninitialized = getCustomErrorClass(
+  'MLUISettingsClientUninitialized'
+);
+
+export const MLFieldFormatRegistryUninitialized = getCustomErrorClass(
+  'MLFieldFormatRegistryUninitialized'
+);

x-pack/plugins/ml/server/shared_services/shared_services.ts

@@ -28,7 +28,11 @@ import {
 } from './providers/anomaly_detectors';
 import { ResolveMlCapabilities, MlCapabilitiesKey } from '../../common/types/capabilities';
 import { hasMlCapabilitiesProvider, HasMlCapabilities } from '../lib/capabilities';
-import { getCustomError } from './errors';
+import {
+  MLClusterClientUninitialized,
+  MLFieldFormatRegistryUninitialized,
+  MLUISettingsClientUninitialized,
+} from './errors';
 import { MlClient, getMlClient } from '../lib/ml_client';
 import { jobSavedObjectServiceFactory, JobSavedObjectService } from '../saved_objects';
 import {
@@ -192,18 +196,12 @@ function getRequestItemsProvider(
     );
 
     if (clusterClient === null) {
-      throw getCustomError(
-        'MLClusterClientUninitialized',
-        `ML's cluster client has not been initialized`
-      );
+      throw new MLClusterClientUninitialized(`ML's cluster client has not been initialized`);
     }
 
     const uiSettingsClient = getUiSettings()?.asScopedToClient(savedObjectsClient);
     if (!uiSettingsClient) {
-      throw getCustomError(
-        'MLUISettingsClientUninitialized',
-        `ML's UI settings client has not been initialized`
-      );
+      throw new MLUISettingsClientUninitialized(`ML's UI settings client has not been initialized`);
     }
 
     const getFieldsFormatRegistry = async () => {
@@ -215,8 +213,7 @@ function getRequestItemsProvider(
       }
 
       if (!fieldFormatRegistry) {
-        throw getCustomError(
-          'MLFieldFormatRegistryUninitialized',
+        throw new MLFieldFormatRegistryUninitialized(
           `ML's field format registry has not been initialized`
         );
       }