fix: simplify alert provider load logic (#1220)

Dynamic module resolution causes issues in builds that use tools like esbuild; resulting paths are often not the same as they would in the source tree. Instead we can simplify the loading logic to use a defined object map of names to constructor functions. The mapping object should be small enough that merge conflicts with forks should be easy to resolve.

Author: dhable

packages/api/src/tasks/__tests__/checkAlertsTask.test.ts

@@ -20,7 +20,6 @@ import { CheckAlertsTaskArgs } from '../types';
 jest.mock('@/tasks/providers', () => {
   return {
     ...jest.requireActual('@/tasks/providers'),
-    isValidProvider: jest.fn().mockReturnValue(true),
     loadProvider: jest.fn(),
   };
 });

packages/api/src/tasks/providers/__tests__/index.test.ts

@@ -1,5 +1,6 @@
 import { ClickhouseClient } from '@hyperdx/common-utils/dist/clickhouse/node';
 import { Tile } from '@hyperdx/common-utils/dist/types';
+import _ from 'lodash';
 
 import { ObjectId } from '@/models';
 import { IAlert } from '@/models/alert';
@@ -83,48 +84,26 @@ export interface AlertProvider {
   getClickHouseClient(connection: IConnection): Promise<ClickhouseClient>;
 }
 
-export function isValidProvider(obj: any): obj is AlertProvider {
-  return (
-    obj != null &&
-    typeof obj.init === 'function' &&
-    typeof obj.asyncDispose === 'function' &&
-    typeof obj.getAlertTasks === 'function' &&
-    typeof obj.buildLogSearchLink === 'function' &&
-    typeof obj.buildChartLink === 'function' &&
-    typeof obj.updateAlertState === 'function' &&
-    typeof obj.getWebhooks === 'function' &&
-    typeof obj.getClickHouseClient === 'function'
-  );
-}
+const ADDITIONAL_PROVIDERS: Record<string, () => AlertProvider> = {
+  // Additional alert provider create functions should appear in this object
+  // defined with a provider name.
+};
 
 export async function loadProvider(
   providerName?: string | undefined | null,
 ): Promise<AlertProvider> {
   if (providerName && providerName !== 'default') {
-    try {
-      const ProviderClass = (await import(`./${providerName}`)).default;
-      if (typeof ProviderClass === 'function') {
-        const providerInstance = new ProviderClass();
-        if (isValidProvider(providerInstance)) {
-          return providerInstance;
-        } else {
-          logger.warn({
-            message: `"${providerName}" does not implement AlertProvider`,
-            providerName,
-          });
-        }
-      } else {
-        logger.warn({
-          message: `"${providerName}" does not export default constructor`,
+    const providerFn = _.get(ADDITIONAL_PROVIDERS, providerName);
+    if (providerFn) {
+      try {
+        return providerFn();
+      } catch (err) {
+        logger.error({
+          message: `error creating instance of ${providerName} provider; using default`,
+          cause: err,
           providerName,
         });
       }
-    } catch (e) {
-      logger.warn({
-        message: `failed to load "${providerName}: ${e}"`,
-        cause: e,
-        providerName,
-      });
     }
   }