feat(NODE-4847): Add config error handling to logging

src/connection_string.ts

@@ -23,9 +23,11 @@ import {
   ServerApiVersion
 } from './mongo_client';
 import {
+  MongoLoggableComponent,
   MongoLogger,
   type MongoLoggerEnvOptions,
-  type MongoLoggerMongoClientOptions
+  type MongoLoggerMongoClientOptions,
+  SeverityLevel
 } from './mongo_logger';
 import { ReadConcern, type ReadConcernLevel } from './read_concern';
 import { ReadPreference, type ReadPreferenceMode } from './read_preference';
@@ -1246,12 +1248,53 @@ export const OPTIONS = {
    * @internal
    * TODO: NODE-5671 - remove internal flag
    */
-  mongodbLogPath: { type: 'any' },
+  mongodbLogPath: {
+    transform({ values: [value] }) {
+      if (
+        !(
+          (typeof value === 'string' && ['stderr', 'stdout'].includes(value)) ||
+          (value &&
+            typeof value === 'object' &&
+            'write' in value &&
+            typeof value.write === 'function')
+        )
+      ) {
+        throw new MongoAPIError(
+          `Option 'mongodbLogPath' must be of type 'stderr' | 'stdout' | MongoDBLogWritable`
+        );
+      }
+      return value;
+    }
+  },
   /**
    * @internal
    * TODO: NODE-5671 - remove internal flag
    */
-  mongodbLogComponentSeverities: { type: 'any' },
+  mongodbLogComponentSeverities: {
+    transform({ values: [value] }) {
+      if (typeof value !== 'object' || !value) {
+        throw new MongoAPIError(`Option 'mongodbLogComponentSeverities' must be a non-null object`);
+      }
+      for (const [k, v] of Object.entries(value)) {
+        if (typeof v !== 'string' || typeof k !== 'string') {
+          throw new MongoAPIError(
+            `User input for option 'mongodbLogComponentSeverities' object cannot include a non-string key or value`
+          );
+        }
+        if (!Object.values(MongoLoggableComponent).some(val => val === k) && k !== 'default') {
+          throw new MongoAPIError(
+            `User input for option 'mongodbLogComponentSeverities' contains invalid key: ${k}`
+          );
+        }
+        if (!Object.values(SeverityLevel).some(val => val === v)) {
+          throw new MongoAPIError(
+            `Option 'mongodbLogComponentSeverities' does not support ${v} as a value for ${k}`
+          );
+        }
+      }
+      return value;
+    }
+  },
   /**
    * @internal
    * TODO: NODE-5671 - remove internal flag

src/mongo_logger.ts

@@ -281,7 +281,10 @@ export interface Log extends Record<string, any> {
   message?: string;
 }
 
-/** @internal */
+/**
+ * @internal
+ * TODO: NODE-5671 - remove internal flag and add API comments
+ */
 export interface MongoDBLogWritable {
   write(log: Log): PromiseLike<unknown> | unknown;
 }

test/unit/connection_string.test.ts

@@ -912,13 +912,11 @@ describe('Connection String', function () {
     });
 
     context('when option is invalid', function () {
-      it('it defaults to stderr', function () {
-        const client = new MongoClient('mongodb://a/?mongodbLogPath=stdnothing', {
-          [loggerFeatureFlag]: true
-        });
-        const log: Log = { t: new Date(), c: 'ConnectionStringInvalidOption', s: 'error' };
-        client.options.mongoLoggerOptions.logDestination.write(log);
-        expect(stderrStub.write).calledWith(inspect(log, { breakLength: Infinity, compact: true }));
+      it('should throw error at construction', function () {
+        expect(
+          () =>
+            new MongoClient('mongodb://a/?mongodbLogPath=stdnothing', { [loggerFeatureFlag]: true })
+        ).to.throw(MongoAPIError);
       });
     });
   });