start testing

Author: W-A-James

src/mongo_logger.ts

@@ -53,6 +53,8 @@ export const SeverityLevel = Object.freeze({
   OFF: 'off'
 } as const);
 
+/** @internal */
+export const DEFAULT_MAX_DOCUMENT_LENGTH = 1000;
 /** @internal */
 export type SeverityLevel = (typeof SeverityLevel)[keyof typeof SeverityLevel];
 
@@ -253,6 +255,13 @@ export type LoggableEvent =
 export interface LogConvertible extends Record<string, any> {
   toLog(): Record<string, any>;
 }
+export function maybeTruncate(ejson: string, maxDocumentLength: number): string {
+  if (maxDocumentLength === 0) {
+    return ejson;
+  }
+
+  return ejson.length > maxDocumentLength ? `${ejson.slice(0, maxDocumentLength)}...` : ejson;
+}
 
 /** @internal */
 export type Loggable = LoggableEvent | LogConvertible;
@@ -494,7 +503,8 @@ export class MongoLogger {
         default: defaultSeverity
       },
       maxDocumentLength:
-        parseUnsignedInteger(combinedOptions.MONGODB_LOG_MAX_DOCUMENT_LENGTH) ?? 1000,
+        parseUnsignedInteger(combinedOptions.MONGODB_LOG_MAX_DOCUMENT_LENGTH) ??
+        DEFAULT_MAX_DOCUMENT_LENGTH,
       logDestination: combinedOptions.mongodbLogPath
     };
   }

test/unit/mongo_logger.test.ts

@@ -19,7 +19,9 @@ import {
   CONNECTION_POOL_CREATED,
   CONNECTION_POOL_READY,
   CONNECTION_READY,
+  DEFAULT_MAX_DOCUMENT_LENGTH,
   Log,
+  maybeTruncate,
   MongoDBLogWritable,
   MongoLogger,
   MongoLoggerOptions,
@@ -1212,3 +1214,24 @@ describe('class MongoLogger', function () {
     }
   });
 });
+
+describe('maybeTruncate', function () {
+  const largeDoc = {};
+  before(function () {
+    for (let i = 0; i < 1000; i++) {
+      largeDoc[`test${i}`] = `Hello_${i}`;
+    }
+  });
+
+  context('when maxDocumentLength = 0', function () {
+    it('does not truncate document', function () {
+      const ejson = EJSON.stringify(largeDoc);
+      expect(ejson).to.equal(maybeTruncate(ejson, 0));
+    });
+  });
+
+  context('when maxDocumentLength is non-zero', function () {
+    context('when document has length greater than maxDocumentLength', function () {});
+    context('when document has length less than or equal to maxDocumentLength', function () {});
+  });
+});