fix(core): truncate large telemetry log entries (#16769)

packages/core/src/utils/textUtils.test.ts

@@ -5,7 +5,7 @@
  */
 
 import { describe, it, expect } from 'vitest';
-import { safeLiteralReplace } from './textUtils.js';
+import { safeLiteralReplace, truncateString } from './textUtils.js';
 
 describe('safeLiteralReplace', () => {
   it('returns original string when oldString empty or not found', () => {
@@ -77,3 +77,25 @@ describe('safeLiteralReplace', () => {
     expect(safeLiteralReplace('abc', 'b', '$$')).toBe('a$$c');
   });
 });
+
+describe('truncateString', () => {
+  it('should not truncate string shorter than maxLength', () => {
+    expect(truncateString('abc', 5)).toBe('abc');
+  });
+
+  it('should not truncate string equal to maxLength', () => {
+    expect(truncateString('abcde', 5)).toBe('abcde');
+  });
+
+  it('should truncate string longer than maxLength and append default suffix', () => {
+    expect(truncateString('abcdef', 5)).toBe('abcde...[TRUNCATED]');
+  });
+
+  it('should truncate string longer than maxLength and append custom suffix', () => {
+    expect(truncateString('abcdef', 5, '...')).toBe('abcde...');
+  });
+
+  it('should handle empty string', () => {
+    expect(truncateString('', 5)).toBe('');
+  });
+});

packages/core/src/utils/textUtils.ts

@@ -53,3 +53,21 @@ export function isBinary(
   // If no NULL bytes were found in the sample, we assume it's text.
   return false;
 }
+
+/**
+ * Truncates a string to a maximum length, appending a suffix if truncated.
+ * @param str The string to truncate.
+ * @param maxLength The maximum length of the string.
+ * @param suffix The suffix to append if truncated (default: '...[TRUNCATED]').
+ * @returns The truncated string.
+ */
+export function truncateString(
+  str: string,
+  maxLength: number,
+  suffix = '...[TRUNCATED]',
+): string {
+  if (str.length <= maxLength) {
+    return str;
+  }
+  return str.slice(0, maxLength) + suffix;
+}