feat: implement background process logging and cleanup (#21189)

packages/cli/src/utils/logCleanup.ts

@@ -0,0 +1,66 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { promises as fs } from 'node:fs';
+import * as path from 'node:path';
+import { ShellExecutionService, debugLogger } from '@google/gemini-cli-core';
+
+const RETENTION_PERIOD_MS = 7 * 24 * 60 * 60 * 1000; // 7 days
+
+/**
+ * Cleans up background process log files older than 7 days.
+ * Scans ~/.gemini/tmp/background-processes/ for .log files.
+ *
+ * @param debugMode Whether to log detailed debug information.
+ */
+export async function cleanupBackgroundLogs(
+  debugMode: boolean = false,
+): Promise<void> {
+  try {
+    const logDir = ShellExecutionService.getLogDir();
+
+    // Check if the directory exists
+    try {
+      await fs.access(logDir);
+    } catch {
+      // Directory doesn't exist, nothing to clean up
+      return;
+    }
+
+    const entries = await fs.readdir(logDir, { withFileTypes: true });
+    const now = Date.now();
+    let deletedCount = 0;
+
+    for (const entry of entries) {
+      if (entry.isFile() && entry.name.endsWith('.log')) {
+        const filePath = path.join(logDir, entry.name);
+        try {
+          const stats = await fs.stat(filePath);
+          if (now - stats.mtime.getTime() > RETENTION_PERIOD_MS) {
+            await fs.unlink(filePath);
+            deletedCount++;
+          }
+        } catch (error) {
+          if (debugMode) {
+            debugLogger.debug(
+              `Failed to process log file ${entry.name}:`,
+              error,
+            );
+          }
+        }
+      }
+    }
+
+    if (deletedCount > 0 && debugMode) {
+      debugLogger.debug(`Cleaned up ${deletedCount} expired background logs.`);
+    }
+  } catch (error) {
+    // Best-effort cleanup, don't let it crash the CLI
+    if (debugMode) {
+      debugLogger.warn('Background log cleanup failed:', error);
+    }
+  }
+}