adding a change to fix database is locked error

Author: Ishan Roy

Diff for: .DS_Store

@@ -13,6 +13,7 @@
 import logging
 import shutil
 import sqlite3
+import time
 import tempfile
 from datetime import date
 from os import utime
@@ -49,7 +50,8 @@
 EPSS_METRIC_ID = 1
 CVSS_2_METRIC_ID = 2
 CVSS_3_METRIC_ID = 3
-
+MAX_RETRIES = 5  # Number of retries before failing
+RETRY_DELAY = 0.5  # Initial delay in seconds (will double on each retry)
 
 class CVEDB:
     """
@@ -763,18 +765,23 @@ def update_vendors(self, cve_data):
 
         return updated_severity, updated_affected
 
-    def db_open_and_get_cursor(self) -> sqlite3.Cursor:
-        """Opens connection to sqlite database, returns cursor object."""
-
-        if not self.connection:
-            self.connection = sqlite3.connect(self.dbpath)
-        if self.connection is not None:
-            cursor = self.connection.cursor()
-        if cursor is None:
-            # if this happens somsething has gone horribly wrong
-            LOGGER.error("Database cursor does not exist")
-            raise CVEDBError
-        return cursor
+    def db_open_and_get_cursor(self):
+    """Open the database connection with retry logic to handle 'database is locked' errors."""
+    retries = 0
+    while retries < MAX_RETRIES:
+        try:
+            self.connection = sqlite3.connect(self.dbpath, timeout=10)  # Extend timeout
+            self.connection.execute("PRAGMA journal_mode=WAL;")  # Improve concurrency
+            return self.connection.cursor()
+        except sqlite3.OperationalError as e:
+            if "database is locked" in str(e):
+                retries += 1
+                wait_time = RETRY_DELAY * (2 ** retries)  # Exponential backoff
+                print(f"Database locked, retrying in {wait_time:.2f} seconds...")
+                time.sleep(wait_time)
+            else:
+                raise  # Raise other errors
+    raise sqlite3.OperationalError("Database is locked, retry limit reached.")
 
     def db_close(self) -> None:
         """Closes connection to sqlite database."""