Add utility merge_db.py.

utilities/merge_db.py

@@ -0,0 +1,51 @@
+import argparse
+import os
+import sqlite3
+import sys
+
+MIGRATE_QUERY = '''
+INSERT INTO {tablename}
+SELECT othertable.* FROM other.{tablename} othertable
+LEFT JOIN {tablename} mytable ON mytable.id == othertable.id
+WHERE mytable.id IS NULL AND {where_clause};
+'''
+
+def _migrate_helper(sql, tablename, where_clause='1==1'):
+    query = MIGRATE_QUERY.format(tablename=tablename, where_clause=where_clause)
+    print(query)
+
+    oldcount = sql.execute('SELECT count(*) FROM %s' % tablename).fetchone()[0]
+    sql.execute(query)
+    sql.commit()
+
+    newcount = sql.execute('SELECT count(*) FROM %s' % tablename).fetchone()[0]
+    print('Gained %d items.' % (newcount - oldcount))
+
+def merge_db(from_db_path, to_db_path, channel):
+    to_db = sqlite3.connect(to_db_path)
+    from_db = sqlite3.connect(from_db_path)
+
+    to_db.execute('ATTACH DATABASE "%s" AS other' % from_db_path)
+    if channel == '*':
+        _migrate_helper(to_db, 'channels')
+        _migrate_helper(to_db, 'videos')
+    else:
+        _migrate_helper(to_db, 'channels', where_clause=f'othertable.id == "{channel}"')
+        _migrate_helper(to_db, 'videos', where_clause=f'othertable.author_id == "{channel}"')
+
+def merge_db_argparse(args):
+    return merge_db(args.from_db_path, args.to_db_path, args.channel)
+
+def main(argv):
+    parser = argparse.ArgumentParser(description=__doc__)
+
+    parser.add_argument('--from_db_path', dest='from_db_path', required=True)
+    parser.add_argument('--to_db_path', dest='to_db_path', required=True)
+    parser.add_argument('--channel', dest='channel', required=True)
+    parser.set_defaults(func=merge_db_argparse)
+
+    args = parser.parse_args(argv)
+    return args.func(args)
+
+if __name__ == '__main__':
+    raise SystemExit(main(sys.argv[1:]))