如何处理 "finally" 块中的异常？

Question

给定以下 Python 代码：

# Use impyla package to access Impala
from impala.dbapi import connect
import logging

def process():
    conn = connect(host=host, port=port)  # Mocking host and port
    try:
        cursor = conn.cursor()
        # Execute query and fetch result
    except:
        loggin.error("Task failed with some exception")
    finally:
        cursor.close()  # Exception here!
        conn.close()

与 Impala 的连接已创建。但由于 Impala 超时，cursor.close() 出现异常。

考虑到潜在异常，关闭 cursor 和 conn 的正确方法是什么？

Answer 1

您必须嵌套 try 块：

def process():
    conn = connect(host=host, port=port)  # Mocking host and port
    try:
        cursor = conn.cursor()
        try:
            # Execute query and fetch result
        finally:
            # here cursor may fail
            cursor.close()
    except:
        loggin.error("Task failed with some exception")
    finally:
        conn.close()

要避免这样的 try-finally 块，您可以使用 with-语句：

def process():
    conn = connect(host=host, port=port)  # Mocking host and port
    try:
        with conn.cursor() as cursor:
            # Execute query and fetch result
            # cursor is automatically closed
    except:
        loggin.error("Task failed with some exception")
    finally:
        conn.close()

如何处理 "finally" 块中的异常？

How to handle exception in the "finally" block?

python

impala

impyla