如何创建到 SQL 服务器的数据库连接并将连接错误消息发送到 Python 中的电子邮件？

Question

我已经尝试编写 Python 3 代码来连接到 SQL 服务器数据库，条件如下：-

如果数据库连接出现错误，则会在休眠 5 秒后重试连接。
目前最大重试次数为2次。可以更改为代码中的任何其他数字。
一旦达到最大重试次数但仍然存在连接错误，脚本会向我发送电子邮件通知我错误。

我的代码如下。它适用于最大尝试，但外观存在问题，以至于它开始不断发送电子邮件，直到我停止运行为止。看起来像一个无限循环，很可能在第二个 while 语句中。谁能指出问题出在哪里以及如何修复代码。

import configparser 
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
import smtplib
import mimetypes
import email.mime.application

config = configparser.ConfigParser()  
Driver='SQL Server'
config.read('connection.ini')  
#Context is specific to my configuration.ini file that has the connection details
server = config['Context']['host']  
db = config['Context']['database']  
user = config['Context']['user']  
password = config['Context']['pwd'] 

retry_flag = True  
retry_count  = 0 
max_retries = 2 

while retry_flag and  retry_count < max_retries:
 try:
    cnxn_str = pyodbc.connect(driver=Driver, host=server, user=user,password=password, database=db)
    retry_flag = False
except Exception as e:
    error = str(e)
    print(error)
    print("Retry after  5 sec")
    retry_count = retry_count+1
          
    time.sleep(5)
   
    while retry_count == max_retries:
        
        smtp_ssl_host = config['Context']['smtp_ssl_host']
        smtp_ssl_port = config['Context']['smtp_ssl_port']
        email_user = config['Context']['email_user']
        email_to = config['Context']['email_to']
        email_pass =config['Context']['email_pass'] 


        msg = MIMEMultipart()
        msg['Subject'] = "Database Connection Error"
        msg['From'] = email_user
        msg['To'] = email_to
        s = smtplib.SMTP_SSL(smtp_ssl_host, smtp_ssl_port)
        s.login(email_user, email_pass)

        txt = MIMEText("Database connection failed earlier. Please re-run the script manually.")
        msg.attach(txt)
        s.send_message(msg)      
        s.quit()

Answer 1

正确，您的第二个 while 永远运行，因为当您进入该循环时该条件始终为真（请勿更改 retry_counts）。

您可以将其更改为 if 而不是 while，例如（我也加了一个try/catch）

if retry_count == max_retries:
 try:
  smtp_ssl_host = config['Context']['smtp_ssl_host']
        smtp_ssl_port = config['Context']['smtp_ssl_port']
        email_user = config['Context']['email_user']
        email_to = config['Context']['email_to']
        email_pass =config['Context']['email_pass'] 

        msg = MIMEMultipart()
        msg['Subject'] = "Database Connection Error"
        msg['From'] = email_user
        msg['To'] = email_to
        s = smtplib.SMTP_SSL(smtp_ssl_host, smtp_ssl_port)
        s.login(email_user, email_pass)

        txt = MIMEText("Database connection failed earlier. Please re-run the script manually.")
        msg.attach(txt)
        s.send_message(msg)      
        s.quit()   
   except Exception as e:
        print(e)

或者在最后增加 retry_counts。不过，在我看来，这不会那么可读/“漂亮”。

如何创建到 SQL 服务器的数据库连接并将连接错误消息发送到 Python 中的电子邮件？

How do I create a database connection to SQL Server and send out connection error messages to an email in Python?

python

sql-server

automation

smtplib