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給Python中的MySQLdb模塊添加超時功能的教程

更新時間：2015年05月05日 11:56:46 投稿：goldensun

這篇文章主要介紹了給Python中的MySQLdb模塊添加超時功能的教程,timeout功能在服務(wù)器的運維當(dāng)中非常有用,需要的朋友可以參考下

使用Python操作MySQL數(shù)據(jù)庫的時候常使用MySQLdb這個模塊。

今天在開發(fā)的過程發(fā)現(xiàn)MySQLdb.connect有些參數(shù)沒法設(shè)置。通過這個頁面我們可以看到在connect的時候，可以設(shè)置的option和client_flags和MySQL c api相比差不少。

一個很重要的參數(shù) MYSQL_OPT_READ_TIMEOUT沒法設(shè)置，這個參數(shù)如果不設(shè)置，極致狀況MySQL處于hang住，自動切換IP漂移，客戶端無法重連到新MySQL。

給MySQLdb加Option很簡單，只要修改_mysql.c這個把Python對象映射到MySQL操作的文件，添加參數(shù)，再加一段mysql_option即可。

下面是修改后的git diff 文件

?View Code BASH

diff --git a/_mysql.c b/_mysql.c
index d42cc54..61a9b34 100644
--- a/_mysql.c
+++ b/_mysql.c
@@ -489,9 +489,10 @@ _mysql_ConnectionObject_Initialize(
"named_pipe", "init_command",
"read_default_file", "read_default_group",
"client_flag", "ssl",
-                 "local_infile",
+                 "local_infile", "read_timeout",
NULL } ;
int connect_timeout = 0;
+    int read_timeout = 0;
int compress = -1, named_pipe = -1, local_infile = -1;
char *init_command=NULL,
*read_default_file=NULL,
@@ -500,7 +501,7 @@ _mysql_ConnectionObject_Initialize(
self-&gt;converter = NULL;
self-&gt;open = 0;
check_server_init(-1);
-    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|ssssisOiiisssiOi:connect",
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|ssssisOiiisssiOii:connect",
kwlist,
&amp;host, &amp;user, &amp;passwd, &amp;db,
&amp;port, &amp;unix_socket, &amp;conv,
@@ -509,7 +510,8 @@ _mysql_ConnectionObject_Initialize(
&amp;init_command, &amp;read_default_file,
&amp;read_default_group,
&amp;client_flag, &amp;ssl,
-                    &amp;local_infile /* DO NOT PATCH FOR RECONNECT, IDIOTS
+                    &amp;local_infile, &amp;read_timeout
+                    /* DO NOT PATCH FOR RECONNECT, IDIOTS
IF YOU DO THIS, I WILL NOT SUPPORT YOUR PACKAGES. */
))
return -1;
@@ -540,6 +542,12 @@ _mysql_ConnectionObject_Initialize(
mysql_options(&amp;(self-&gt;connection), MYSQL_OPT_CONNECT_TIMEOUT,
(char *)&amp;timeout);
}
+
+    if (read_timeout) {
+        unsigned int timeout = read_timeout;
+        mysql_options(&amp;(self-&gt;connection), MYSQL_OPT_READ_TIMEOUT, (char *)&amp;timeout);
+    }
+
if (compress != -1) {
mysql_options(&amp;(self-&gt;connection), MYSQL_OPT_COMPRESS, 0);
client_flag |= CLIENT_COMPRESS;

代碼修改完畢，python setup.py install 即可，如果出現(xiàn)mysql_config找不到的問題。你還要修改setup_posix.py文件。

hoterran@hoterran-laptop:~/Projects/MySQL-python-1.2.3$ git diff setup_posix.py
diff --git a/setup_posix.py b/setup_posix.py
index 86432f5..f4f08f1 100644
--- a/setup_posix.py
+++ b/setup_posix.py
@@ -23,7 +23,7 @@ def mysql_config(what):
     if ret/256 &gt; 1:
       raise EnvironmentError("%s not found" % (mysql_config.path,))
   return data
-mysql_config.path = "mysql_config"
+mysql_config.path = "/usr/local/mysql/bin/mysql_config"

 def get_config():
   import os, sys

編譯通過，我們來試試添加的read_timeout這個參數(shù)。

conn = MySQLdb.connect(host = DB_SERVER,user = DB_USERNAME,passwd = DB_PASSWORD,db = DB_NAME, port=int(DB_PORT), client_flag = 2, read_timeout = 10)

然后執(zhí)行語句前，你試著把mysql用gdb hang住10s后，python就會異常拋錯

OperationalError: (2013, 'Lost connection to MySQL server during query')
 >/home/hoterran/Projects/dbaas/trunk/dbtest.py(18)()
 >mydb.execute_sql(conn, sql)
(Pdb)
--Return--
> /home/hoterran/Projects/dbaas/trunk/dbtest.py(18)()-&gt;None
> mydb.execute_sql(conn, sql)
(Pdb)
OperationalError: (2013, 'Lost connection to MySQL server during query')
> <string>(1)<module>()->None

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