nNjinDEv

1import eventlet
2eventlet.monkey_patch()
3
4import itertools
5import pymysql
6import random
7from eventlet.green import time
8import greenlet
9
10def connect():
11    return pymysql.connect(user="scott", passwd="tiger", host="127.0.0.1", db="test")
12
13
14greenlet_id = itertools.count(1)
15
16
17def do_work(connections, conn_index):
18    our_id = next(greenlet_id)
19    conn = connections[conn_index]
20    while True:
21        try:
22            print("greenlet %d working..." % our_id)
23            cursor = conn.cursor()
24            for i in range(10):
25                cursor.execute(
26                    "insert into stuff (data) values (%s)",
27                    (("some_data_%f" % random.random()), )
28                )
29            cursor.close()
30            conn.commit()
31
32            cursor = conn.cursor()
33            cursor.execute("select sleep(%s)", (random.random(), ))
34            time.sleep(random.random())
35            if cursor.description is None:
36                raise Exception("cursor.description not supposed to be none")
37            cursor.fetchall()
38            cursor.close()
39            conn.rollback()
40            time.sleep(random.random())
41        except pymysql.Error as err:
42            print("error occurred, invalidating connection: %s" % err)
43            conn.rollback()
44            conn.close()
45            conn = connections[conn_index] = connect()
46        except Exception as err:
47            print("totally unexpected error occurred: %r" % err)
48        except greenlet.GreenletExit as ex:
49            print("exit exception: %r" % ex)
50            if ensure_greenlet_exit_handled:
51                conn.close()
52                conn = connections[conn_index] = connect()
53            break
54
55if __name__ == '__main__':
56    ensure_greenlet_exit_handled = False
57
58    num = 10
59
60    conn = connect()
61    cursor = conn.cursor()
62    cursor.execute("drop table if exists stuff")
63    cursor.execute(
64        "create table stuff(id integer primary key auto_increment, "
65        "data varchar(200))")
66    cursor.close()
67    conn.commit()
68
69    connections = [connect() for i in range(num)]
70
71    greenlets = [
72        eventlet.spawn(do_work, connections, idx)
73        for idx in range(num)]
74
75    while True:
76        for idx in range(num):
77            time.sleep(random.random())
78            print("kill...")
79            eventlet.greenthread.kill(greenlets[idx])
80            time.sleep(.5)
81            greenlets[idx] = eventlet.spawn(do_work, connections, idx)