Question

我想在RQ工作器（rq_worker.py）中重用数据库连接。此连接在预加载库（task.py）中建立。之后，将两个作业添加到RQ队列（rq_queue.py）。

如果我不使用Docker，一切都很好。但是，如果我在容器中运行MySQL：

OperationalError（“ MySQL Connection not available。”）。
MySQL终止连接并显示一条“读取通信数据包时出错”消息

我已经尝试增加max_allowed_packet （https://dba.stackexchange.com/questions/40899/mysql-error-reading-communication-packets）失败

# rq_worker.py

from redis import Redis
from rq import Connection, Worker

# Preload library
import task

with Connection(Redis()):
    w = Worker('default')
    w.work()

# task.py

import mysql.connector

mysql_conn = mysql.connector.connect(
    user='_user', password='_password', database='_database')

def print_mysql_version():
    cursor = mysql_conn.cursor()
    cursor.execute("SELECT version();")
    print(cursor.fetchone())
    cursor.close()

# rq_queue.py

from redis import Redis
from rq import Queue
from task import print_mysql_version

task_queue = Queue(connection=Redis())
task_queue.enqueue(print_mysql_version)
task_queue.enqueue(print_mysql_version)

没有Docker：

sudo mysql -uroot -e"create database _database; \
    create user _user@localhost identified by '_password'; \
    grant all on _database.* to _user@localhost;"

RQ worker 'rq:worker:ipa.4109' started, version 0.13.0
Listening on default...
Cleaning registries for queue: default
default: task.print_mysql_version() (22649b0b-1089-4729-9995-8c850bb7c49b)
('5.7.25-0ubuntu0.18.04.2',)
default: Job OK (22649b0b-1089-4729-9995-8c850bb7c49b)
Result is kept for 500 seconds
default: task.print_mysql_version() (60fca63f-e0ad-4868-ac1e-637edf00b226)
('5.7.25-0ubuntu0.18.04.2',)
default: Job OK (60fca63f-e0ad-4868-ac1e-637edf00b226)
Result is kept for 500 seconds

使用Docker

docker run -p 3306:3306 -e MYSQL_DATABASE=_database -e MYSQL_USER=_user \
    -e MYSQL_PASSWORD=_password -e MYSQL_ALLOW_EMPTY_PASSWORD=yes \
    mysql:5.7.25

RQ worker 'rq:worker:ipa.5080' started, version 0.13.0
*** Listening on default...
Cleaning registries for queue: default
default: task.print_mysql_version() (1b53a0d5-6a0e-4704-a3f5-4cc7f0cb71d7)
('5.7.25',)
default: Job OK (1b53a0d5-6a0e-4704-a3f5-4cc7f0cb71d7)
Result is kept for 500 seconds
default: task.print_mysql_version() (f9c2928d-3d84-4041-b5bb-e650f43f05e1)
mysql.connector.errors.OperationalError: MySQL Connection not available.
Traceback (most recent call last):
  File "/home/user/projects/patfinder/venv_prod/lib/python3.6/site-packages/rq/worker.py", line 799, in perform_job
    rv = job.perform()
  File "/home/user/projects/patfinder/venv_prod/lib/python3.6/site-packages/rq/job.py", line 600, in perform
    self._result = self._execute()
  File "/home/user/projects/patfinder/venv_prod/lib/python3.6/site-packages/rq/job.py", line 606, in _execute
    return self.func(*self.args, **self.kwargs)
  File "/home/user/projects/patfinder/rq_test/task.py", line 10, in print_mysql_version
    cursor = mysql_conn.cursor()
  File "/home/user/projects/patfinder/venv_prod/lib/python3.6/site-packages/mysql/connector/connection_cext.py", line 447, in cursor
    raise errors.OperationalError("MySQL Connection not available.")
mysql.connector.errors.OperationalError: MySQL Connection not available.
Traceback (most recent call last):
  File "/home/user/projects/patfinder/venv_prod/lib/python3.6/site-packages/rq/worker.py", line 799, in perform_job
    rv = job.perform()
  File "/home/user/projects/patfinder/venv_prod/lib/python3.6/site-packages/rq/job.py", line 600, in perform
    self._result = self._execute()
  File "/home/user/projects/patfinder/venv_prod/lib/python3.6/site-packages/rq/job.py", line 606, in _execute
    return self.func(*self.args, **self.kwargs)
  File "/home/user/projects/patfinder/rq_test/task.py", line 10, in print_mysql_version
    cursor = mysql_conn.cursor()
  File "/home/user/projects/patfinder/venv_prod/lib/python3.6/site-packages/mysql/connector/connection_cext.py", line 447, in cursor
    raise errors.OperationalError("MySQL Connection not available.")
mysql.connector.errors.OperationalError: MySQL Connection not available.
Moving job to 'failed' queue

2 [Note] Aborted connection 2 to db: '_database' user: '_user' host: '172.17.0.1' (Got an error reading communication packets)

RQ工作者失去与dockerized MySQL的连接

0 个答案: