@app.task()
def my_taskA(a, b, c):
	print("doing something here...")
@app.task()
def my_taskB(x, y):
	print("doing something here...")

task_queues=(
    Queue('default', routing_key='default'),
    Queue('other', routing_key='other'),

@app.task(queue='other')
def parse_something():
	pass

Queue('other', routing_key='other_high'),
Queue('other', routing_key='other_low'),

task_routes={
	# see
	# http://docs.celeryproject.org/en/latest/userguide/configuration.html#std:setting-task_routes
	# http://docs.celeryproject.org/en/latest/userguide/routing.html#routing-basics
	'path.to.task' : {
		'queue': 'other',
		'routing_key': 'other_high'
	},
	'path.to.task' : {
		'queue': 'other',
		'routing_key': 'other_low'
	},
}

celery worker -E -l INFO -n workerA -Q other_high
celery worker -E -l INFO -n workerB -Q other_low

@app.task(bind=True, default_retry_delay=300, max_retries=5)
def my_task_A():
	try:
		print("doing stuff here...")
	except SomeNetworkException as e:
		print("maybe do some clenup here....")
		self.retry(e)

import requests
from myproject.tasks import app  # app is your celery application
from myproject.exceptions import InvalidUserInput
from utils.mail import api_send_mail
@app.task(bind=True, max_retries=3)
def send_mail(self, recipients, sender_email, subject, body):
	"""Send a plaintext email with argument subject, sender and body to a list of recipients."""
	try:
		data = api_send_mail(recipients, sender_email, subject, body)
	except InvalidUserInput:
		# No need to retry as the user provided an invalid input
		raise
	except Exception as exc:
		# Any other exception. Log the exception to sentry and retry in 10s.
		sentrycli.captureException()
		self.retry(countdown=10, exc=exc)
	return data

task_soft_time_limit = 600   # 600 seconds

from celery.exceptions import SoftTimeLimitExceeded
@app.task
def mytask():
	try:
		return do_work()
	except SoftTimeLimitExceeded:
		cleanup_in_a_hurry()

@app.task(
	bind=True,
	max_retries=3,
	soft_time_limit=5 # time limit is in seconds.
)
def send_mail(self, recipients, sender_email, subject, body):
	...

from myproject.tasks import app
class BaseTask(app.Task):
	"""Abstract base class for all tasks in my app."""
	abstract = True
	def on_retry(self, exc, task_id, args, kwargs, einfo):
		"""Log the exceptions to sentry at retry."""
		sentrycli.captureException(exc)
		super(BaseTask, self).on_retry(exc, task_id, args, kwargs, einfo)
	def on_failure(self, exc, task_id, args, kwargs, einfo):
		"""Log the exceptions to sentry."""
		sentrycli.captureException(exc)
		super(BaseTask, self).on_failure(exc, task_id, args, kwargs, einfo)

@app.task(
	bind=True,
	max_retries=3,
	soft_time_limit=5,
	base=BaseTask)
def send_mail(self, recipients, sender_email, subject, body):
	"""Send a plaintext email with argument subject, sender and body to a list of recipients."""
	try:
		data = api_send_mail(recipients, sender_email, subject, body)
	except InvalidUserInput:
		raise
	except Exception as exc:
		self.retry(countdown=backoff(self.request.retries), exc=exc)
	return data

class handle_event(BaseTask):   # BaseTask inherits from app.Task
	def validate_input(self, event):
		...
	def get_or_create_model(self, event):
		...
	def stream_event(self, event):
		...
	def run(self, event):
		if not self.validate_intput(event):
			raise InvalidInput(event)
		try:
			model = self.get_or_create_model(event)
			self.call_hooks(event)
			self.persist_model(event)
		except Exception as exc:
			self.retry(countdown=backoff(self.request.retries), exc=exc)
		else:
			self.stream_event(event)

celery -A proj worker -l info -Ofair

--concurrency=1

celery -A proj worker -P eventlet -c 10

root 	ALL=(ALL:ALL)  ALL

user hostname=(runas-user:runas-group) command

usermod -aG sudo einverne

sudo update-alternatives --config editor

sudo:x:27:username,username1

sudo cat /etc/passwd

sudo -u demo whoami
[sudo] password for einverne:
demo

sudo history
[sudo] password for einverne:
sudo: history: command not found

sudo bash

sudo !4

:w !sudo tee %

sudo -- bash -c 'pwd; id;'

sudo -l

# User privilege specification
username ALL=(ALL) NOPASSWD:ALL 单独配置一个用户

# Allow members of group sudo to execute any command
%sudo ALL=(ALL) NOPASSWD:ALL 配置一组用户

einverne ALL=(ALL) NOPASSWD: /bin/echo /bin/ls

ls -l /usr/bin/sudo
-rwsr-xr-x 1 root root 145040 Jun 13  2017 /usr/bin/sudo

id
uid=1002(einverne) gid=1002(einverne) groups=1002(einverne)

sudo id
uid=0(root) gid=0(root) groups=0(root)

git merge --squash <branch name>
# after
git commit -s
# then write your commit message

git branch --set-upstream-to=origin/master master

git push -u origin master

git rebase -i HEAD~N

git branch -m <new-name>

git whatchanged --since='2 weeks ago'

curl -i https://git.io -F "url=https://github.com/einverne"
HTTP/1.1 100 Continue

HTTP/1.1 201 Created
Server: Cowboy
Connection: keep-alive
Date: Sun, 14 May 2017 03:05:40 GMT
Status: 201 Created
Content-Type: text/html;charset=utf-8
Location: https://git.io/v97cY
Content-Length: 27
X-Xss-Protection: 1; mode=block
X-Content-Type-Options: nosniff
X-Frame-Options: SAMEORIGIN
X-Runtime: 0.312051
X-Node: 09a65813-05e0-40a2-a9bf-6dd88da1cdbc
X-Revision: 392798d237fc1aa5cd55cada10d2945773e741a8
Strict-Transport-Security: max-age=31536000; includeSubDomains
Via: 1.1 vegur

curl -i https://git.io/v97cY

HTTP/1.1 302 Found
Server: Cowboy
Connection: keep-alive
Date: Sun, 14 May 2017 03:06:58 GMT
Status: 302 Found
Content-Type: text/html;charset=utf-8
Location: https://github.com/einverne
Content-Length: 0
X-Xss-Protection: 1; mode=block
X-Content-Type-Options: nosniff
X-Frame-Options: SAMEORIGIN
X-Runtime: 0.005605
X-Node: d567f758-ba0e-4e8b-95ba-b6a80730cc20
X-Revision: 392798d237fc1aa5cd55cada10d2945773e741a8
Strict-Transport-Security: max-age=31536000; includeSubDomains
Via: 1.1 vegur

curl -i https://git.io -F "url=https://github.com/...." -F "code=abcd"

create table links
(
    shortLink not null
        unique,
    longLink,
    timestamp,
    ip,
    redirectMethod
);

sudo add-apt-repository -y ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java8-installer

wget http://..../jdk-8u91-linux-x64.tar.gz
tar -zxvf jdk-8u91-linux-x64.tar.gz -C /opt/java/
vim ~/.zshrc # or ~/.bashrc

export JAVA_HOME=/opt/java/jdk1.8.0_91/
export PATH="$PATH:$JAVA_HOME/bin/"

source ~/.zshrc

$ sudo update-alternatives --config java
There are 3 choices for the alternative java (providing /usr/bin/java).
  Selection    Path                                            Priority   Status
------------------------------------------------------------
* 0            /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java   1071      auto mode
  1            /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java   1061      manual mode
  2            /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java   1071      manual mode
  3            /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java   1081      manual mode
Press enter to keep the current choice[*], or type selection number:

engine = create_engine('mysql+mysqldb://root:password@127.0.0.1:3306/dbname')

#!/usr/bin/env python
#-*- coding: utf-8 -*-

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from sqlalchemy.pool import NullPool

engine = create_engine('mysql+mysqldb://root:password@127.0.0.1:3306/dbname', poolclass=NullPool)
Session = sessionmaker(bind=engine)
session = Session()
usr_obj_list = session.query(UsrObj).all()
print usr_obj_list[0].id
session.close()

engine = create_engine('postgresql://postgres@127.0.0.1/dbname')

ssh-keygen -t rsa

scp ~/.ssh/id_rsa.pub username@hostname:~/.ssh/authorized_keys
# or
ssh-copy-id -i ~/.ssh/id_rsa.pub username@hostname

cat id_rsa.pub >> .ssh/authorized_keys

vim /etc/ssh/sshd_config

ClientAliveInterval 30
ClientAliveCountMax 60

sudo service ssh restart

sudo apt-get install openssh-server

vim /etc/ssh/ssh_config

ServerAliveInterval 30
ServerAliveCountMax 60

ControlMaster auto
ControlPath ~/.ssh/connection-%r@%h:%p

ControlPersist 4h

ForwardAgent yes

Host *
	ForwardAgent yes
	ServerAliveInterval 3
	ServerAliveCountMax 20
	TCPKeepAlive no
	ControlMaster auto
	ControlPath ~/.ssh/connection-%r@%h:%p
	ControlPersist 4h
	Compression yes

sudo apt update
sudo apt-get install mysql-server
sudo mysql_secure_installation

sudo mysql_secure_installation

sudo mysql -u root -p

sudo /etc/init.d/mysql {start | stop | status | restart}

sudo service mysql {start | stop | status | restart}

net start mysql

net start mssqlserver
# 或者重启 tomcat
net start tomcat6

mysql -u [root] -p

SHOW DATABASES;

mysql> show DATABASES;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| parker             |
| performance_schema |
| sys                |
| test               |
| youku              |
+--------------------+
7 rows in set (0.00 sec)

CREATE DATABASE dbname;

DROP DATABASE dbname;

USE dbname;

SHOW tables;

CREATE TABLE table_name (id INT NOT NULL PRIMARY KEY AUTO_INCREMENT, name VARCHAR(20) , signup_date DATE);

DESCRIBE table_name;

ALTER TABLE table_name **ADD COLUMN** [column] VARCHAR(40);

ALTER TABLE [table] ADD COLUMN [column] int NOT NULL AUTO_INCREMENT PRIMARY KEY;

ALTER TABLE table_name **ADD** email VARCHAR(40) AFTER name;

ALTER TABLE table_name **DROP** column

ALTER TABLE tablename **MODIFY COLUMN** column_name VARCHAR(20);
ALTER TABLE tablename **ALTER COLUMN** column_name VARCHAR(20);

ALTER TABLE [table]  ADD primary key(column1, column2);

ALTER TABLE [table]  DROP PRIMARY KEY, ADD primary key(column1, column2);

ALTER TABLE origin_table_name **RENAME TO** new_table_name

INSERT INTO `table_name` (`name`, `signup_date`) VALUES ("Verne", "2017-05-01");

UPDATE [table] SET [column] = 'Y' WHERE `potluck`.`name` ='Sandy';

DELETE from table_name where column_name = "value";

SELECT COUNT([column]) FROM [table];

SELECT * FROM [table] WHERE [column] LIKE '%value%';

SELECT * FROM [table] WHERE [column] ORDER BY [column] ASC LIMIT [value];

TRUNCATE table [table]

show create table [table_name];

SHOW INDEX FROM [table];

mysqldump -u [username] -p [database] > db_backup.sql
mysqldump -u [username] -p [database] [table_name] > db_backup.sql

mysql -u [username] -p [database] < db_backup.sql
mysql -u [username] -p -h localhost [database] < db_backup.sql

SELECT User,Host FROM mysql.user;

CREATE USER 'username'@'localhost' IDENTIFIED BY 'password';

mysql> set global validate_password_policy=0;

mysql> select @@validate_password_length;

GRANT ALL ON [database].* TO 'user'@'localhost';

GRANT ALL PRIVILEGES ON *.* TO 'user'@'localhost' WITH GRANT OPTION;

mysqladmin -u root -p old_password password new_password

DROP USER 'user1'@'localhost';

uninstall plugin validate_password;
// MySQL 8.0.4 以上
UNINSTALL COMPONENT 'file://component_validate_password';

alter table old_db.table_name rename new_db.table_name

mysql -h host -u user -p < batch-file

#bind-address = 127.0.0.1

mysql -u root –p
mysql>use mysql;
mysql>update user set host = '%' where user = 'root';
mysql>select host, user from user;

SHOW VARIABLES LIKE 'validate_password%';

mysql> SHOW VARIABLES LIKE 'validate_password%';
+--------------------------------------+--------+
| Variable_name                        | Value  |
+--------------------------------------+--------+
| validate_password_check_user_name    | OFF    |
| validate_password_dictionary_file    |        |
| validate_password_length             | 8      |
| validate_password_mixed_case_count   | 1      |
| validate_password_number_count       | 1      |
| validate_password_policy             | MEDIUM |
| validate_password_special_char_count | 1      |
+--------------------------------------+--------+
7 rows in set (0.01 sec)

SET GLOBAL validate_password_policy=MEDIUM;        // LOW  MEDIUM HIGH
SET GLOBAL validate_password_policy=1;        // Low=0 Medium=1 High=2

mysql> CREATE USER 'einverne'@'localhost' IDENTIFIED BY 'some_pass';
mysql> GRANT ALL PRIVILEGES ON *.* TO 'einverne'@'localhost'
	->     WITH GRANT OPTION;
mysql> CREATE USER 'einverne'@'%' IDENTIFIED BY 'some_pass';
mysql> GRANT ALL PRIVILEGES ON *.* TO 'einverne'@'%'
	->     WITH GRANT OPTION;

FLUSH PRIVILEGES;

ERROR 1698 (28000): Access denied for user 'root'@'localhost'
MariaDB [(none)]> SELECT User, Host, plugin FROM mysql.user;
+------+-----------+-------------+
| User | Host      | plugin      |
+------+-----------+-------------+
| root | localhost | unix_socket |
+------+-----------+-------------+
1 row in set (0.00 sec)

sudo mysql -u root
mysql> USE mysql;
mysql> UPDATE user set plugin='mysql_native_password' WHERE user='root';
mysql>FLUSH PRIVILEGES;
mysql>exit

sudo service mysql restart

$ sudo mysql -u root # I had to use "sudo" since is new installation

mysql> USE mysql;
mysql> CREATE USER 'YOUR_SYSTEM_USER'@'localhost' IDENTIFIED BY 'YOUR_PASSWD';
mysql> GRANT ALL PRIVILEGES ON *.* TO 'YOUR_SYSTEM_USER'@'localhost';
mysql> UPDATE user SET plugin='auth_socket' WHERE User='YOUR_SYSTEM_USER';
mysql> FLUSH PRIVILEGES;
mysql> exit;

$ sudo service mysql restart

mysql> help
  ...
  \g  go  Send command to mysql server.
  \G  ego Send command to mysql server, display result vertically.
  ...

man mysql...
  ...
  --vertical, -E
  Print query output rows vertically (one line per column value).
  Without this option, you can specify vertical output for individual
  statements by terminating them with \G.
  ...

#!/usr/bin/env python3
# -*- coding:utf-8 -*-

import MySQLdb

"""
pip install MySQL-python
MySQLdb 是用于 Python 链接 Mysql 数据库的接口，它实现了 Python 数据库 API 规范 V2.0，基于 MySQL C API 上建立的。

在使用 Python 连接之前确保已经有数据表建立

> mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 25
Server version: 5.7.18-0ubuntu0.16.04.1 (Ubuntu)

Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> SHOW DATABASES;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| spy                |
| sys                |
+--------------------+
5 rows in set (0.00 sec)

mysql> CREATE DATABASE testdb;
Query OK, 1 row affected (0.00 sec)

mysql> CREATE USER 'testuser'@'localhost' IDENTIFIED BY '12345678';
Query OK, 0 rows affected (0.01 sec)

mysql> USE testdb;
Database changed
mysql> GRANT ALL ON testdb.* TO 'testuser'@'localhost';
Query OK, 0 rows affected (0.00 sec)

"""

con = MySQLdb.connect('localhost', 'testuser', '12345678', 'testdb', charset='utf8')


def create_table():
    with con:
        cur = con.cursor()
        cur.execute("DROP TABLE IF EXISTS Users")
        cur.execute("CREATE TABLE Users(id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(50))")


def insert(name):
    with con:
        cur = con.cursor()
        cur.execute("INSERT INTO Users(name) VALUES('" + name + "')")


def get():
    with con:
        cur = con.cursor()
        cur.execute("SELECT * FROM Users")

        rows = cur.fetchall()
        for row in rows:
            print row


def update(old_name, new_name):
    with con:
        cur = con.cursor()
        cur.execute("UPDATE Users SET name = %s WHERE name = %s", (new_name, old_name))


def transaction():
    try:
        con.cursor()
        insert("CC")
        insert("David")
        insert("Einstein")
        con.commit()
    except MySQLdb.Error, e:
        if con:
            con.rollback()
        print "Error %d: %s" % (e.args[0],e.args[1])


if __name__ == '__main__':

    try:

        cur = con.cursor()
        sql = "SELECT VERSION()"
        cur.execute(sql)

        version = cur.fetchone()
        print "MySQL version : %s " % version
    except MySQLdb.Error, e:
        print "Error %d: %s" % (e.args[0], e.args[1])
        if con:
            con.close()

    create_table()
    insert("Alex")
    insert("Verne")
    get()
    update("Alex", "Bob")
    get()
    transaction()
    get()
    if con:
        con.close()

pip install mycli

mycli [OPTIONS] [DATABASE]

Options:
  -h, --host TEXT               Host address of the database.
  -P, --port INTEGER            Port number to use for connection. Honors
                                $MYSQL_TCP_PORT
  -u, --user TEXT               User name to connect to the database.
  -S, --socket TEXT             The socket file to use for connection.
  -p, --password TEXT           Password to connect to the database
  --pass TEXT                   Password to connect to the database
  --ssl-ca PATH                 CA file in PEM format
  --ssl-capath TEXT             CA directory
  --ssl-cert PATH               X509 cert in PEM format
  --ssl-key PATH                X509 key in PEM format
  --ssl-cipher TEXT             SSL cipher to use
  --ssl-verify-server-cert      Verify server's "Common Name" in its cert
                                against hostname used when connecting. This
                                option is disabled by default
  -v, --version                 Version of mycli.
  -D, --database TEXT           Database to use.
  -R, --prompt TEXT             Prompt format (Default: "\t \u@\h:\d> ")
  -l, --logfile FILENAME        Log every query and its results to a file.
  --defaults-group-suffix TEXT  Read config group with the specified suffix.
  --defaults-file PATH          Only read default options from the given file
  --myclirc PATH                Location of myclirc file.
  --auto-vertical-output        Automatically switch to vertical output mode
                                if the result is wider than the terminal
                                width.
  -t, --table                   Display batch output in table format.
  --csv                         Display batch output in CSV format.
  --warn / --no-warn            Warn before running a destructive query.
  --local-infile BOOLEAN        Enable/disable LOAD DATA LOCAL INFILE.
  --login-path TEXT             Read this path from the login file.
  -e, --execute TEXT            Execute query to the database.
  --help                        Show this message and exit.