python fabric usage notes

fabric

The title is development, but at the same time, I have to do development, testing and operation and maintenance... Why is the task*3 not salary * 3 (o(╯□╰)o)

Recently, I have taken over more and more things. The release and operation and maintenance work is quite mechanical, and the frequency is quite high, which leads to a waste of time but has many advantages.

Fix bugs, test, submit the repository (2 minutes), ssh to the test environment for pull deployment (2 minutes), rsync to online machines A, B, C, D, E (1 minute) , ssh to the five machines of ABCDE respectively, and restart one by one (8-10 minutes) = 13-15 minutes

The frustrating thing is that each operation is the same, the command is the same, and the terrible thing is that in multiple On the machine, it is difficult to do it with a script on this machine. The main time is wasted on ssh, typing commands, and writing it as a script. It can be executed with one click. Take two minutes to look at the execution results

until I find out. Fabric

function

is a very powerful tool

can solidify the commands for automated deployment or multi-machine operation into a script

and some The operation and maintenance tools are very similar. I use it mainly because python...

is simple, easy to use and easy to use

Of course, you can also combine various shell commands, including ancient artifacts and modern weapons. Difference

Environment configuration

Install the corresponding package on the local machine and the target machine (note, both are required)

sudo easy_install fabric

It is currently version 1.6 (or use pip install, the same )

After installation, you can check whether the installation is successful

[ken@~$] which fab
/usr/local/bin/fab

After installation, you can browse the official documentation http://docs.fabfile.org/en/1.6/

Then, you can get started

hello world

First perform simple operations on the machine to get a preliminary understanding. The source of the example is the official website

Create a new py script: fabfile. py

def hello():
    print("Hello world!")

Command line execution:

[ken@~/tmp/fab$] fab hello
Hello world!
Done.

Note that fabfile does not need to be used as the file name here, but the file needs to be specified during execution

[ken@~/tmp/fab$] mv fabfile.py test.py
fabfile.py -> test.py
[ken@~/tmp/fab$] fab hello
Fatal error: Couldn't find any fabfiles!
Remember that -f can be used to specify fabfile path, and use -h for help.
Aborting.
[ken@~/tmp/fab$] fab -f test.py hello
Hello world!
Done.

With parameters:

Modify the fabfile.py script:

def hello(name, value):
    print("%s = %s!" % (name, value))

Execute

[ken@~/tmp/fab$] fab hello:name=age,value=20
age = 20!
Done.
[ken@~/tmp/fab$] fab hello:age,20
age = 20!
Done.

Perform native operation

Simple local operation:

from fabric.api import local
def lsfab():
    local('cd ~/tmp/fab')
    local('ls')

Result:

[ken@~/tmp/fab$] pwd;ls
/Users/ken/tmp/fab
fabfile.py   fabfile.pyc  test.py      test.pyc
[ken@~/tmp/fab$] fab -f test.py lsfab
[localhost] local: cd ~/tmp/fab
[localhost] local: ls
fabfile.py  fabfile.pyc test.py     test.pyc
Done.

The actual combat begins:

Assume that you have to submit a configuration file settings.py to the repository every day (conflicts are not considered here)

If it is a manual operation:

cd /home/project/test/conf/
git add settings.py
git commit -m 'daily update settings.py'
git pull origin
git push origin

In other words, you have to type these commands manually once a day. The so-called daily job is a mechanized job that is repeated every day. Let us see how to use it. How can fabric be done with one click: (In fact, it can be done directly with shell scripts, but the advantage of fab is not here. The main purpose here is to prepare for local + remote operations later. After all, writing one script for operations in two places is easy to maintain)

from fabric.api import local
def setting_ci():
    local("cd /home/project/test/conf/")
    local("git add settings.py")
    #后面你懂的，懒得敲了…..

Mixing and integrating remote operations

At this time, suppose you want to go to the project directory corresponding to /home/ken/project of machine A to update the configuration file

#!/usr/bin/env python
# encoding: utf-8
from fabric.api import local,cd,run
env.hosts=['user@ip:port',] #ssh要用到的参数
env.password = 'pwd'

def setting_ci():
    local('echo "add and commit settings in local"')
    #刚才的操作换到这里，你懂的
def update_setting_remote():
    print "remote update"
    with cd('~/temp'):   #cd用于进入某个目录
        run('ls -l | wc -l')  #远程操作用run
def update():
    setting_ci()
    update_setting_remote()

Then , execute it:

[ken@~/tmp/fab$] fab -f deploy.py update
[user@ip:port] Executing task 'update'
[localhost] local: echo "add and commit settings in local"
add and commit settings in local
remote update
[user@ip:port] run: ls -l | wc -l
[user@ip:port] out: 12
[user@ip:port] out:
Done.

Note that if env.password is not declared, an interaction requesting a password will pop up when executing to the corresponding machine

Multiple server mashup

To operate multiple servers, you need to configure multiple hosts

#!/usr/bin/env python
# encoding: utf-8
from fabric.api import *
#操作一致的服务器可以放在一组，同一组的执行同一套操作
env.roledefs = {
            'testserver': ['user1@host1:port1',],  
            'realserver': ['user2@host2:port2', ]
            }
#env.password = '这里不要用这种配置了，不可能要求密码都一致的，明文编写也不合适。打通所有ssh就行了'
@roles('testserver')
def task1():
    run('ls -l | wc -l')
@roles('realserver')
def task2():
    run('ls ~/temp/ | wc -l')
def dotask():
    execute(task1)
    execute(task2)

Result:

[ken@~/tmp/fab$] fab -f mult.py dotask
[user1@host1:port1] Executing task 'task1'
[user1@host1:port1] run: ls -l | wc -l
[user1@host1:port1] out: 9
[user1@host1:port1] out:
[user2@host2:port2] Executing task 'task2'
[user2@host2:port2] run: ls ~/temp/ | wc -l
[user2@host2:port2] out: 11
[user2@host2:port2] out:

Done.

Extension
1. Color

You can print colors in It is more eye-catching and convenient to view the operation result information

from fabric.colors import *

def show():
print green('success')
print red( 'fail')
Print yellow('yellow')
#fab -f color.py show

1.host, user, port, password configuration list, all written in one file

Or directly get it into the script, of course this is more...

env.hosts = [
'host1',
'host2'

]
env.passwords = { 
'host1': "pwdofhost1",
'host2': "pwdofhost2",
}

or

env.roledefs = {
'testserver': ['host1', 'host2'],
'realserver': ['host3', ]
}
env.passwords = {
'host1': "pwdofhost1",
'host2': "pwdofhost2",
'host3': "pwdofhost3", 
}

2. Parse it into map nesting according to the key, put Go to deploy

In addition, the command can also be solidified into a cmds list...

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