Python fabric implements remote operation and deployment examples

Recently, I have taken over more and more things. The work of release and operation and maintenance 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 ABCDE5 respectively Each machine is restarted one by one (8-10 minutes) = 13-15 minutes. The frustrating thing is that each operation is the same and the command is the same. The terrible thing is that on multiple machines, it is difficult to do it with one script on this machine. The main time was wasted on ssh, typing commands, and writing them into scripts, which can be executed with one click. It took two minutes to look at the execution results until I discovered that fabric can solidify commands for automated deployment or multi-machine operations. Into a script is very similar to some operation and maintenance tools. The main reason for using it is that it is simple, easy to use and easy to use. Of course, you can also combine various shell commands. The difference between ancient artifacts and modern weapons

Environment Configuration

Install the corresponding package on the local machine and the target machine (note, both must be present)

sudo easy_install fabric

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

After the installation is completed, you can check whether the installation is successful

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

After the installation is completed, you can browse the official documentation

Then, you can get started

hello world

First perform simple operations on this machine and have a preliminary understanding. The source of the example is from 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 when executing

[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.

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 needs to be repeated every day. Let us see how to use fabric to achieve one-click completion: (It is actually practical Shell scripts can be done directly, but the advantage of fab is not here. Here we mainly prepare for local + remote operations. 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…..

Mix and match to integrate remote operations Operation

At this time, assume that you want to go to the project directory corresponding to machine A's /home/ken/project 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:

[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 requiring password input will pop up when executing to the corresponding machine

Multiple server mashup

To operate multiple servers, multiple hosts need to be configured

#!/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 the color, which is more eye-catching and convenient when viewing the operation result information

from fabric.colors import *
def show():
    print green('success')
    print red('fail')
    print yellow('yellow')
#fab -f color.py show

2. Errors and exceptions

About error handling

By default, a set of commands will not continue to execute after the previous command fails to execute

After failure Different processing can also be performed. The document

is not used at the moment. Please read it if you use it later

3. Password management

See the document

A better way to manage passwords. I’m a bit unsophisticated and haven’t gotten through it. The main reason is that the server list changes frequently. My solution is:

1. Host, user, port, password configuration list, all written in A file

or directly 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 into map nesting based on key , put it in deploy

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

For more python fabric implementation examples of remote operation and deployment related articles, please pay attention to the PHP Chinese website!