程序员瑞士军刀之 Fabric

程序员瑞士军刀之 Fabric

Fabric是一个Python库, 也是一个命令行工具, 通过 SSH 来做应用程序的部署和系统管理任务

它可以执行本地的远程的系统命令, 上传下载文件, 以及其他能用Python编程完成的任务

其实它一个工具框架, 执行一个默认的 python 文件 fabfile.py

简单写个小例子

$vi fabfile

from fabric.api import *

env.hosts = ['10.224.64.106']
env.user   = "root"
env.password = "pass"

def freedisk(param='-h'):
cmd = 'df ' + param
run(cmd)

def listfile(folder='~'):
cmd = 'ls -l ' + folder
run(cmd)

def pullcodes(folder='/workspace/cpp/snippets'):
with cd(folder):
run("git pull origin master")

# 察看远程服务器上的磁盘剩余空间
$ fab listfile:folder=/home/walter

为安全起见, 不用在文件中存放密码, 在命令行提示输入

$ fab -u root -I -H 10.224.64.106 freedisk

更好的做法是把本机私钥预先拷贝到目标服务器上, 这样就不用输入密码了

1. 在本机上生成公钥  ~/.ssh/id_rsa.pub
ssh-keygen -t rsa

2. 拷贝此公钥到目标服务器 10.224.64.106 上
scp id_rs.pub root@10.224.64.106:/root

3. 目标服务器 10.224.64.106 上
cat id_rsa.pub >> ~/.ssh/authorized_keys
chmod 700 ~/.ssh/authorized_keys

常用方法

run (fabric.operations.run)

sudo (fabric.operations.sudo)

local (fabric.operations.local)

get (fabric.operations.get)

put (fabric.operations.put)

prompt (fabric.operations.prompt)

reboot (fabric.operations.reboot)

常用函数

cd (fabric.context_managers.cd)

lcd (fabric.context_managers.lcd)

path (fabric.context_managers.path)

settings (fabric.context_managers.settings)

prefix (fabric.context_managers.prefix)

例子:批量上传下载文件

from fabric.api import *
from fabric.context_managers import *
from fabric.contrib.console import confirm

env.user='root'
env.hosts=['10.224.64.106']
env.passwords = {
'root@10.224.64.106:22': 'password'
}

local_dir='/workspace/cpp/codelab'
remote_dir = '/home/walter/cpp/codelab'
file_list = [
'src/FileUtils.cpp',
'src/FileUtils.h',
'src/Makefile.am',
'src/StringUtils.cpp'
]

@task
def hostinfo():
run('uname -s')

@task
def upload(): #upload file task
with cd(remote_dir) :
for filename in file_list:
local_file  = local_dir  + "/" + filename
remote_file = remote_dir + "/" + filename
#print local_file, " to ", remote_file
with settings(warn_only=True):    #when upload error,continue
result = put(local_file, remote_file)
if result.failed and not confirm("put file failed,Continue[Y/N]?"):
abort("Aborting file put task!")

@task
def download(): #upload file task
with cd(remote_dir) :
for filename in file_list:
local_file  = local_dir  + "/" + filename
remote_file = remote_dir + "/" + filename
#print local_file, " to ", remote_file
with settings(warn_only=True):    #when upload error,continue
result = get(remote_file,local_file)
if result.failed and not confirm("put file failed,Continue[Y/N]?"):
abort("Aborting file put task!")

高阶用法

设置角色role来指定远程的服务器范围

或者直接用字典由输入参数指定, 例如:

# usage:
# fab localpull:rtc
# fab checkfiles:hf2
from fabric.api import *
from fabric.context_managers import *
from fabric.contrib.console import confirm

env.user = 'root'
env.roledefs = {
'qa': ['root@10.224.57.202:22'],
'dev': ['root@10.224.64.106:22']
}

env.passwords = {
'root@10.224.57.202:22': 'pass',
'root@10.224.64.106:22': 'pass',
'root@10.224.64.107:22': 'pass'
}

@roles('dev')
@task
def localpull(app='web'):
if app == 'web':
code_dir = '/workspace/walter/hfweb'
with lcd(code_dir):
local("git pull origin master")
elif app == 'rtc':
code_dir = '/workspace/walter/hfrtc'
with lcd(code_dir):
local("git pull origin master")
local("git branch -l")

test_servers = {'hf1':['root@10.224.64.46:22'],
'hf2':['root@10.224.64.106:22'],
'hf3':['root@10.224.64.107:22']}

@task
def listfiles():
run("ls -l")

@task
def checkfiles(target_env='hf2'):
execute("listfiles", hosts=test_servers[target_env])

FAQ

问题: fab put error: paramiko.ssh_exception.SSHException: Channel closed

解决方法:

编辑 /etc/ssh/sshd_config:

vi /etc/ssh/sshd_config

加上一行

Subsystem      sftp    internal-sftp

Port 22
Protocol 2
LogLevel INFO
X11Forwarding no
MaxAuthTries 4
IgnoreRhosts yes
HostbasedAuthentication no
PermitRootLogin yes
PermitEmptyPasswords no
PermitUserEnvironment no
Ciphers aes128-ctr,aes192-ctr,aes256-ctr
ClientAliveInterval 600
Banner /etc/issue
#for sftp
Subsystem      sftp    internal-sftp

保存并重启 SSH server:

service sshd restart

参考链接

Fabric site

Fabric Tutorial

Fabric options