Fabric最常用的命令行工具是fab。当Fabric安装的时候，我们都能在环境变量中找到它。

主要内容

#1.基本使用方法
#2.命令行选项
#3.Per-task参数
##3.1 Per-task语法定义
##3.2 角色和主机 Roles and hosts

1.基本使用方法

最常见的使用方法，使用时没有任何选项(options)

$ fab task1 task2

上面命令会在fabfile定义的主机上执行task1，接着是task2。

另一种用法，估计就很少人会知道了，

$ fab [options] -- [shell command]

— 后面的[shell command]会使用Fabric的run命令来执行。如果我们在命令行上定义了主机，[shell command]相当于作为单行的匿名task来执行。

$ fab -H host1,host2,host3 -- uname -a

与执行下面文件

from fabric.api import run

def anonymous():
    run("uname -a")

的命令

$ fab -H host1,host2,host3 anonymous

是一样的效果。

测试：
[cc lang=”php”]
[root@fabserver fabric]# cat fabfile.py
from fabric.api import run

def anonymous():
run(“uname -a”)

[root@fabserver fabric]# fab -H host1,host2,host3 — uname -a
[host1] Executing task ‘‘
[host1] run: uname -a
[host1] out: Linux host1 2.6.32-431.el6.x86_64 #1 SMP Fri Nov 22 03:15:09 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
[host1] out:

[host2] Executing task ‘‘
[host2] run: uname -a
[host2] out: Linux host2 2.6.32-431.el6.x86_64 #1 SMP Fri Nov 22 03:15:09 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
[host2] out:

[host3] Executing task ‘‘
[host3] run: uname -a
[host3] out: Linux host3 2.6.32-431.el6.x86_64 #1 SMP Fri Nov 22 03:15:09 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
[host3] out:

Done.
Disconnecting from host2… done.
Disconnecting from host3… done.
Disconnecting from host1… done.

[root@fabserver fabric]# fab -H host1,host2,host3 anonymous
[host1] Executing task ‘anonymous’
[host1] run: uname -a
[host1] out: Linux host1 2.6.32-431.el6.x86_64 #1 SMP Fri Nov 22 03:15:09 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
[host1] out:

[host2] Executing task ‘anonymous’
[host2] run: uname -a
[host2] out: Linux host2 2.6.32-431.el6.x86_64 #1 SMP Fri Nov 22 03:15:09 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
[host2] out:

[host3] Executing task ‘anonymous’
[host3] run: uname -a
[host3] out: Linux host3 2.6.32-431.el6.x86_64 #1 SMP Fri Nov 22 03:15:09 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
[host3] out:

Done.
Disconnecting from host2… done.
Disconnecting from host3… done.
Disconnecting from host1… done.
[/cc]

2.命令行选项

fab命令的选项(options)基本上都可以对应上fabfile中的env变量。

如-H HOSTS, –hosts=HOSTS 有 env.hosts
[cc lang=”php”]
# fab –help
Usage: fab [options] [:arg1,arg2=val2,host=foo,hosts=’h1;h2′,…] …

Options:
-h, –help show this help message and exit
-d NAME, –display=NAME #显示命令[NAME]的细节信息
print detailed info about command NAME
-F FORMAT, –list-format=FORMAT #格式
formats –list, choices: short, normal, nested
-I, –initial-password-prompt
Force password prompt up-front
-l, –list #列出可以执行的命令
print list of possible commands and exit
–set=KEY=VALUE,… #设置env的key=value对
comma separated KEY=VALUE pairs to set Fab env vars
–shortlist alias for -F short –list
-V, –version show program’s version number and exit
-a, –no_agent don’t use the running SSH agent
-A, –forward-agent forward local agent to remote end
–abort-on-prompts abort instead of prompting (for password, host, etc)
-c PATH, –config=PATH
specify location of config file to use
–colorize-errors Color error output
-D, –disable-known-hosts
do not load user known_hosts file
-e, –eagerly-disconnect
disconnect from hosts as soon as possible
-f PATH, –fabfile=PATH #fabric python模块文件路径
python module file to import, e.g. ‘../other.py’
-g HOST, –gateway=HOST #网关
gateway host to connect through
–hide=LEVELS comma-separated list of output levels to hide
-H HOSTS, –hosts=HOSTS #主机定义，多个以逗号分开
comma-separated list of hosts to operate on
-i PATH path to SSH private key file. May be repeated.
-k, –no-keys don’t load private key files from ~/.ssh/
–keepalive=N enables a keepalive every N seconds
–linewise print line-by-line instead of byte-by-byte
-n M, –connection-attempts=M #连接尝试次数
make M attempts to connect before giving up
–no-pty do not use pseudo-terminal in run/sudo
-p PASSWORD, –password=PASSWORD #授权或sudo时使用的密码
password for use with authentication and/or sudo
-P, –parallel #并行执行
default to parallel execution method
–port=PORT SSH connection port #ssh端口
-r, –reject-unknown-hosts #主机不存在于SSH known_hosts文件中，就会中止连接
reject unknown hosts
–system-known-hosts=SYSTEM_KNOWN_HOSTS
load system known_hosts file before reading user
known_hosts
-R ROLES, –roles=ROLES #角色
comma-separated list of roles to operate on
-s SHELL, –shell=SHELL #远程执行命令的shell
specify a new shell, defaults to ‘/bin/bash -l -c’
–show=LEVELS comma-separated list of output levels to show
–skip-bad-hosts skip over hosts that can’t be reached
–ssh-config-path=PATH
Path to SSH config file
-t N, –timeout=N #ssh连接超时时间
set connection timeout to N seconds

-T N, –command-timeout=N #ssh远程命令执行超时时间
set remote command timeout to N seconds
-u USER, –user=USER #远程主机的用户名
username to use when connecting to remote hosts
-w, –warn-only warn, instead of abort, when commands fail
-x HOSTS, –exclude-hosts=HOSTS #哪些主机不需要执行命令
comma-separated list of hosts to exclude
-z INT, –pool-size=INT #并行执行时，并发线程数
number of concurrent processes to use in parallel mode
[/cc]
测试：

选项 -d
[cc lang=”php”]

[root@fabserver fabric]# cat fabfile.py
def hello(name=”world”):
print(“Hello %s!” % name)
[root@fabserver fabric]# fab -d hello
Displaying detailed information for task ‘hello’:

No docstring provided
Arguments: name=’world’
[/cc]
3.Per-task参数
3.1 Per-task语法定义
上面”2.命令行选项”提到的命令行选项是全局有效。如果不是变量又在其它地方覆盖命令行选项值的话，这些定义对所有task都是有效的。

我们可以针对每个task，定义不同的参数，这就是“per-task arguments”。

“per-task arguments”语法定义：

(1) 使用:分隔任务(task)和与参数(arguments)

(2) 使用,分隔不同的参数(arguments),参数需要反斜线()进行转义,如\,

(3) 使用=进行keyword arguments的赋值，或根据位置参数进行定义。同样需要使用反斜线进行转义。

例子：
[cc lang=”php”]
[root@fabserver fabric]# cat fabfile.py
def new_user(username, admin=’no’, comment=”No comment provided”):
print(“New User (%s): %s” % (username, comment))
pass
[root@fabserver fabric]# fab -l
Available commands:

new_user
[root@fabserver fabric]#

#仅定义username
[root@fabserver fabric]# fab new_user:myusername
New User (myusername): No comment provided

Done.
[root@fabserver fabric]# fab new_user:username=myusername
New User (myusername): No comment provided

Done.

#使用位置参数
[root@fabserver fabric]# fab new_user:myusername,yes
New User (myusername): No comment provided

Done.

#混合使用
[root@fabserver fabric]# fab new_user:myusername,admin=yes
New User (myusername): No comment provided

Done.
#使用转义
[root@fabserver fabric]# fab new_user:myusername,admin=no,comment=’Gary\, new developer (starts Monday)’
New User (myusername): Gary, new developer (starts Monday)

Done.
[/cc]
3.2 角色和主机 Roles and hosts
常用的参数：host, hosts, role and roles

注意：hosts的主机是以;隔开。
[cc lang=”php”]
[root@fabserver fabric]# fab new_user:myusername,hosts=”host1;host2″
[host1] Executing task ‘new_user’
New User (myusername): No comment provided
[host2] Executing task ‘new_user’
New User (myusername): No comment provided

Done.
[/cc]

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