用svn的hooks实现自动更新web项目的远程测试站点

    Web项目的开发过程中我们经常会有这样的需求：当我们向svn服务器commit修改的代码后，能够即时的体现在测试站点上。其实svn已经为我们提供了这样的接口，那就是hooks。

    当我们创建一个svn repository之后，我们可以看到它的repository结构，有一个hooks文件夹，里面有一些.tmpl文件。这是一些示例脚本，我们可以用这些示例脚本作为范本来修改满足自己的项目需求。

下面描述一下我们的项目需求和实现：

    我们的svn代码服务器和web测试服务器是两个不同的服务器，其中svn代码服务器是ubuntu-server系统，web测试服务器是centos。我们要在svn代码服务器收到开发人员commit的变更之后即时的通知（通过ssh连接到测试服务器）web测试服务器使之自动从svn代码服务器获取svn变更（svn update）。所以我们创建了一个post-commit的hook。这个hook脚本使用了expect，在ubuntu中可以通过"sudo apt-get install expect"来安装。

参考了这篇博文，利用博文中提供的脚本，我做了一些小的修改，最后是下面这样的：

#!/usr/bin/expect -f
## AUTHOR: Meitar Moscovitz
# DATE : Thu Jun 21 16:32:42 EDT 2007#

set HOST my.web.server #服务器地址
set USER someuser      #用户名
set PASS xxx           #密码

# the working copy we're going to update
set WC /path/to/working/copy   #测试web的svn副本路径
set LOG /path/to/log/file      #日志输出（可以查看到最后一次svn update的revision）

# the path to the svn executable on the remote web server
set SVNBIN /usr/bin/svn

# our network is slow, set a long timeout
set timeout 30

##### DO NOT EDIT PAST THIS LINE! #####
# POST-COMMIT HOOK#
# The post-commit hook is invoked after a commit.  Subversion runs
# this hook by invoking a program (script, executable, binary, etc.)
# named 'post-commit' (this file) with the
# following ordered arguments:#
#   [1] REPOS-PATH   (the path to this repository)
#   [2] REV          (the number of the revision just committed)#
# Note that Subversion does not provide this program with an environment
# of any kind. That means this program lacks a current working directory,
# a home directory, a $PATH, and so on.

set REPOS [lindex $argv 0]
set REV [lindex $argv 1]

# Define error codes
set E_NO_SSH     1 ;# can't find a usable SSH on our system
set E_NO_CONNECT 2 ;# failure to connect to remote server (timed out)
set E_WRONG_PASS 3 ;# password provided does not work
set E_UNKNOWN   25 ;# unexpected failure

# find the SSH binary on our system
if {[file executable /usr/bin/ssh]} {
set SSHBIN /usr/bin/ssh
} elseif {[file executable /usr/local/bin/ssh]} {
set SSHBIN /usr/local/bin/ssh
} else {
send_error "Can't find a usable SSH on this system.\n"
exit $E_NO_SSH
}

spawn $SSHBIN $USER@$HOST "$SVNBIN update -r HEAD --force $WC >> $LOG"

expect {
    "continue connecting (yes/no)? " { send "yes\r"; exp_continue; }
    -nocase "password:" { send "$PASS\r"; }
    timeout {
        send_error "\nWe have timed out after $timeout seconds while trying to connect to $HOST!\n";
        exit $E_NO_CONNECT;
    }
}

expect {
        -nocase "password:" { ;# if we are asked for the password again, then we have provided the wrong password
                send_error "\nCan not log in to $HOST because the password provided for user $USER has been rejected.\n";
                exit $E_WRONG_PASS;
        }
        -re "revision (\[0-9]+)." {
                if {$REV == $expect_out(1,string)} {
                        send_user "\nSuccessfully updated $WC on $HOST to revision $REV.\n"
                } else {
                        send_user "\nUpdated repository to revision $expect_out(1,string), but svn reports that we are at revision number $REV.\n"
                        send_error "CAUTION: Repository updated to revision $expect_out(1,string), but committed revision $REV.\n"
                }
        }
#将下面几行注释掉的原因是因为我发现#其实这个hook脚本已经成功使web测试服务器更新(svn update)了working copy但是还是会抛出这个错误！
#而且这个错误也会在svn客户端（比如：TortoiseSVN）的commit动作的最后出现！
#       default {
#               send_error "An unexpected error has occured. The process at spawn ID $spawn_id has produced the following output:\n"
#               send_error $expect_out(buffer)
#               exit $E_UNKNOWN
#       }
}

好了，另外要注意一下这个post-commit脚本文件要具备关联用户（比如：www-data）的可执行权限。可以直接输入"./post-commit"测试一下结果。 

文章来自：http://hi.baidu.com/devylee/item/247db2d0aead56362b35c7f1