git、nagios 和 hooks、损坏的 git repo

Question

背景

我们正在使用 nagios 来监控我们的基础设施。我们目前没有版本控制下的 nagios 配置，我们有两个人管理 nagios 配置。因此，我正在努力将我们的 nagios 配置放入中央 git 存储库中，使用一些钩子进行语法检查，然后如果配置看起来不错，则使它们“处于活动状态”。我正在使用这个人的帖子作为起点。

我试图实现的一般工作流程是：

1. 编辑 nagios 配置的本地 git repo。添加编辑过的文件，在本地提交。
2. git push origin master 到远程仓库。
3. Push 被 pre-receive hook 拦截，它获取文件，将它们移动到服务器上的临时目录，并通过 nagios 语法检查器运行它们。
4. 如果语法检查器通过，则接受推送，然后使用 post-commit hookgit pull将新代码放入 live nagios 配置目录中，然后重新启动 nagios。
5. 如果语法检查器失败，则拒绝推送，向用户显示 nagios 语法错误。

但是，当我由于 nagios 配置中的语法错误而拒绝 git push 时，我遇到了一个奇怪的行为。我期望发生的是，如果我拒绝钩子，则尝试推送应该使存储库保持原样，原样。不过，情况似乎并非如此。以下是我所看到的详细信息：

问题

我在本地编辑 nagios 配置，故意包含一个语法错误，添加，然后在本地提交：

host:nagios erik$ vi nagios.cfg
host:nagios erik$ git add nagios.cfg
host:nagios erik$ git commit -m "syntax error"
[master da71aed] syntax error
 1 files changed, 1 insertions(+), 0 deletions(-)

现在我将这些更改推送到主存储库。由于语法错误，这将被拒绝：

host:nagios erik$ git push origin master
Counting objects: 5, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (2/2), done.
Writing objects: 100% (3/3), 12.74 KiB, done.
Total 3 (delta 1), reused 2 (delta 1)
remote: Previous HEAD position was 3ddc880... removed syntax error
remote: HEAD is now at da71aed... syntax error
remote: Nagios Config Check Exit Status: 254
remote: Your configs did not parse correctly, there was an error. Output follows.
remote:
remote: Nagios Core 3.2.3
remote: Copyright (c) 2009-2010 Nagios Core Development Team and Community Contributors
remote: Copyright (c) 1999-2009 Ethan Galstad
remote: Last Modified: 10-03-2010
remote: License: GPL
remote:
remote: Website: http://www.nagios.org
remote: Reading configuration data...
remote: Error in configuration file '/tmp/nagiosworkdir/nagios.cfg' - Line 23 (NULL value)
remote:    Error processing main config file!
remote:
remote:
remote:
remote: ***> One or more problems was encountered while processing the config files...
remote:
remote:      Check your configuration file(s) to ensure that they contain valid
remote:      directives and data defintions.  If you are upgrading from a previous
remote:      version of Nagios, you should be aware that some variables/definitions
remote:      may have been removed or modified in this version.  Make sure to read
remote:      the HTML documentation regarding the config files, as well as the
remote:      'Whats New' section to find out what has changed.
remote:
To git@remote-server.example.com:nagios
 ! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'git@remote-server.example.com:nagios'

这不应该触及远程仓库，但确实如此。如果我更改到另一个本地临时目录并尝试克隆存储库，我会得到：

host:temp erik$ git clone git@remote-server.example.com:nagios
Cloning into nagios...
remote: Counting objects: 30, done.
remote: Compressing objects: 100% (29/29), done.
remote: Total 30 (delta 12), reused 0 (delta 0)
Receiving objects: 100% (30/30), 29.81 KiB, done.
Resolving deltas: 100% (12/12), done.
error: Trying to write ref HEAD with nonexistant object da71aedfde2e0469288acd9e45bb8b57a6e5a7b3
fatal: Cannot update the ref 'HEAD'.

现在我回到原来的工作目录，修复语法错误，添加、提交和推送：

host:nagios erik$ vi nagios.cfg
host:nagios erik$ git add nagios.cfg
host:nagios erik$ git commit -m "removing syntax error, push should succeed this time"
[master f147ded] removing syntax error, push should succeed this time
 1 files changed, 0 insertions(+), 2 deletions(-)
host:nagios erik$ git push origin master
Counting objects: 6, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (4/4), done.
Writing objects: 100% (4/4), 487 bytes, done.
Total 4 (delta 2), reused 0 (delta 0)
remote: Previous HEAD position was 4c80d45... syntax error
remote: HEAD is now at f147ded... removing syntax error, push should succeed this time
remote: Nagios Config Check Exit Status: 0
remote: Your configs look good and parsed correctly.
To git@remote-server.example.com:nagios
   3ddc880..f147ded  master -> master

此时，存储库很好，我可以切换到临时目录并再次克隆存储库：

host:temp erik$ git clone git@remote-server.example.com:nagios
Cloning into nagios...
remote: Counting objects: 34, done.
remote: Compressing objects: 100% (33/33), done.
remote: Total 34 (delta 14), reused 0 (delta 0)
Receiving objects: 100% (34/34), 30.22 KiB, done.
Resolving deltas: 100% (14/14), done.

这是我正在使用的预接收钩子。

我在客户端使用 git v1.7.5.4，在服务器上使用 v1.7.2.3。

那么，问题是：当我拒绝推送时，为什么存储库会处于不一致的状态？我的 git hook 有什么问题，或者我对 git 的理解不够？

Answer 1

你正在做的：

export GIT_WORK_TREE=/tmp/nagiosworkdir
/usr/bin/git checkout -f $NEW_SHA1

在你的钩子里。虽然它没有触及您通常的工作副本，但它正在更新 git-dir 中的HEAD引用（特别是引用），如您的错误所示：

...
remote: HEAD is now at da71aed... syntax error
...

您的钩子正在exit 1拒绝更新，但它不会HEAD在失败后（重新）重置引用。

我认为您需要像这样更新钩子中的故障分支：

...
if [ "$NAGIOS_CHECK_STATUS" -ne 0 ]
   then
   echo "Your configs did not parse correctly, there was an error. Output follows."
   cat $GIT_WORK_TREE/check.out
   /usr/bin/git reset --hard $OLD_SHA1    # <-- Add This
   exit 1
else
   ...