1.拦截方式
强制进行code review，有两种方式：

将仓库托管在phabricator上，通过herald的方式来进行
在代码托管服务器上增加hook来实现
由于我们的代码托管到gitlab上，所有我们采用第二种方式进行code review

2.gitlab server端添加hook

gitlab添加hook的方式有两种：
    局部添加，作用于当前这个仓库
    全局添加，作用于全部仓库 

2.1 局部配置

cd /srv/gitlab/data/git-data/repositories/root/pipeline-example-go.git ###gitlab serve端进入到具体的仓库路径下
mkdir custom_hooks  #创建自定义hook目录
touch pre-receive   #创建pre-receive 文件
chmod 755 pre-receive #修改文件权限
pre-receive 钩子，在有人用 git push 向仓库推送代码时被执行，其内容如下：
#!/usr/bin/env python
import sys,os
import fileinput
import re
import json
import requests
def has_been_reviewed(start_commit, end_commit):
    cmd = 'git rev-list %s...%s' % (start_commit, end_commit,)
    Flag = False
    commits = os.popen(cmd).readlines()
    pattern = re.compile(r'Differential Revision: (.*)')
    for commit in commits:
        cmd = 'git rev-list --format=' + '%s%b ' + '--max-count=1 %s' % commit
        res  = os.popen(cmd).readlines()[-2]
        match_str = pattern.match(res)
        if not  match_str:
            print("Please use 'arc diff' to commit")
            continue
        http_url = match_str.group(1)
        url = "https://xxx/api/differential.query?api.token=*****"
        info = json.loads(requests.get(url).text)
        for i in info['result']:
            if i['uri'] != http_url: continue
            if i['statusName'] == 'Accepted':
                Flag = True
            else:
                print("Current Status: %s, Need Review and Accepted" % i['statusName'])
            break
    if Flag:
        sys.exit(0)
    else:
        sys.exit(1)

if __name__  == "__main__":
    for line in fileinput.input():
        args = line.split(' ')
    start_commit = args[0]
    end_commit = args[1]
    if start_commit != '0000000000000000000000000000000000000000' and  end_commit != '0000000000000000000000000000000000000000':
        has_been_reviewed(start_commit, end_commit)
代码解释：

1.git rev-list --format=%s%b  --max-count=1  ${commit_id} 
#获取git commit 的提交信息，默认git commit -m 后的信息，但是使用arc diff 之后，arc diff的信息会覆盖之前的git commit 的内容
2.requests.get("https://***/api/differential.query?api.token=***")
 #通过ph的api接口获取到所有的differential 信息，其中token 可通过https://***/conduit/login/ 获取
3.#获取differential的信息之后，选取uri为当前提交的revision，若状态Accepted，表示代码review通过，退出程序，返回状态码0，表示不拦截
4.#若获取状态不为Accepted，则返回状态码非0，表示执行失败，拦截git push请求

  ***

2.2 全局配置

1.开启gitlab的自定义hook参数
vim  /etc/gitlab/gitlab.rb   #配置如下 
gitlab_shell['custom_hooks_dir'] = "/opt/gitlab/embedded/service/gitlab-shell/hooks/custom_hooks" 
 #取消这行注释，默认是注释
2.mkdir -p  /opt/gitlab/embedded/service/gitlab-shell/hooks/custom_hooks/pre-receive.d  # 创建目录
3.touch /opt/gitlab/embedded/service/gitlab-shell/hooks/custom_hooks/pre-receive.d/pre-receive  #创建文件pre-receive 
4.chmod 755 /opt/gitlab/embedded/service/gitlab-shell/hooks/custom_hooks/pre-receive.d/pre-receive 
5.pre-receive #文件内容如上
6.gitlab-ctl reconfigure  #重新加载gitlab的配置, 使配置生效

Ref：

   [1]  https://github.com/geeeeeeeeek/git-recipes/wiki

   [2] https://www.cnblogs.com/zhangshiwen/p/7747864.html