一、背景
因为需要上线灰度发布，只要nginx接收到头部为：
wx_unionid:123456
就会跳转到另外一个url，比如：
127.0.0.1:8080
通过配置nginx 匹配请求头wx_unionid 来转发到灰度环境。
核心：客户端自定义的http header，在nginx的配置文件里能直接读取到。
条件：header必须用减号“-”分隔单词，nginx里面会转换为对应的下划线“_”连接的小写单词。
二、修改Nginx配置
安装nginx
apt-get install -y nginx
编辑主页
cd /etc/nginx/sites-enabled
vim home.conf
内容如下：
upstream wx { server 127.0.0.1:8080; } server { listen 8008; server_name localhost; root html; index index.html; charset utf-8; underscores_in_headers on; location / { #测试header转发 if ($http_wx_unionid = "123456") { proxy_pass http://wx; } } }
参数配置说明
underscores_in_headers on：nginx是支持读取非nginx标准的用户自定义header的，但是需要在http或者server下开启header的下划线支持:
比如我们自定义header为wx_unionid,获取该header时需要这样:$http_wx_unionid(一律采用小写，而且前面多了个http_)
如果需要把自定义header传递到下一个nginx：
1.如果是在nginx中自定义采用proxy_set_header X_CUSTOM_HEADER $http_host;
2.如果是在用户请求时自定义的header，例如curl –head -H “X_CUSTOM_HEADER: foo” http://domain.com/api/test，则需要通过proxy_pass_header X_CUSTOM_HEADER来传递
编辑调整页
vim wx.conf
内容如下：
server { listen 8080; server_name localhost; root /var/www/html; index wx.html; location / { try_files $uri $uri/ =404; } }
增加测试页面
vim /var/www/html/wx.html
内容如下：
<h1>微信小程序测试平台</h1>
三、测试结果
加自定义头部
root@ubuntu:~# curl -v -H 'wx_unionid:123456' 127.0.0.1:8008 * Rebuilt URL to: 127.0.0.1:8008/ * Trying 127.0.0.1... * Connected to 127.0.0.1 (127.0.0.1) port 8008 (#0) > GET / HTTP/1.1 > Host: 127.0.0.1:8008 > User-Agent: curl/7.47.0 > Accept: */* > wx_unionid:123456 > < HTTP/1.1 200 OK < Server: nginx/1.10.3 (Ubuntu) < Date: Mon, 29 Jul 2019 07:49:46 GMT < Content-Type: text/html; charset=utf-8 < Content-Length: 37 < Connection: keep-alive < Last-Modified: Mon, 29 Jul 2019 06:23:49 GMT < ETag: "5d3e90f5-25" < Accept-Ranges: bytes < <h1>微信小程序测试平台</h1> * Connection #0 to host 127.0.0.1 left intact
不加头部
root@ubuntu:~# curl -v 127.0.0.1:8008 * Rebuilt URL to: 127.0.0.1:8008/ * Trying 127.0.0.1... * Connected to 127.0.0.1 (127.0.0.1) port 8008 (#0) > GET / HTTP/1.1 > Host: 127.0.0.1:8008 > User-Agent: curl/7.47.0 > Accept: */* > < HTTP/1.1 200 OK < Server: nginx/1.10.3 (Ubuntu) < Date: Mon, 29 Jul 2019 07:50:13 GMT < Content-Type: text/html; charset=utf-8 < Content-Length: 612 < Last-Modified: Tue, 31 Jan 2017 15:01:11 GMT < Connection: keep-alive < ETag: "5890a6b7-264" < Accept-Ranges: bytes < <!DOCTYPE html> <html> <head> <title>Welcome to nginx!</title> <style> body { 35em; margin: 0 auto; font-family: Tahoma, Verdana, Arial, sans-serif; } </style> </head> <body> <h1>Welcome to nginx!</h1> <p>If you see this page, the nginx web server is successfully installed and working. Further configuration is required.</p> <p>For online documentation and support please refer to <a href="http://nginx.org/">nginx.org</a>.<br/> Commercial support is available at <a href="http://nginx.com/">nginx.com</a>.</p> <p><em>Thank you for using nginx.</em></p> </body> </html> * Connection #0 to host 127.0.0.1 left intact
四、匹配多条件
现在又多了一个需求，需要对客户端ip为：192.168.0.45，同时也增加自定义头部wx_unionid:123456，才会转发，否则不做转发。
nginx的配置中不支持if条件的逻辑与&& 逻辑或|| 运算 ，而且不支持if的嵌套语法，否则会报下面的错误：nginx: [emerg] invalid condition。
我们可以用变量的方式来间接实现。
要实现的语句：
if ($remote_addr ~* "192.168.0.45" && $http_wx_unionid = "123456"){ proxy_pass http://wx; }
如果按照这样来配置，就会报nginx: [emerg] invalid condition错误。
如下：
nginx: [emerg] invalid condition "$http_wx_unionid" in /etc/nginx/sites-enabled/home.conf:16 nginx: configuration file /etc/nginx/nginx.conf test failed
可以这么来实现，如下所示：
upstream wx { server 127.0.0.1:8080; } server { listen 8008; server_name localhost; root html; index index.html; charset utf-8; underscores_in_headers on; location / { #测试header转发 # 标志位 set $flag 0; if ($remote_addr ~* "192.168.0.45"){ # 末尾追加1，此时$flag=01 set $flag "${flag}1"; } if ($http_wx_unionid = "123456"){ # 末尾追加1，此时$flag=011 set $flag "${flag}1"; } # 当为011时，表示条件都匹配 if ($flag = "011") { proxy_pass http://wx; } } }
重新加载配置
nginx -s reload
再次使用本机测试，增加头部
root@ubuntu:~# curl -v -H 'wx_unionid:123456' 127.0.0.1:8008 * Rebuilt URL to: 127.0.0.1:8008/ * Trying 127.0.0.1... * Connected to 127.0.0.1 (127.0.0.1) port 8008 (#0) > GET / HTTP/1.1 > Host: 127.0.0.1:8008 > User-Agent: curl/7.47.0 > Accept: */* > wx_unionid:123456 > < HTTP/1.1 200 OK < Server: nginx/1.10.3 (Ubuntu) < Date: Mon, 29 Jul 2019 08:01:30 GMT < Content-Type: text/html; charset=utf-8 < Content-Length: 612 < Last-Modified: Tue, 31 Jan 2017 15:01:11 GMT < Connection: keep-alive < ETag: "5890a6b7-264" < Accept-Ranges: bytes < <!DOCTYPE html> <html> <head> <title>Welcome to nginx!</title> <style> body { 35em; margin: 0 auto; font-family: Tahoma, Verdana, Arial, sans-serif; } </style> </head> <body> <h1>Welcome to nginx!</h1> <p>If you see this page, the nginx web server is successfully installed and working. Further configuration is required.</p> <p>For online documentation and support please refer to <a href="http://nginx.org/">nginx.org</a>.<br/> Commercial support is available at <a href="http://nginx.com/">nginx.com</a>.</p> <p><em>Thank you for using nginx.</em></p> </body> </html> * Connection #0 to host 127.0.0.1 left intact
登录到192.168.0.45，增加头部测试
root@docker-reg:~# curl -v -H 'wx_unionid:123456' 192.168.0.162:8008 * Rebuilt URL to: 192.168.0.162:8008/ * Trying 192.168.0.162... * Connected to 192.168.0.162 (192.168.0.162) port 8008 (#0) > GET / HTTP/1.1 > Host: 192.168.0.162:8008 > User-Agent: curl/7.47.0 > Accept: */* > wx_unionid:123456 > < HTTP/1.1 200 OK < Server: nginx/1.10.3 (Ubuntu) < Date: Mon, 29 Jul 2019 08:02:01 GMT < Content-Type: text/html; charset=utf-8 < Content-Length: 37 < Connection: keep-alive < Last-Modified: Mon, 29 Jul 2019 06:23:49 GMT < ETag: "5d3e90f5-25" < Accept-Ranges: bytes < <h1>微信小程序测试平台</h1> * Connection #0 to host 192.168.0.162 left intact
本文参考链接：
https://blog.csdn.net/qq_25934401/article/details/83113520
https://blog.csdn.net/lai0yuan/article/details/80784058
https://blog.csdn.net/woshizhangliang999/article/details/51701327