ngx_http_service_module

Nginx service processing module

Prerequisites

• Linux Platform
• Nginx version is not lower than 1.9.11
• Installed tools for Nginx compilation

Module Features

• Service request/response messages are all in json format. The cJSON library is compiled by default. Business developers can use it to parse/package packets, and of course they can also use other json parsing libraries (see example/third_test section)
• By implementing a specific interface, compile the service into a dynamic library and load it into Nginx

advantage

• High performance , using Nginx's multi-process model to process business, and business developers can also use multi-threading in the implemented interface according to specific scenarios to further improve performance, and can also scale horizontally through load balancing.
• Strong , when the service crashes, Nginx will re-start the work process to ensure that the business does not stop processing
• Service smooth restart/upgrade . With the help of Nginx's smooth restart/upgrade function, service restart/upgrade can be elegantly restarted/upgrade.

Build

1. Download Nginx source code

 # 这里以 nginx-1.24.0 为例, 也可以根据自己情况下载其他版本的 nginx 源码
wget http://nginx.org/download/nginx-1.24.0.tar.gz

2. Decompress and enter the Nginx source code directory

tar -zxvf nginx-1.24.0.tar.gz
cd nginx-1.24.0

3. Pull the code of this project

 # 这里拉取到 nginx 源码的目录下, 也可以根据情况拉取到其他目录
git clone https://github.com/xukeawsl/ngx_http_service_module.git

4. Add the module to nginx and install it

 # 如果你将项目代码放在其他路径, 则需要修改这里的模块路径
./configure --add-module=ngx_http_service_module
make
make install

Configuration commands

1. module_path (can only be configured in http block)

• This command configures the path to which the dynamic library belongs. If it is not configured, install the default search path search
• The first parameter is the path, followed by the dynamic library file name (full name)

 module_path {
    / path/to /dir1    module1.so;
    / path/to /dir2    module2.so  module3.so;
}

2. module_dependency (can only be configured in http block)

• This configuration sets the dependencies between dynamic libraries
• The first parameter is the dynamic library that is dependent, followed by the dynamic library it depends on

 module_dependency {
    module1. so     module2.so;
    module3. so     module2.so  libjsoncpp.so;
}

3. service (can only be configured in http block)

• Services provided by this configuration setting module
• The first parameter is the dynamic library file name, followed by the service name provided for the dynamic library (case sensitive)
• Service name needs to be globally unique

 service {
    module1. so    srv_echo  srv_datetime;
    module2. so    srv_sayHello;
    module3. so    srv_getSum;
}

4. service_mode (http, server, location blocks can all be configured)

• Used to enable module functions, the unenabled parts will not be processed for service
• Not enabled by default, the following example is enabled globally on the specified server, but the routing request for /test is not processed

 http {

    server {
        sevice_mode on;

        location /test {
            service_mode off;
        }
    }
}

Service interface development

• Users need to include the ngx_http_service_interface.h interface file in the project

 // 接口形如下面的函数

#include "ngx_http_service_interface.h"
#include "cJSON.h"

void srv_sayHello ( const ngx_request_t * rqst , ngx_request_t * resp )
{
    // do something...
}

• Request/response structure

 // 请求结构只包含一个 const char * 指针指向 json 请求字符串
struct ngx_json_request_s {
    const char * data ;
};

// 响应结构包含一个 char * 指针指向 json 响应字符串和一个回调函数用于释放响应字符串的内存
// 因为对于 c++ 实现的服务可能使用 new 来分配内存, 那就需要指定正确的内存释放方式
struct ngx_json_response_s {
    char * data ;
    void ( * release )( void * );
};

Service Call Rules

• The request method requires POST
• Specify the service to be called by the value of the http header Service-Name
• Content-Type must be of type json
• As follows, call the srv_sayHello service

curl -X POST " http://localhost/service_test " 
-H ' Content-Type: application/json ' 
-H ' Service-Name: srv_sayHello ' 
-d ' {"data": "xxxx"} '