Development

Overview

This document explains how to get started to develop the apisix-java-plugin-runner.

Prerequisites

• JDK 11
• APISIX 2.10.x
• Clone the apisix-java-plugin-runner project.
• Refer to Debug to build the debug environment.

Install

cd /path/to/apisix-java-plugin-runner
./mvnw install

Write Filter

Refer to the code in the sample to learn how to extend PluginFilter, define the order, rewrite requests and stop requests.

Code Location

You need to put the code in runner-plugin so that the apisix-java-plugin-runner.jar will contain the filter implementation class you wrote when you package it.

The order of filter execution

The order of execution of the filter in the runner is determined by the index of the conf array in the ext-plugin-pre-req or ext-plugin-post-req configuration.

The name of filter execution

The requests go through filters that are dynamically configured on APISIX. For example, if the following configuration is done on APISIX

curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "uri":"/hello",
    "plugins":{
        "ext-plugin-pre-req":{
            "conf":[
                {
                    "name":"FooFilter",
                    "value":"bar"
                }
            ]
        }
    },
    "upstream":{
        "nodes":{
            "127.0.0.1:1980":1
        },
        "type":"roundrobin"
    }
}'

apisix-java-plugin-runner will look for implementation classes named FooFilter, and the name of each filter's implementation class is the return value of its overridden function public String name().

The functions must be implemented of filter execution

• String name();

  description: return the name of plugin filter

  code example:

    @Override
    public String name() {
        return "FooFilter";
    }

• void filter(HttpRequest request, HttpResponse response, PluginFilterChain chain);

  description: implementing custom business logic

  code example:

    @Override
    public void filter(HttpRequest request, HttpResponse response, PluginFilterChain chain) {
        // get conf of current filter
        String configStr = request.getConfig(this);
        Gson gson = new Gson();
        Map<String, Object> conf = new HashMap<>();
        // convert according to the actual configured conf type
        conf = gson.fromJson(configStr, conf.getClass());
  
        // get extra info
        String remoteAddr = request.getVars("remote_addr");
        String serverPort = request.getVars("server_port");
        String body = request.getBody();
  
        chain.filter(request, response);
    }

• List<String> requiredVars();

  description: declare in advance the nginx variables you want to use in the current filter

  code example:

    @Override
    public List<String> requiredVars() {
        List<String> vars = new ArrayList<>();
        vars.add("remote_addr");
        vars.add("server_port");
        return vars;
    }

• Boolean requiredBody();

  description: whether the request body is required in the current filter, true means yes.

  code example:

    @Override
    public Boolean requiredBody() {
        return true;
    }

Rewrite Request

If you perform the following function call in the filter chain of the implementation class

• request.setPath()
• request.setHeader()
• request.setArg()

this means to rewrit the current request, the upstream server will receive the relevant parameters rewritten here.

Stop Request

If you perform the following function call in the filter chain of the implementation class

• response.setStatusCode()
• response.setHeader()
• response.setBody()

this means to stop the current request, the client will receive the relevant parameters generated here.

Test

Run Unit Test Suites

cd /path/to/apisix-java-plugin-runner
 ./mvnw test

Mimic practical environment

If you want to mimic the practical environment, you need to configure the route on APISIX by having the request go through the filter you want to test, for example

"plugins":{
    "ext-plugin-pre-req":{
        "conf":[
            {
                "name":"FooFilter",
                "value":"bar"
            }
        ]
    }
}

and then make a request to APISIX to trigger the route.