微服务

Ribbon是微服务的一个核心基础组件，提供多协议HTTP、TCP以及UDP的服务调用RPC功能以及负载均衡功能。

Ribbon：一个客户端IPC（Inter Process Communication）库，RPC(Remote Procedure Calls)库。支持负载均衡、故障容错、多协议支持：HTTP, TCP, UDP，支持异步（asynchronous）以及reactive模型、Caching 以及batching。

 

Ribbon 注解方式

 

举例某个api应用，运行了两个实例（部署了2台机器），这个应用提供了两个api：

1、/test

2、/test/{version}

这两个api都有个参数data，/test/{version}还有个@PathVariable的version参数。

/test定义如下：

@ResponseBody
@RequestMapping(value = "test")
public String test(@RequestParam String data) {
    return data;
}

/test/{version}定义如下：

@ResponseBody
@RequestMapping(value = "test/{version}")
public String testvn(@PathVariable String version, @RequestParam String data) {
    return data + ";version=" + version;
}

就是两个普通的api，和我们以前写的api是一样的，可以直接请求：

http://localhost:8081/test?data=aaa

http://localhost:8082/test?data=aaa

 

http://localhost:8081/test/1.0?data=aaa

http://localhost:8082/test/1.0?data=aaa

 

通过ribbon调用这俩个api服务：

 

注解方式：

public interface TestService {

    @Http(
            method = Http.HttpMethod.GET,
            uri = "/test?data={data}"
    )
    RibbonRequest<ByteBuf> test(@Var("data") String data);

    @Http(
            method = Http.HttpMethod.GET,
            uri = "/test/{version}?data={data}"
    )
    RibbonRequest<ByteBuf> testvn(@Var("version") String version, @Var("data") String data);
}

通过ribbon调用/test服务：

@Test
public void test11() {
    ConfigurationManager.getConfigInstance().setProperty("TestService.ribbon." + CommonClientConfigKey.MaxAutoRetriesNextServer, "3");
    ConfigurationManager.getConfigInstance().setProperty("TestService.ribbon." + CommonClientConfigKey.ListOfServers, "localhost:8082,localhost:8081");

    TestService testService = Ribbon.from(TestService.class);
    RibbonRequest<ByteBuf> request = testService.test("aaa");

    ByteBuf result0 = request.execute();
    ByteBuffer buf = result0.nioBuffer();
    byte[] bytes = new byte[buf.remaining()];
    buf.get(bytes);
    System.out.println(new String(bytes));
}

通过ribbon调用/test/{version}服务：

@Test
public void test21() {
    ConfigurationManager.getConfigInstance().setProperty("TestService.ribbon." + CommonClientConfigKey.MaxAutoRetriesNextServer, "3");
    ConfigurationManager.getConfigInstance().setProperty("TestService.ribbon." + CommonClientConfigKey.ListOfServers, "localhost:8082,localhost:8081");

    TestService testService = Ribbon.from(TestService.class);
    RibbonRequest<ByteBuf> request = testService.testvn("1.0", "aaa");

    ByteBuf result0 = request.execute();
    ByteBuffer buf = result0.nioBuffer();
    byte[] bytes = new byte[buf.remaining()];
    buf.get(bytes);
    System.out.println(new String(bytes));
}

 

 

 

Case: Instant messaging communication  over XMPP base TCP

 

----------------------------------------------------------------

 

Little thinking of interpreting XML document using automata

 

Little thinking of interpreting XML document using automata

 

- Attachment are just to attempt to interpret a simple document element like:

 

<e from='[e-mail]' to='localhost.com' version='1.0' xml:lang='en' xmlns='jx:clc' xmlns:e='http://ex.jx.org/e'>

 

the element is not a completed XML document element util.

 

 

-----------------------------------------------------------------------

Ribbon：一个客户端IPC（Inter Process Communication）库，RPC(Remote Procedure Calls)库。支持负载均衡、故障容错、多协议支持：HTTP, TCP, UDP，支持异步（asynchronous）以及reactive模型、Caching 以及batching。

 

Ribbon和Eureka配合用于发现查找注册的服务。Ribbon根据查找到的服务列表负责将请求路由转发到后端的服务（负载均衡）。

 

Eureka是一个微服务注册中心（registry），服务通过将自己注册在registry以便于服务进行发现定位查找。

 

HTTP请求，Template方式：
http://localhost:8081/test?data=aaa

@Test
public void test1() {
    HttpResourceGroup httpResourceGroup = Ribbon.createHttpResourceGroup("movieServiceClient",
            ClientOptions.create()
                    .withMaxAutoRetriesNextServer(3)
                    .withConfigurationBasedServerList("localhost:8082,localhost:8081"));
    HttpRequestTemplate<ByteBuf> recommendationsByUserIdTemplate = httpResourceGroup.newTemplateBuilder("recommendationsByUserId", ByteBuf.class)
            .withMethod("GET")
            .withUriTemplate("/test?data=aaa")
//                .withFallbackProvider(new RecommendationServiceFallbackHandler())
//                .withResponseValidator(new RecommendationServiceResponseValidator())
            .build();
    RibbonRequest<ByteBuf> request = recommendationsByUserIdTemplate.requestBuilder()
            .build();


    // Observable<ByteBuf> result = request.observe();


    ByteBuf result0 = request.execute();
    ByteBuffer buf = result0.nioBuffer();
    byte[] bytes = new byte[buf.remaining()];
    buf.get(bytes);
    System.out.println(new String(bytes));
}

 http://localhost:8082/test/1.0?data=aaa

@Test
public void test2() {
    HttpResourceGroup httpResourceGroup = Ribbon.createHttpResourceGroup("movieServiceClient",
            ClientOptions.create()
                    .withMaxAutoRetriesNextServer(3)
                    .withConfigurationBasedServerList("localhost:8082,localhost:8081"));
    HttpRequestTemplate<ByteBuf> recommendationsByUserIdTemplate = httpResourceGroup.newTemplateBuilder("recommendationsByUserId", ByteBuf.class)
            .withMethod("GET")
            .withUriTemplate("/test/{version}?data=aaa")
//                .withFallbackProvider(new RecommendationServiceFallbackHandler())
//                .withResponseValidator(new RecommendationServiceResponseValidator())
            .build();
    RibbonRequest<ByteBuf> request = recommendationsByUserIdTemplate.requestBuilder()
            .withRequestProperty("version", "1.0")
            .build();


    // Observable<ByteBuf> result = request.observe();


    ByteBuf result0 = request.execute();
    ByteBuffer buf = result0.nioBuffer();
    byte[] bytes = new byte[buf.remaining()];
    buf.get(bytes);
    System.out.println(new String(bytes));
}

 注解方式：

public interface TestService {

    @Http(
            method = Http.HttpMethod.GET,
            uri = "/test?data={data}"
    )
    RibbonRequest<ByteBuf> test(@Var("data") String data);

    @Http(
            method = Http.HttpMethod.GET,
            uri = "/test/{version}?data={data}"
    )
    RibbonRequest<ByteBuf> testvn(@Var("version") String version, @Var("data") String data);
}

 

@Test
public void test11() {
    ConfigurationManager.getConfigInstance().setProperty("TestService.ribbon." + CommonClientConfigKey.MaxAutoRetriesNextServer, "3");
    ConfigurationManager.getConfigInstance().setProperty("TestService.ribbon." + CommonClientConfigKey.ListOfServers, "localhost:8082,localhost:8081");

    TestService testService = Ribbon.from(TestService.class);
    RibbonRequest<ByteBuf> request = testService.test("aaa");

    ByteBuf result0 = request.execute();
    ByteBuffer buf = result0.nioBuffer();
    byte[] bytes = new byte[buf.remaining()];
    buf.get(bytes);
    System.out.println(new String(bytes));
}

 

@Test
public void test21() {
    ConfigurationManager.getConfigInstance().setProperty("TestService.ribbon." + CommonClientConfigKey.MaxAutoRetriesNextServer, "3");
    ConfigurationManager.getConfigInstance().setProperty("TestService.ribbon." + CommonClientConfigKey.ListOfServers, "localhost:8082,localhost:8081");

    TestService testService = Ribbon.from(TestService.class);
    RibbonRequest<ByteBuf> request = testService.testvn("1.0", "aaa");

    ByteBuf result0 = request.execute();
    ByteBuffer buf = result0.nioBuffer();
    byte[] bytes = new byte[buf.remaining()];
    buf.get(bytes);
    System.out.println(new String(bytes));
}

负载均衡

class URLConnectionLoadBalancer {

    private final ILoadBalancer loadBalancer;
    // retry handler that does not retry on same server, but on a different server
    private final RetryHandler retryHandler = new DefaultLoadBalancerRetryHandler(0, 1, true);

    public URLConnectionLoadBalancer(List<Server> serverList) {
        loadBalancer = LoadBalancerBuilder.newBuilder().buildFixedServerListLoadBalancer(serverList);
    }

    public String call(final String path) throws Exception {
        return LoadBalancerCommand.<String>builder()
                .withLoadBalancer(loadBalancer)
                .build()
                .submit(new ServerOperation<String>() {
                    @Override
                    public Observable<String> call(Server server) {
                        URL url;
                        try {
                            url = new URL("http://" + server.getHost() + ":" + server.getPort() + path);
                            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                            
                            InputStream is = conn.getInputStream();
                            ByteArrayOutputStream os = new ByteArrayOutputStream();
                            byte[] bytes = new byte[1024];
                            int nbytes = -1;
                            while ((nbytes = is.read(bytes)) > 0) {
                                os.write(bytes, 0, nbytes);
                            }
                            String content = new String(bytes);
                            content = content.trim();
                            
//                            content = conn.getResponseMessage();
                            
                            return Observable.just(content);
                        } catch (Exception e) {
                            return Observable.error(e);
                        }
                    }
                }).toBlocking().first();
    }

    public LoadBalancerStats getLoadBalancerStats() {
        return ((BaseLoadBalancer) loadBalancer).getLoadBalancerStats();
    }
}

 

@Test
public void test() {
    URLConnectionLoadBalancer urlLoadBalancer = new URLConnectionLoadBalancer(Lists.newArrayList(
            new Server("localhost", 8081),
            new Server("localhost", 8082)));
    for (int i = 0; i < 6; i++) {
        try {
            System.out.println(urlLoadBalancer.call("/test?data=aaa"));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    System.out.println("=== Load balancer stats ===");
    System.out.println(urlLoadBalancer.getLoadBalancerStats());
}

 

1、https://github.com/Netflix/eureka

 

 

Ribbon还提供了一个template方式来请求HTTP资源，Template方式可参考文章: https://lobin.iteye.com/blog/1576159。

Ribbon负载均衡例子参考文章: https://lobin.iteye.com/blog/1576159。

 

 

 

1、https://github.com/Netflix/ribbon