Sentinel/sentinel-adapter/sentinel-okhttp-adapter/README.md

Sentinel OkHttp Adapter

Introduction

Sentinel provides integration for OkHttp client to enable flow control for web requests.

Add the following dependency in pom.xml (if you are using Maven):

<dependency>
    <groupId>com.alibaba.csp</groupId>
    <artifactId>sentinel-okhttp-adapter</artifactId>
    <version>x.y.z</version>
</dependency>

We can add the SentinelOkHttpInterceptor interceptor when OkHttpClient at initialization, for example:

OkHttpClient client = new OkHttpClient.Builder()
        .addInterceptor(new SentinelOkHttpInterceptor())
        .build();

Configuration

• SentinelOkHttpConfig configuration:

name	description	type	default value
extractor	custom resource extractor	OkHttpResourceExtractor	DefaultOkHttpResourceExtractor
fallback	handle request when it is blocked	OkHttpFallback	DefaultOkHttpFallback

extractor (resource extractor)

We can define OkHttpResourceExtractor to custom resource extractor replace DefaultOkHttpResourceExtractor, for example: okhttp:GET:ip:port/okhttp/back/1 ==> /okhttp/back/{id}

OkHttpResourceExtractor extractor = (request, connection) -> {
    String resource = request.url().toString();
    String regex = "/okhttp/back/";
    if (resource.contains(regex)) {
        resource = resource.substring(0, resource.indexOf(regex) + regex.length()) + "{id}";
    }
    return resource;
};
SentinelOkHttpConfig.setExtractor(extractor);

fallback (Block handling)

We can define OkHttpFallback to handle request is blocked according to the actual scenario, for example:

public class DefaultOkHttpFallback implements OkHttpFallback {

    @Override
    public Response handle(Request request, Connection connection, BlockException e) {
        // Just wrap and throw the exception.
        throw new SentinelRpcException(e);
    }
}