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(new SentinelOkHttpConfig()))
        .build();

Configuration

SentinelOkHttpConfig configuration:

|name|description|type|default value||------|------------|------|-------||resourcePrefix|customized resource name prefix|String|okhttp:||resourceExtractor|customized resource extractor|OkHttpResourceExtractor|DefaultOkHttpResourceExtractor||fallback|handle request when it is blocked|OkHttpFallback|DefaultOkHttpFallback|

Resource Extractor

We can define OkHttpResourceExtractor to customize the logic of extracting resource name from the HTTP request. 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;
};

The pattern of default resource name extractor is ${HTTP_METHOD}:${URL} (e.g. GET:/foo).

Fallback (Block handling)

We can define OkHttpFallback to handle blocked request. For example:

public class DefaultOkHttpFallback implements OkHttpFallback {

    @Override
    public Response handle(Request request, Connection connection, BlockException e) {
        return new Response(myErrorBuilder);
    }
}