http_client.java

package com.example.http;

import com.squareup.okhttp.Interceptor;
import com.squareup.okhttp.OkHttpClient;
import com.squareup.okhttp.Request;
import com.squareup.okhttp.Response;

import java.io.IOException;

import io.opentelemetry.api.trace.SpanKind;
import io.opentelemetry.extension.annotations.WithSpan;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Application {

    private static final Logger LOGGER = LoggerFactory.getLogger(Application.class);
    private static final String URL = "http://localhost:8080/send?message=hi there";

    public static void main(String ... args) throws IOException {
        AppTries(new OkHttpClient());

        InterceptorTries(new OkHttpClient());
    }

    @WithSpan
    public static void InterceptorTries(OkHttpClient client) {
        client.interceptors().add(new Interceptor() {
            @Override
            public Response intercept(Interceptor.Chain chain) throws IOException {
                Request request = chain.request();
                Response response = chain.proceed(request);
                int tryCount = 0;
                while (!response.isSuccessful() && tryCount < 3) {
                    tryCount++;
                    // we'd need backoff amd jitter
                    response = chain.proceed(request);
                }
                return response;
            }
        });

        String responseBody = null;
        try {
            responseBody = makeCall(client, URL);
        } catch (Exception ex) {
        }

        LOGGER.info("Received response={}", responseBody);
    }

    @WithSpan(kind = SpanKind.SERVER)
    public static void AppTries(OkHttpClient client) {
        String responseBody = null;
        for (int tryCount = 0; tryCount < 3; tryCount ++) {
            try {
                responseBody = makeCall(client, URL);
                if (responseBody != null) {
                    break;
                }
            } catch (Exception ex) {
            }
          
             // we'd need backoff amd jitter
        }

        LOGGER.info("Received response={}", responseBody);
    }

    private static String makeCall(OkHttpClient client, String url) throws IOException {
        Request request = new Request.Builder()
                .url(url)
                .build();
        Response response = client.newCall(request).execute();
        return response.isSuccessful() ? String.valueOf(response.body().string()) : null;
    }
}