content: package com.ctrip.framework.apollo.portal.component;
  
  import com.google.common.collect.Lists;
  
  import com.ctrip.framework.apollo.core.MetaDomainConsts;
  import com.ctrip.framework.apollo.core.dto.ServiceDTO;
  import com.ctrip.framework.apollo.core.enums.Env;
  import com.ctrip.framework.apollo.core.utils.ApolloThreadFactory;
  import com.ctrip.framework.apollo.tracer.Tracer;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.boot.autoconfigure.web.HttpMessageConverters;
  import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
  import org.springframework.http.client.SimpleClientHttpRequestFactory;
  import org.springframework.stereotype.Component;
  import org.springframework.util.CollectionUtils;
  import org.springframework.web.client.RestTemplate;
  
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.Executors;
  import java.util.concurrent.ScheduledExecutorService;
  import java.util.concurrent.TimeUnit;
  
  import javax.annotation.PostConstruct;
  
  @Component
  public class AdminServiceAddressLocator {
  
    private static final long NORMAL_REFRESH_INTERVAL = 5 * 60 * 1000;
    private static final long OFFLINE_REFRESH_INTERVAL = 10 * 1000;
    private static final int RETRY_TIMES = 3;
    private static final String ADMIN_SERVICE_URL_PATH = "/services/admin";
    private static final Logger logger = LoggerFactory.getLogger(AdminServiceAddressLocator.class);
  
    private ScheduledExecutorService refreshServiceAddressService;
    private RestTemplate restTemplate;
    private List<Env> allEnvs;
    private Map<Env, List<ServiceDTO>> cache = new ConcurrentHashMap<>();
  
    @Autowired
    private HttpMessageConverters httpMessageConverters;
    @Autowired
    private PortalSettings portalSettings;
    @Autowired
    private RestTemplateFactory restTemplateFactory;
  
    @PostConstruct
    public void init() {
      allEnvs = portalSettings.getAllEnvs();
  
      //init restTemplate
      restTemplate = restTemplateFactory.getObject();
  
      refreshServiceAddressService =
          Executors.newScheduledThreadPool(1, ApolloThreadFactory.create("ServiceLocator", true));
  
      refreshServiceAddressService.schedule(new RefreshAdminServerAddressTask(), 1, TimeUnit.MILLISECONDS);
    }
  
    public List<ServiceDTO> getServiceList(Env env) {
      List<ServiceDTO> services = cache.get(env);
      if (CollectionUtils.isEmpty(services)) {
        return Collections.emptyList();
      }
      List<ServiceDTO> randomConfigServices = Lists.newArrayList(services);
      Collections.shuffle(randomConfigServices);
      return randomConfigServices;
    }
  
    //maintain admin server address
    private class RefreshAdminServerAddressTask implements Runnable {
  
      @Override
      public void run() {
        boolean refreshSuccess = true;
        //refresh fail if get any env address fail
        for (Env env : allEnvs) {
          boolean currentEnvRefreshResult = refreshServerAddressCache(env);
          refreshSuccess = refreshSuccess && currentEnvRefreshResult;
        }
  
        if (refreshSuccess) {
          refreshServiceAddressService
              .schedule(new RefreshAdminServerAddressTask(), NORMAL_REFRESH_INTERVAL, TimeUnit.MILLISECONDS);
        } else {
          refreshServiceAddressService
              .schedule(new RefreshAdminServerAddressTask(), OFFLINE_REFRESH_INTERVAL, TimeUnit.MILLISECONDS);
        }
      }
    }
  
    private boolean refreshServerAddressCache(Env env) {
  
      for (int i = 0; i < RETRY_TIMES; i++) {
  
        try {
          ServiceDTO[] services = getAdminServerAddress(env);
          if (services == null || services.length == 0) {
            continue;
          }
          cache.put(env, Arrays.asList(services));
          return true;
        } catch (Throwable e) {
          logger.error(String.format("Get admin server address from meta server failed. env: %s, meta server address:%s",
                                     env, MetaDomainConsts.getDomain(env)), e);
          Tracer
              .logError(String.format("Get admin server address from meta server failed. env: %s, meta server address:%s",
                                      env, MetaDomainConsts.getDomain(env)), e);
        }
      }
      return false;
    }
  
    private ServiceDTO[] getAdminServerAddress(Env env) {
      String domainName = MetaDomainConsts.getDomain(env);
      String url = domainName + ADMIN_SERVICE_URL_PATH;
      return restTemplate.getForObject(url, ServiceDTO[].class);
    }
  
  
  }
  