content: package com.alipay.api.kms.aliyun.credentials.provider;
  
  import com.alibaba.fastjson.JSON;
  import com.alibaba.fastjson.JSONObject;
  import com.alipay.api.kms.aliyun.credentials.EcsRamRoleCredentials;
  import com.alipay.api.kms.aliyun.credentials.exceptions.CredentialsException;
  import com.alipay.api.kms.aliyun.http.CompatibleUrlConnClient;
  import com.alipay.api.kms.aliyun.http.HttpRequest;
  import com.alipay.api.kms.aliyun.http.HttpResponse;
  import com.alipay.api.kms.aliyun.http.MethodType;
  
  import java.net.HttpURLConnection;
  import java.net.MalformedURLException;
  import java.net.URL;
  
  public class ECSMetadataServiceCredentialFetcher {
      private static final String URL_IN_ECS_METADATA = "/latest/meta-data/ram/security-credentials/";
      private static final int DEFAULT_TIMEOUT_IN_MILLISECONDS = 5000;
      private static final String ECS_METADAT_FETCH_ERROR_MSG = "Failed to get RAM session credentials from ECS metadata service.";
      private static final int DEFAULT_ECS_SESSION_TOKEN_DURATION_SECONDS = 3600 * 6;
      private URL credentialUrl;
      private String roleName;
      private String metadataServiceHost = "100.100.100.200";
      private int connectionTimeoutInMilliseconds;
  
      public ECSMetadataServiceCredentialFetcher() {
          this.connectionTimeoutInMilliseconds = DEFAULT_TIMEOUT_IN_MILLISECONDS;
      }
  
      public void setRoleName(String roleName) {
          if (null == roleName) {
              throw new NullPointerException("You must specifiy a valid role name.");
          }
          this.roleName = roleName;
          setCredentialUrl();
      }
  
      private void setCredentialUrl() {
          try {
              this.credentialUrl = new URL("http://" + metadataServiceHost + URL_IN_ECS_METADATA + roleName);
          } catch (MalformedURLException e) {
              throw new IllegalArgumentException(e.toString());
          }
      }
  
      public ECSMetadataServiceCredentialFetcher withECSMetadataServiceHost(String host) {
          System.err.println("withECSMetadataServiceHost() method is only for testing, please don't use it");
          this.metadataServiceHost = host;
          setCredentialUrl();
          return this;
      }
  
      public ECSMetadataServiceCredentialFetcher withConnectionTimeout(int milliseconds) {
          this.connectionTimeoutInMilliseconds = milliseconds;
          return this;
      }
  
      public String getMetadata() throws CredentialsException {
          HttpRequest request = new HttpRequest(credentialUrl.toString());
          request.setMethod(MethodType.GET);
          request.setConnectTimeout(connectionTimeoutInMilliseconds);
          request.setReadTimeout(connectionTimeoutInMilliseconds);
          HttpResponse response;
  
          try {
              response = CompatibleUrlConnClient.compatibleGetResponse(request);
          } catch (Exception e) {
              throw new CredentialsException("Failed to connect ECS Metadata Service: " + e.toString());
          }
  
          if (response.getStatus() != HttpURLConnection.HTTP_OK) {
              throw new CredentialsException(ECS_METADAT_FETCH_ERROR_MSG + " HttpCode=" + response.getStatus());
          }
  
          return new String(response.getHttpContent());
      }
  
      public EcsRamRoleCredentials fetch() throws CredentialsException {
          String jsonContent = getMetadata();
          JSONObject jsonObject;
          jsonObject = JSON.parseObject(jsonContent);
  
          if (jsonObject.containsKey("Code") && jsonObject.containsKey("AccessKeyId") && jsonObject.containsKey("AccessKeySecret") && jsonObject
                  .containsKey("SecurityToken") && jsonObject.containsKey("Expiration")) {
          } else {
              throw new CredentialsException("Invalid json got from ECS Metadata service.");
          }
  
          if (!"Success".equals(jsonObject.getString("Code"))) {
              throw new CredentialsException(ECS_METADAT_FETCH_ERROR_MSG);
          }
          return new EcsRamRoleCredentials(jsonObject.getString("AccessKeyId"), jsonObject.getString(
                  "AccessKeySecret"), jsonObject.getString("SecurityToken"), jsonObject.getString(
                  "Expiration"), DEFAULT_ECS_SESSION_TOKEN_DURATION_SECONDS);
      }
  
      public EcsRamRoleCredentials fetch(int retryTimes) throws CredentialsException {
          for (int i = 0; i <= retryTimes; i++) {
              try {
                  return fetch();
              } catch (CredentialsException e) {
                  if (i == retryTimes) {
                      throw e;
                  }
              }
          }
          throw new CredentialsException("Failed to connect ECS Metadata Service: Max retry times exceeded.");
      }
  }
  