code: // Licensed to the Software Freedom Conservancy (SFC) under one
  // or more contributor license agreements.  See the NOTICE file
  // distributed with this work for additional information
  // regarding copyright ownership.  The SFC licenses this file
  // to you under the Apache License, Version 2.0 (the
  // "License"); you may not use this file except in compliance
  // with the License.  You may obtain a copy of the License at
  //
  //   http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing,
  // software distributed under the License is distributed on an
  // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  // KIND, either express or implied.  See the License for the
  // specific language governing permissions and limitations
  // under the License.
  
  package org.openqa.selenium.docker.v1_41;
  
  import static org.openqa.selenium.docker.v1_41.V141Docker.DOCKER_API_VERSION;
  import static org.openqa.selenium.json.Json.JSON_UTF_8;
  import static org.openqa.selenium.json.Json.MAP_TYPE;
  import static org.openqa.selenium.remote.http.HttpMethod.POST;
  
  import java.util.Map;
  import java.util.logging.Logger;
  import org.openqa.selenium.docker.DockerException;
  import org.openqa.selenium.docker.internal.Reference;
  import org.openqa.selenium.internal.Require;
  import org.openqa.selenium.json.Json;
  import org.openqa.selenium.remote.http.Contents;
  import org.openqa.selenium.remote.http.HttpHandler;
  import org.openqa.selenium.remote.http.HttpRequest;
  import org.openqa.selenium.remote.http.HttpResponse;
  
  class PullImage {
    private static final Json JSON = new Json();
    private static final Logger LOG = Logger.getLogger(PullImage.class.getName());
    private final HttpHandler client;
  
    public PullImage(HttpHandler client) {
      this.client = Require.nonNull("HTTP client", client);
    }
  
    public void apply(Reference ref) {
      Require.nonNull("Reference to pull", ref);
  
      LOG.info("Pulling " + ref);
  
      String image = String.format("%s/%s", ref.getDomain(), ref.getName());
      HttpRequest req =
          new HttpRequest(POST, String.format("/v%s/images/create", DOCKER_API_VERSION))
              .addHeader("Content-Type", JSON_UTF_8)
              .addQueryParameter("fromImage", image);
  
      if (ref.getDigest() != null) {
        req.addQueryParameter("tag", ref.getDigest());
      } else if (ref.getTag() != null) {
        req.addQueryParameter("tag", ref.getTag());
      }
  
      HttpResponse res = client.execute(req);
  
      LOG.info("Have response from server");
  
      if (!res.isSuccessful()) {
        String message = "Unable to pull image: " + ref.getFamiliarName();
  
        try {
          Map<String, Object> value = JSON.toType(Contents.string(res), MAP_TYPE);
          message = (String) value.get("message");
        } catch (Exception e) {
          // fall through
        }
  
        throw new DockerException(message);
      }
    }
  }
  