Вы можете создать каркас для App Egnine с помощью , следуя этим инструкциям .
Получив скелет, добавьте что-то подобное для обработки запросов на экспорт:
CloudDatastoreExport.java
package com.google.example.datastore;
import com.google.appengine.api.appidentity.AppIdentityService;
import com.google.appengine.api.appidentity.AppIdentityServiceFactory;
import com.google.apphosting.api.ApiProxy;
import com.google.common.io.CharStreams;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.logging.Logger;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.json.JSONArray;
import org.json.JSONObject;
import org.json.JSONTokener;
@WebServlet(name = "CloudDatastoreExport", value = "/cloud-datastore-export")
public class CloudDatastoreExport extends HttpServlet {
private static final Logger log = Logger.getLogger(CloudDatastoreExport.class.getName());
@Override
public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
// Verify outputURL parameter
String outputUrlPrefix = request.getParameter("output_url_prefix");
if (outputUrlPrefix == null || !outputUrlPrefix.matches("^gs://.*")) {
response.setStatus(HttpServletResponse.SC_CONFLICT);
response.setContentType("text/plain");
response.getWriter().println("Error: Must provide a valid output_url_prefix.");
} else {
// Get project ID
String projectId = ApiProxy.getCurrentEnvironment().getAppId();
// Remove partition information to get plain app ID
String appId = projectId.replaceFirst("(.*~)", "");
// Get access token
ArrayList<String> scopes = new ArrayList<String>();
scopes.add("https://www.googleapis.com/auth/datastore");
final AppIdentityService appIdentity = AppIdentityServiceFactory.getAppIdentityService();
final AppIdentityService.GetAccessTokenResult accessToken =
appIdentity.getAccessToken(scopes);
// Read export parameters
// If output prefix does not end with slash, add a timestamp
if (!outputUrlPrefix.substring(outputUrlPrefix.length() - 1).contentEquals("/")) {
String timeStamp = new SimpleDateFormat("yyyyMMddHHmmss").format(new Date());
outputUrlPrefix = outputUrlPrefix + "/" + timeStamp + "/";
}
String[] namespaces = request.getParameterValues("namespace_id");
String[] kinds = request.getParameterValues("kind");
// Build export request
JSONObject exportRequest = new JSONObject();
exportRequest.put("output_url_prefix", outputUrlPrefix);
JSONObject entityFilter = new JSONObject();
if (kinds != null) {
JSONArray kindsJSON = new JSONArray(kinds);
entityFilter.put("kinds", kinds);
}
if (namespaces != null) {
JSONArray namespacesJSON = new JSONArray(namespaces);
entityFilter.put("namespaceIds", namespacesJSON);
}
exportRequest.put("entityFilter", entityFilter);
URL url = new URL("https://datastore.googleapis.com/v1/projects/" + appId + ":export");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setRequestMethod("POST");
connection.addRequestProperty("Content-Type", "application/json");
connection.addRequestProperty("Authorization", "Bearer " + accessToken.getAccessToken());
OutputStreamWriter writer = new OutputStreamWriter(connection.getOutputStream());
exportRequest.write(writer);
writer.close();
if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
JSONTokener exportResponseTokens = new JSONTokener(connection.getInputStream());
JSONObject exportResponse = new JSONObject(exportResponseTokens);
response.setContentType("text/plain");
response.getWriter().println("Export started:\n" + exportResponse.toString(4));
} else {
InputStream s = connection.getErrorStream();
InputStreamReader r = new InputStreamReader(s, StandardCharsets.UTF_8);
String errorMessage =
String.format(
"got error (%d) response %s from %s",
connection.getResponseCode(), CharStreams.toString(r), connection.toString());
log.warning(errorMessage);
response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
response.setContentType("text/plain");
response.getWriter().println("Failed to initiate export.");
}
}
}
}
Вы можете использовать тот же cron.yaml из документов:
cron:
- description: "Daily Cloud Datastore Export"
url: /cloud-datastore-export?namespace_id=&output_url_prefix=gs://BUCKET_NAME[/NAMESPACE_PATH]
target: cloud-datastore-admin
schedule: every 24 hours
Используйте gcloud для развертывания задания cron:
gcloud app deploy cron.yaml
Убедитесь, что вы выполнили эту часть, чтобы дать разрешения на экспорт и ведение GAE, иначе вы получите ошибки об отказе в разрешении:
https://cloud.google.com/datastore/docs/schedule-export#before_you_begin