我正在使用 Google Cloud 的 Java 数据存储客户端库来访问云数据存储。
备注 :我没有使用 App Engine 来部署我的应用程序;只是出于开发目的运行本地应用程序。
按照示例,我可以读取/写入 Cloud Datastore。
Datastore datastore = DatastoreOptions.defaultInstance().service();
KeyFactory keyFactory = datastore.newKeyFactory().setKind("MyKind");
Key key = keyFactory.newKey();
Entity entity = datastore.get(key);
我希望能够写入本地数据存储模拟器实例。
跟随指南 here , 我跑
gcloud beta emulators datastore start
.这显示在我的终端中:
C:\Users\User>gcloud beta emulators datastore start
WARNING: Reusing existing data in [C:\Users\User\AppData\Roaming\gcloud\emulators\datastore].
Executing: cmd /c C:\Users\User\AppData\Local\Google\Cloud SDK\google-cloud-sdk\platform\cloud-datastore-emulator\cloud_datastore_emulator.cmd start --host=localhost --port=8964 --store_on_disk=True --consistency=0.9 --allow_remote_shutdown C:\Users\User\AppData\Roaming\gcloud\emulators\datastore
[datastore] Oct 31, 2016 11:37:27 AM com.google.cloud.datastore.emulator.CloudDatastore$FakeDatastoreAction$7 apply
[datastore] INFO: Provided --allow_remote_shutdown to start command which is no longer necessary.
[datastore] Oct 31, 2016 11:37:27 AM com.google.cloud.datastore.emulator.impl.LocalDatastoreFileStub <init>
[datastore] INFO: Local Datastore initialized:
[datastore] Type: High Replication
[datastore] Storage: C:\Users\User\AppData\Roaming\gcloud\emulators\datastore\WEB-INF\appengine-generated\local_db.bin
[datastore] Oct 31, 2016 11:37:28 AM io.grpc.internal.ManagedChannelImpl <init>
[datastore] INFO: [ManagedChannelImpl@5e955596] Created with target localhost:8964
[datastore] Oct 31, 2016 11:37:28 AM com.google.cloud.datastore.emulator.impl.LocalDatastoreFileStub load
[datastore] INFO: The backing store, C:\Users\User\AppData\Roaming\gcloud\emulators\datastore\WEB-INF\appengine-generated\local_db.bin, does not exist. It will be created.
[datastore] Oct 31, 2016 11:37:28 AM io.gapi.emulators.netty.NettyUtil applyJava7LongHostnameWorkaround
[datastore] INFO: Unable to apply Java 7 long hostname workaround.
[datastore] API endpoint: http://localhost:8964
[datastore] If you are using a library that supports the DATASTORE_EMULATOR_HOST environment variable, run:
[datastore]
[datastore] export DATASTORE_EMULATOR_HOST=localhost:8964
[datastore]
[datastore] Dev App Server is now running.
[datastore]
我打开另一个终端并设置环境变量:
C:\Users\User>gcloud beta emulators datastore env-init > set_vars.cmd && set_vars.cmd
C:\Users\User>set DATASTORE_DATASET=my-project-id
C:\Users\User>set DATASTORE_EMULATOR_HOST=localhost:8964
C:\Users\User>set DATASTORE_EMULATOR_HOST_PATH=localhost:8964/datastore
C:\Users\User>set DATASTORE_HOST=http://localhost:8964
C:\Users\User>set DATASTORE_PROJECT_ID=my-project-id
我运行我的应用程序并进行 REST 调用以发布或检索实体,但这仅读取/写入云数据存储。前往
localhost:8964/datastore
给我 Not Found
.虽然启动模拟器告诉我它创建了 local_db.bin
文件,据说包含它的文件夹是空的。我还想避免使用 LocalDatastoreHelper 来访问本地模拟器。有什么办法可以只使用 gcloud 来实现吗?
最佳答案
我假设您想针对 Datastore Emulator 进行测试。在这种情况下,无需从 shell 启动数据存储模拟器。有一个LocalDatastoreHelper在 gcloud 库中,可让您轻松创建、启动、重置和停止本地数据存储模拟器。
我没有找到任何关于它的文档,所以我为你创建了这个测试用例:
import com.google.cloud.datastore.Datastore;
import com.google.cloud.datastore.DatastoreOptions;
import com.google.cloud.datastore.Entity;
import com.google.cloud.datastore.KeyFactory;
import com.google.cloud.datastore.testing.LocalDatastoreHelper;
import org.junit.*;
import java.io.IOException;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertNull;
/**
* This testcase demonstrate the use of the datastore emulator in JUnit test cases.
*
* from @link https://www.kontaktlinsen-preisvergleich.de
*/
public class DatastoreEmulatorTest {
protected static LocalDatastoreHelper localDatastoreHelper;
protected Datastore datastore;
protected KeyFactory keyFactory;
@BeforeClass
public static void setUpClass() throws InterruptedException, IOException {
// create and start a local datastore emulator on a random free port
// this also means that you probably can run tests like this concurrently.
System.out.println("[Datastore-Emulator] start");
localDatastoreHelper = LocalDatastoreHelper.create();
localDatastoreHelper.start();
System.out.println("[Datastore-Emulator] listening on port: " + localDatastoreHelper.getPort());
// set the system property to tell the gcloud lib to use the datastore emulator
System.setProperty("DATASTORE_EMULATOR_HOST","localhost:" + localDatastoreHelper.getPort());
}
@Before
public void setUp() {
// create the datastore instance
// because of the system property set it in setUpClass() this
// datastore will be connected with the datastore emulator.
datastore = DatastoreOptions.getDefaultInstance().getService();
keyFactory = datastore.newKeyFactory().setKind("TestEntity");
}
@After
public void tearDown() throws IOException {
System.out.println("[Datastore-Emulator] reset");
// this resets the datastore after every test
localDatastoreHelper.reset();
}
@AfterClass
public static void tearDownClass() throws InterruptedException, IOException {
System.out.println("[Datastore-Emulator] stop");
// this stops the datastore emulator after all tests are done
localDatastoreHelper.stop();
}
@Test
public void test1() {
// stores an entity in the datastore and retrieves it later
// create an Entity "TestEntity"
Entity.Builder builder = Entity.newBuilder(keyFactory.newKey(42));
builder.set("name", "Test1");
// store it in datastore
datastore.put(builder.build());
// retrieve entity by key
Entity entity = datastore.get(keyFactory.newKey(42));
assertNotNull(entity);
assertEquals("Test1", entity.getString("name"));
}
@Test
public void test2() {
// try to access the entity created in test1, shouldn't work because
// of calling reset in tearDown() after each test.
// try to retrieve entity by key
Entity entity = datastore.get(keyFactory.newKey(42));
assertNull(entity);
}
}
LocalDatastoreHelper 在空闲端口上创建一个 Datastore Emulator 实例并且不存储到磁盘 - 当您使用调试器停止测试用例并查找进程时,您会发现如下内容:
$ ps ax | grep CloudDatastore
2614 ?? R 0:01.39 /usr/bin/java -cp /Users/marco/google-cloud-sdk/platform/cloud-datastore-emulator/CloudDatastore.jar com.google.cloud.datastore.emulator.CloudDatastore /Users/marco/google-cloud-sdk/platform/cloud-datastore-emulator/cloud_datastore_emulator start --host=localhost --port=57640 --store_on_disk=False --consistency=0.9 --allow_remote_shutdown /var/folders/ky/c126qk_161159ltyrbpdxv8w0000gn/T/gcd2141205756617995044
这也意味着您也应该能够并行运行测试。
关于java - 使用 Java 的 Google 数据存储模拟器(不使用 GAE),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/40348653/