使用Java的Google数据存储模拟器（不使用GAE） [英] Google Datastore Emulator using Java (Not using GAE)

问题描述

我使用Google Cloud的Datastore Client Library for Java来访问云数据存储。

注意：我没有使用App Engine部署我的应用程序;只需运行本地应用程序进行开发即可。

以下示例可以读取/写入Cloud Datastore。

  Datastore datastore = DatastoreOptions.defaultInstance（）。service（）; 
 KeyFactory keyFactory = datastore.newKeyFactory（）。setKind（MyKind）; 
 Key key = keyFactory.newKey（）; 
实体实体= datastore.get（key）; 
  

我希望能够写入本地数据存储模拟器实例。
按照这里的指导，我运行 gcloud beta模拟器数据存储开始。
这显示在我的终端：

  C：\Users\User> gcloud beta模拟器数据存储开始
警告：重新使用[C：\ Users \ User\AppData\Roaming\gcloud\emulators\datastore〕中的现有数据。 
执行：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]信息：提供--allow_remote_shutdown启动命令更长的必要。 
 [datastore] Oct 31，2016 11:37:27 AM com.google.cloud.datastore.emulator.impl.LocalDatastoreFileStub< init> 
 [datastore] INFO：本地数据存储已初始化：
 [数据存储]类型：高复制
 [数据存储]存储：C：\ Users \ Users \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]使用target localhost创建：8964 
 [datastore] 2016年10月31日上午11:37:28 com.google.cloud.datastore.emulator.impl.LocalDatastoreFileStub加载
 [数据存储] INFO：后备存储，C：\ Users \User\AppData\Roaming\gcloud\emulators\datastore\WEB-INF\appengine-generated\local_db .bin，不存在。它将被创建。 
 [datastore] Oct 31，2016 11:37:28 AM io.gapi.emulators.netty.NettyUtil applyJava7LongHostnameWorkaround 
 [datastore]信息：无法应用Java 7 long hostname解决方法。 
 [datastore] API端点：http：// localhost：8964 
 [datastore]如果您使用支持DATASTORE_EMULATOR_HOST环境变量的库，请运行：
 [datastore] 
 [数据存储]导出DATASTORE_EMULATOR_HOST =本地主机：8964 
 [数据存储] 
 [数据存储] Dev App Server现在正在运行。 
 [datastore] 
  

我打开另一个终端并设置环境变量：

  C：\Users\User> gcloud beta模拟器数据存储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 \\ Users \\ gt; set DATASTORE_EMULATOR_HOST_PATH = localhost：8964 / datastore 
 C：\Users\User> set DATASTORE_HOST = http：// localhost：8964 
 C：\ Users \ User>设置DATASTORE_PROJECT_ID = my-project-id 
  

我运行我的应用程序并进行REST调用以发布或检索一个实体，但这只能读取/写入云数据存储。标题为 localhost：8964 / datastore 给我未找到。尽管启动模拟器告诉我它已经创建了 local_db.bin 文件，据说包含它的文件夹是空的。
我也想远离使用LocalDatastoreHelper来访问本地模拟器。是否有任何方法可以实现使用gcloud？

解决方案

下面的代码总是连接到远程数据存储。使用gcloud设置的默认选项（例如项目，授权凭证）。

  Datastore datastore = DatastoreOptions.defaultInstance（）。service（）; 
  

要连接到本地数据存储，请尝试以下操作：


@Test
public void test1（）throws IOException，InterruptedException {
Datastore ds = DatastoreOptions.builder（）。host（http：/ /本地主机：9999 ）专案编号（ 我的项目）建设（）服务（）;
com.google.cloud.datastore.Key key = ds.newKeyFactory（）。kind（MyEntity）。newKey（mykey）;
com.google.cloud.datastore.Entity entity = com.google.cloud.datastore.Entity.builder（key）.set（p1，Hello World！）。build（）;
entity = ds.put（entity）;
entity = ds.get（key）;
System.out.println（entity）;
}


我在localhost：9999上启动了我的数据存储模拟器。在构建DatastoreOptions时将其设置为主机。

我已确认模拟器控制台显示接收到请求并且实体持续存在。我也检查过数据文件（local_db.bin），它显示数据（当然它不是纯文本文件）。

我不知道的一件事是 - 如果有办法通过浏览器界面来管理本地数据存储。我无法找到有关如何管理本地数据存储的文档，就像我们如何从云端控制台执行远程数据存储一样。也许别人可以帮助解决这个问题。

I am using Google Cloud's Datastore Client Library for Java to access the Cloud Datastore.

Note: I am not using App Engine to deploy my application; just running a local application for development purposes.

Following the example, I can read/write to the Cloud Datastore.

Datastore datastore = DatastoreOptions.defaultInstance().service();
KeyFactory keyFactory = datastore.newKeyFactory().setKind("MyKind");
Key key = keyFactory.newKey();
Entity entity = datastore.get(key);

I want to be able to write to a local Datastore emulator instance instead. Following the guide here, I run gcloud beta emulators datastore start. This shows up in my terminal:

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]

I open another terminal and set the environment variables:

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

I run my application and make a REST call to post or retrieve an Entity, but this only reads/writes against the Cloud Datastore. Heading to localhost:8964/datastore gives me Not Found. Although starting the emulator tells me that it created local_db.bin file, the folder supposedly containing it is empty. I also want to stay away from using LocalDatastoreHelper in order to access the local emulator. Is there any way to achieve using gcloud only ?

解决方案

The line below always connects to the remote datastore. Uses the default options (e.g. project, auth credentials) from gcloud settings.

Datastore datastore = DatastoreOptions.defaultInstance().service();

To connect to the local datastore, try the below:

@Test public void test1() throws IOException, InterruptedException { Datastore ds = DatastoreOptions.builder().host("http://localhost:9999").projectId("my-project").build().service(); com.google.cloud.datastore.Key key = ds.newKeyFactory().kind("MyEntity").newKey("mykey"); com.google.cloud.datastore.Entity entity = com.google.cloud.datastore.Entity.builder(key).set("p1", "Hello World!").build(); entity = ds.put(entity); entity = ds.get(key); System.out.println(entity); }

I started my Datastore Emulator on localhost:9999. Set that as the host when building the DatastoreOptions.

I've confirmed that the Emulator console shows requests are received and entities are persisted. I've also checked the data file (local_db.bin) and it shows the data (of course it is not a plain text file).

The one thing I don't know is - if there is a way to manage the local datastore using a browser interface. I could not find much documentation on how to administer the local datastore just like how we do the remote one from Cloud Console. Perhaps someone else can help on this.

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