无法通过本地服务器上的 Objectify 访问 App Engine 数据存储

Question

我正在尝试使用 Eclipse 在本地主机上运行应用引擎 spring 项目。我在控制台中收到以下错误。

Apr 23, 2018 4:01:04 PM com.google.auth.oauth2.ComputeEngineCredentials runningOnComputeEngine
WARNING: Failed to detect whether we are running on Google Compute Engine.
java.net.SocketException: Network is unreachable: connect
    at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:589)
    at sun.net.NetworkClient.doConnect(NetworkClient.java:175)
    at sun.net.www.http.HttpClient.openServer(HttpClient.java:463)
    at sun.net.www.http.HttpClient.openServer(HttpClient.java:558)
    at sun.net.www.http.HttpClient.<init>(HttpClient.java:242)
    at sun.net.www.http.HttpClient.New(HttpClient.java:339)
    at sun.net.www.http.HttpClient.New(HttpClient.java:357)
    at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:1220)
    at sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1156)
    at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:1050)
    at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:984)
    at com.google.api.client.http.javanet.NetHttpRequest.execute(NetHttpRequest.java:104)
    at com.google.api.client.http.HttpRequest.execute(HttpRequest.java:981)
    at com.google.auth.oauth2.ComputeEngineCredentials.runningOnComputeEngine(ComputeEngineCredentials.java:191)
    at com.google.auth.oauth2.DefaultCredentialsProvider.tryGetComputeCredentials(DefaultCredentialsProvider.java:270)
    at com.google.auth.oauth2.DefaultCredentialsProvider.getDefaultCredentialsUnsynchronized(DefaultCredentialsProvider.java:194)
    at com.google.auth.oauth2.DefaultCredentialsProvider.getDefaultCredentials(DefaultCredentialsProvider.java:112)
    at com.google.auth.oauth2.GoogleCredentials.getApplicationDefault(GoogleCredentials.java:127)
    at com.google.auth.oauth2.GoogleCredentials.getApplicationDefault(GoogleCredentials.java:100)
    at com.google.cloud.ServiceOptions.defaultCredentials(ServiceOptions.java:298)
    at com.google.cloud.ServiceOptions.<init>(ServiceOptions.java:272)
    at com.google.cloud.datastore.DatastoreOptions.<init>(DatastoreOptions.java:102)
    at com.google.cloud.datastore.DatastoreOptions.<init>(DatastoreOptions.java:35)
    ...

如何提供凭据以在本地主机中使用数据存储？当我访问数据存储时，我在控制台上得到以下信息。

2018-04-23 17:22:05.849:WARN:oejs.ServletHandler:qtp152005629-14: org.spring.framework.web.util.NestedServletException: Request processing failed; nested exception is com.google.cloud.datastore.DatastoreException: Unauthenticated.
Caused by: 
com.google.cloud.datastore.DatastoreException: Unauthenticated

Answer 1

Objectify v6 使用 Datastore SDK for Google Cloud Platform（您可以将其视为 GCP 的 "general purpose" SDK）。该 SDK 对云服务进行实际 API 调用，即使它是在本地运行也是如此。如果你想运行 tests/develop 针对本地数据存储，你需要做两件事之一。

选项一

不使用 GCP 数据存储 SDK，而是使用 App Engine SDK 的数据存储绑定。 Objectify 在 v6 中承诺使用 GCP SDK，但 v5 使用了 App Engine SDK。您可以降级到 v5，一切都会 "just work"。

选项二

如果您想继续使用 Objectify v6，您需要将额外的 gcloud 组件安装到运行本地数据存储模拟器，并且您需要设置一些环境变量。更多详细信息 here，但简短版本为：

安装并启动数据存储模拟器：

$ gcloud components install cloud-datastore-emulator
$ gcloud beta emulators datastore start

然后告诉您的应用程序在哪里可以找到它：

$ (gcloud beta emulators datastore env-init)

或者您可以手动设置相关的环境变量。在运行应用程序所在的机器上，按照 env-init 命令的输出指示设置环境变量和值。例如：

gcloud beta emulators datastore env-init
export DATASTORE_EMULATOR_HOST=localhost:8432
export DATASTORE_PROJECT_ID=my-project-id

无法通过本地服务器上的 Objectify 访问 App Engine 数据存储

Unable to access app engine datastore via Objectify on a local server

google-app-engine

objectify

google-cloud-datastore