本地 Pubsub 模拟器不适用于 Dataflow

Question

我正在 Java 中开发 Dataflow，输入来自 Pubsub。后来，我看到了关于如何使用本地 Pubsub 模拟器的指南 here，这样我就不需要部署到 GCP 来进行测试了。

这是我的简单代码：

private interface Options extends PipelineOptions, PubsubOptions, StreamingOptions {

    @Description("Pub/Sub topic to read messages from")
    String getTopic();
    void setTopic(String topic);

    @Description("Pub/Sub subscription to read messages from")
    String getSubscription();
    void setSubscription(String subscription);

    @Description("Local file output")
    String getOutput();
    void setOutput(String output);
}

public static void main(String[] args) {

    Options options = PipelineOptionsFactory
            .fromArgs(args)
            .withValidation()
            .as(Options.class);
    options.setStreaming(true);
    options.setPubsubRootUrl("localhost:8085");

    Pipeline pipeline = Pipeline.create(options);
    pipeline
        .apply("IngestFromPubsub", PubsubIO.readStrings().fromTopic(options.getTopic()))
        // other .apply's

    pipeline.run();

}

我能够按照指南进行操作，包括我需要使用示例 Python 代码来创建主题、订阅、发布者甚至发布消息的部分。当我使用 Python 代码与 Pubsub 模拟器交互时，我注意到命令行中的消息 Detected HTTP/2 connection 我运行模拟器：

Executing: cmd /c C:\...\google-cloud-sdk\platform\pubsub-emulator\bin\cloud-pubsub-emulator.bat --host=localhost --port=8085
[pubsub] This is the Google Pub/Sub fake.
[pubsub] Implementation may be incomplete or differ from the real system.
[pubsub] Apr 10, 2020 3:33:26 PM com.google.cloud.pubsub.testing.v1.Main main
[pubsub] INFO: IAM integration is disabled. IAM policy methods and ACL checks are not supported
[pubsub] Apr 10, 2020 3:33:26 PM io.gapi.emulators.netty.NettyUtil applyJava7LongHostnameWorkaround
[pubsub] INFO: Unable to apply Java 7 long hostname workaround.
[pubsub] Apr 10, 2020 3:33:27 PM com.google.cloud.pubsub.testing.v1.Main main
[pubsub] INFO: Server started, listening on 8085
[pubsub] Apr 10, 2020 3:34:38 PM io.gapi.emulators.grpc.GrpcServer operationComplete
[pubsub] INFO: Adding handler(s) to newly registered Channel.
[pubsub] Apr 10, 2020 3:34:38 PM io.gapi.emulators.netty.HttpVersionRoutingHandler channelRead
[pubsub] INFO: Detected HTTP/2 connection.
[pubsub] Apr 10, 2020 3:34:52 PM io.gapi.emulators.grpc.GrpcServer operationComplete
[pubsub] INFO: Adding handler(s) to newly registered Channel.
[pubsub] Apr 10, 2020 3:34:52 PM io.gapi.emulators.netty.HttpVersionRoutingHandler channelRead
[pubsub] INFO: Detected HTTP/2 connection.

我compiled/run Eclipse中的代码使用Dataflow Pipeline 运行配置，但是我遇到了问题。

Exception in thread "main" org.apache.beam.sdk.Pipeline$PipelineExecutionException: java.lang.RuntimeException: Failed to create subscription: 
...
Caused by: java.lang.RuntimeException: Failed to create subscription: 
    at org.apache.beam.sdk.io.gcp.pubsub.PubsubUnboundedSource.createRandomSubscription(PubsubUnboundedSource.java:1427)
...
Caused by: java.lang.IllegalArgumentException: java.net.MalformedURLException: unknown protocol: localhost
...
Caused by: java.net.MalformedURLException: unknown protocol: localhost

当我尝试在行 options.setPubsubRootUrl("localhost:8085") 中添加 http 时，我得到一个无限重复的异常：

com.google.api.client.http.HttpRequest execute
WARNING: exception thrown while executing request
java.net.ConnectException: Connection refused: connect
    at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
    at java.net.PlainSocketImpl.connect(Unknown Source)
    at java.net.SocksSocketImpl.connect(Unknown Source)

它似乎到达了 Pubsub 模拟器，但无法作为命令行连接，我运行模拟器也无限地生成这个：

[pubsub] Apr 10, 2020 3:49:30 PM io.gapi.emulators.grpc.GrpcServer operationComplete
[pubsub] INFO: Adding handler(s) to newly registered Channel.
[pubsub] Apr 10, 2020 3:49:30 PM io.gapi.emulators.netty.HttpVersionRoutingHandler channelRead
[pubsub] INFO: Detected non-HTTP/2 connection.

如何让我的数据流与 Pubsub 模拟器一起工作？

Answer 1

您正在尝试使用 Beam 2.5 SDK 的数据流分支从 Beam Direct Runner 连接到 Pubsub 模拟器。数据流 2.5 SDK 和 Eclipse 插件已于 2019 年 6 月 6 日弃用。但是这应该有效。

如您所见，您需要在 Beam 中为 PubsubRootUrl 添加前缀 'http://'。您看到的第二个问题表明 localhost:8085 上没有任何内容在侦听。这可能是因为实际上有 2 个本地主机：IPv4 和 IPv6。 Pubsub 模拟器仅侦听 IPv4，Windows 首先尝试 IPv6。尝试将 localhost 替换为 127.0.0.1 以强制使用 IPv4。你应该这样结束：

options.setPubsubRootUrl("http://127.0.0.1:8085")

本地 Pubsub 模拟器不适用于 Dataflow

Local Pubsub Emulator won't work with Dataflow

java

eclipse

google-cloud-pubsub

google-cloud-dataflow

apache-beam