解析JSON时Google云数据流Javascript UDF错误

我使用Pub/Sub-to-BigQuery来流式传输发送到Pub/Sub主题的JSON数据。通过数据流，我希望将数据展平，以匹配BigQuery模式，并对其进行流式处理

以下是数据流流程的Javascript UDF：

function transform(inJson) {
    var obj = JSON.parse(inJson);
    // variable declarations
    // ... 
    data['domain'] = obj['data']['domain']; // line 18
    ...

    return JSON.stringify(data);
}

我也试过：

data.domain = obj.data.domain;

我刚刚从中复制了这个示例，并对其进行了扩展，以平坦化JSON数据

以下是错误消息：

TypeError: Cannot read property "domain" from undefined in <eval> at line number 18

TypeError:无法从第18行中未定义的中读取属性“domain”

以及stacktrace：

javax.script.ScriptException: TypeError: Cannot read property "domain" from undefined in <eval> at line number 18
    at jdk.nashorn.api.scripting.NashornScriptEngine.throwAsScriptException(NashornScriptEngine.java:470)
    at jdk.nashorn.api.scripting.NashornScriptEngine.invokeImpl(NashornScriptEngine.java:392)
    at jdk.nashorn.api.scripting.NashornScriptEngine.invokeFunction(NashornScriptEngine.java:190)
    at com.google.cloud.teleport.templates.common.JavascriptTextTransformer$JavascriptRuntime.invoke(JavascriptTextTransformer.java:156)
    at com.google.cloud.teleport.templates.common.JavascriptTextTransformer$FailsafeJavascriptUdf$1.processElement(JavascriptTextTransformer.java:315)
    at com.google.cloud.teleport.templates.common.JavascriptTextTransformer$FailsafeJavascriptUdf$1$DoFnInvoker.invokeProcessElement(Unknown Source)
    at org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.SimpleDoFnRunner.invokeProcessElement(SimpleDoFnRunner.java:275)
    at org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.SimpleDoFnRunner.processElement(SimpleDoFnRunner.java:240)
    at org.apache.beam.runners.dataflow.worker.SimpleParDoFn.processElement(SimpleParDoFn.java:325)
    at org.apache.beam.runners.dataflow.worker.util.common.worker.ParDoOperation.process(ParDoOperation.java:44)
    at org.apache.beam.runners.dataflow.worker.util.common.worker.OutputReceiver.process(OutputReceiver.java:49)
    at org.apache.beam.runners.dataflow.worker.SimpleParDoFn$1.output(SimpleParDoFn.java:272)
    at org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.SimpleDoFnRunner.outputWindowedValue(SimpleDoFnRunner.java:309)
    at org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.SimpleDoFnRunner.access$700(SimpleDoFnRunner.java:77)
    at org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.SimpleDoFnRunner$DoFnProcessContext.output(SimpleDoFnRunner.java:621)
    at org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.SimpleDoFnRunner$DoFnProcessContext.output(SimpleDoFnRunner.java:609)
    at com.google.cloud.teleport.templates.PubSubToBigQuery$PubsubMessageToFailsafeElementFn.processElement(PubSubToBigQuery.java:412)
    at com.google.cloud.teleport.templates.PubSubToBigQuery$PubsubMessageToFailsafeElementFn$DoFnInvoker.invokeProcessElement(Unknown Source)
    at org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.SimpleDoFnRunner.invokeProcessElement(SimpleDoFnRunner.java:275)
    at org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.SimpleDoFnRunner.processElement(SimpleDoFnRunner.java:240)
    at org.apache.beam.runners.dataflow.worker.SimpleParDoFn.processElement(SimpleParDoFn.java:325)
    at org.apache.beam.runners.dataflow.worker.util.common.worker.ParDoOperation.process(ParDoOperation.java:44)
    at org.apache.beam.runners.dataflow.worker.util.common.worker.OutputReceiver.process(OutputReceiver.java:49)
    at org.apache.beam.runners.dataflow.worker.SimpleParDoFn$1.output(SimpleParDoFn.java:272)
    at org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.SimpleDoFnRunner.outputWindowedValue(SimpleDoFnRunner.java:309)
    at org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.SimpleDoFnRunner.access$700(SimpleDoFnRunner.java:77)
    at org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.SimpleDoFnRunner$DoFnProcessContext.output(SimpleDoFnRunner.java:621)
    at org.apache.beam.sdk.transforms.DoFnOutputReceivers$WindowedContextOutputReceiver.output(DoFnOutputReceivers.java:71)
    at org.apache.beam.sdk.transforms.MapElements$1.processElement(MapElements.java:122)
    at org.apache.beam.sdk.transforms.MapElements$1$DoFnInvoker.invokeProcessElement(Unknown Source)
    at org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.SimpleDoFnRunner.invokeProcessElement(SimpleDoFnRunner.java:275)
    at org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.SimpleDoFnRunner.processElement(SimpleDoFnRunner.java:240)
    at org.apache.beam.runners.dataflow.worker.SimpleParDoFn.processElement(SimpleParDoFn.java:325)
    at org.apache.beam.runners.dataflow.worker.util.common.worker.ParDoOperation.process(ParDoOperation.java:44)
    at org.apache.beam.runners.dataflow.worker.util.common.worker.OutputReceiver.process(OutputReceiver.java:49)
    at org.apache.beam.runners.dataflow.worker.util.common.worker.ReadOperation.runReadLoop(ReadOperation.java:201)
    at org.apache.beam.runners.dataflow.worker.util.common.worker.ReadOperation.start(ReadOperation.java:159)
    at org.apache.beam.runners.dataflow.worker.util.common.worker.MapTaskExecutor.execute(MapTaskExecutor.java:76)
    at org.apache.beam.runners.dataflow.worker.StreamingDataflowWorker.process(StreamingDataflowWorker.java:1233)
    at org.apache.beam.runners.dataflow.worker.StreamingDataflowWorker.access$1000(StreamingDataflowWorker.java:144)
    at org.apache.beam.runners.dataflow.worker.StreamingDataflowWorker$6.run(StreamingDataflowWorker.java:972)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
Caused by: <eval>:18 TypeError: Cannot read property "domain" from undefined
    at jdk.nashorn.internal.runtime.ECMAErrors.error(ECMAErrors.java:57)
    at jdk.nashorn.internal.runtime.ECMAErrors.typeError(ECMAErrors.java:213)
    at jdk.nashorn.internal.runtime.ECMAErrors.typeError(ECMAErrors.java:185)
    at jdk.nashorn.internal.runtime.ECMAErrors.typeError(ECMAErrors.java:172)
    at jdk.nashorn.internal.runtime.Undefined.get(Undefined.java:157)
    at jdk.nashorn.internal.scripts.Script$Recompilation$1$7667A$\^eval\_.transform(<eval>:18)
    at jdk.nashorn.internal.runtime.ScriptFunctionData.invoke(ScriptFunctionData.java:639)
    at jdk.nashorn.internal.runtime.ScriptFunction.invoke(ScriptFunction.java:494)
    at jdk.nashorn.internal.runtime.ScriptRuntime.apply(ScriptRuntime.java:393)
    at jdk.nashorn.api.scripting.ScriptObjectMirror.callMember(ScriptObjectMirror.java:199)
    at jdk.nashorn.api.scripting.NashornScriptEngine.invokeImpl(NashornScriptEngine.java:386)
    ... 42 more

javax.script.ScriptException:TypeError:无法从第18行中未定义的中读取属性“domain”
位于jdk.nashorn.api.scripting.NashornScriptEngine.throwAsScriptException（NashornScriptEngine.java:470）
位于jdk.nashorn.api.scripting.NashornScriptEngine.invokeImpl（NashornScriptEngine.java:392）
位于jdk.nashorn.api.scripting.NashornScriptEngine.invokeFunction（NashornScriptEngine.java:190）
位于com.google.cloud.teleport.templates.common.JavascriptTextTransformer$JavascriptRuntime.invoke（JavascriptTextTransformer.java:156）
位于com.google.cloud.teleport.templates.common.JavascriptTextTransformer$FailsafeJavascriptUdf$1.processElement（JavascriptTextTransformer.java:315）
位于com.google.cloud.teleport.templates.common.JavascriptTextTransformer$FailsafeJavascriptUdf$1$DoFnInvoker.invokeProcessElement（未知源）
位于org.apache.beam.runners.dataflow.worker.repacked.org.apache.beam.runners.core.simpledofnlunner.invokeproceselement（simpledofnlunner.java:275）
位于org.apache.beam.runners.dataflow.worker.repacked.org.apache.beam.runners.core.simpledofnlunner.processElement（simpledofnlunner.java:240）
位于org.apache.beam.runners.dataflow.worker.SimpleParDoFn.processElement（SimpleParDoFn.java:325）
位于org.apache.beam.runners.dataflow.worker.util.common.worker.ParDoOperation.process（ParDoOperation.java:44）
位于org.apache.beam.runners.dataflow.worker.util.common.worker.OutputReceiver.process（OutputReceiver.java:49）
位于org.apache.beam.runners.dataflow.worker.SimpleParDoFn$1.output（SimpleParDoFn.java:272）
位于org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.simpledofnlunner.outputWindowedValue（simpledofnlunner.java:309）
位于org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.simpledofnlunner.access$700（simpledofnlunner.java:77）
位于org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.simpledofnlunner$DoFnProcessContext.output（simpledofnlunner.java:621）
位于org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.simpledofnlunner$DoFnProcessContext.output（simpledofnlunner.java:609）
在com.google.cloud.teleport.templates.pubsubotbigquery$pubsubsubmessageofailsafelementfn.processElement（pubsubotbigquery.java:412）
在com.google.cloud.teleport.templates.PubSubsubBigQuery$PubSubMessageOfailSafeElementfn$DoFnInvoker.invokeProcessElement（未知源）
位于org.apache.beam.runners.dataflow.worker.repacked.org.apache.beam.runners.core.simpledofnlunner.invokeproceselement（simpledofnlunner.java:275）
位于org.apache.beam.runners.dataflow.worker.repacked.org.apache.beam.runners.core.simpledofnlunner.processElement（simpledofnlunner.java:240）
位于org.apache.beam.runners.dataflow.worker.SimpleParDoFn.processElement（SimpleParDoFn.java:325）
位于org.apache.beam.runners.dataflow.worker.util.common.worker.ParDoOperation.process（ParDoOperation.java:44）
位于org.apache.beam.runners.dataflow.worker.util.common.worker.OutputReceiver.process（OutputReceiver.java:49）
位于org.apache.beam.runners.dataflow.worker.SimpleParDoFn$1.output（SimpleParDoFn.java:272）
位于org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.simpledofnlunner.outputWindowedValue（simpledofnlunner.java:309）
位于org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.simpledofnlunner.access$700（simpledofnlunner.java:77）
位于org.apache.beam.runners.dataflow.worker.repackaged.org.apache.beam.runners.core.simpledofnlunner$DoFnProcessContext.output（simpledofnlunner.java:621）
位于org.apache.beam.sdk.transforms.dofnOutputReceiver$WindowedContextOutputReceiver.output（dofnOutputReceiver.java:71）
位于org.apache.beam.sdk.transforms.MapElements$1.processElement（MapElements.java:122）
位于org.apache.beam.sdk.transforms.MapElements$1$DoFnInvoker.invokeProcessElement（未知源）
位于org.apache.beam.runners.dataflow.worker.repacked.org.apache.beam.runners.core.simpledofnlunner.invokeproceselement（simpledofnlunner.java:275）
位于org.apache.beam.runners.dataflow.worker.repacked.org.apache.beam.runners.core.simpledofnlunner.processElement（simpledofnlunner.java:240）
位于org.apache.beam.runners.dataflow.worker.SimpleParDoFn.processElement（SimpleParDoFn.java:325）
位于org.apache.beam.runners.dataflow.worker.util.common.worker.ParDoOperation.process（ParDoOperation.java:44）
位于org.apache.beam.runners.dataflow.worker.util.common.worker.OutputReceiver.process（OutputReceiver.java:49）
位于org.apache.beam.runners.dataflow.worker.util.common.worker.ReadOperation.runReadLoop（ReadOperation.java:201）
位于org.apache.beam.runners.dataflow.worker.util.common.worker.ReadOperation.start（ReadOperation.java:159）
位于org.apache.beam.runners.dataflow.worker.util.common.worker.MapTaskExecutor.execute（MapTaskExecutor.java:76）
位于org.apache.beam.runners.dataflow.worker.StreamingDataflowWorker.process（StreamingDataflowWorker.java:1233）
位于org.apache.beam.runners.dataflow.worker.StreamingDataflowWorker.access$1000（StreamingDataflowWorker.java:144）
位于org.apache.beam.runners.dataflow.worker.StreamingDataflowWorker$6.run（StreamingDataflowWorker.java:972）
位于java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1142）
位于java.util.concurrent.ThreadPoolExecutor$Worker.run（ThreadPoolExecutor.java:617）
在java.l
data['domain'] = obj['data']['domain']; // line 18

TypeError: Cannot read property "domain" from undefined in <eval> at line number 18

{"name":"Sam","age":21}