当使用本地直接跑步者时，Apache Beam返回“输入值不得以任何方式变异。”

I wrote an Apache Beam DoFn

我写了一个Apache Beam DoFn

static class FillLocation extends DoFn<TrackingRequest, TrackingRequest> {
        @ProcessElement
        public void processElement(ProcessContext c) {    
            TrackingRequest rq = c.element();
            rq.location = getLocationFromIP(rq.IP);         
            c.output(rq);
        }
}

And it gave me this error when testing it locally PTransform .. illegaly mutated value .. of class.....

当它在本地测试它时，它给了我这个错误PTransform ..非法变异值...类.....

 Input values must not be mutated in any way.
    at org.apache.beam.runners.direct.ImmutabilityEnforcementFactory$ImmutabilityCheckingEnforcement.verifyUnmodified(ImmutabilityEnforcementFactory.java:96)
    at org.apache.beam.runners.direct.ImmutabilityEnforcementFactory$ImmutabilityCheckingEnforcement.afterElement(ImmutabilityEnforcementFactory.java:71)
    at org.apache.beam.runners.direct.TransformExecutor.processElements(TransformExecutor.java:149)
    at org.apache.beam.runners.direct.TransformExecutor.run(TransformExecutor.java:107)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)

1 个解决方案

#1

Your function modified the location field of the input TrackingRequest element. This is not allowed by the Dataflow.

您的函数修改了输入TrackingRequest元素的位置字段。 Dataflow不允许这样做。

The doc says:

医生说：

The current element of the input PCollection is returned by c.element(). It should be considered immutable. The Dataflow runtime will not mutate the element, so it is safe to cache, etc. The element should not be mutated by any of the DoFn methods, because it may be cached elsewhere, retained by the Dataflow runtime, or used in other unspecified ways.

输入PCollection的当前元素由c.element（）返回。它应该被认为是不可改变的。 Dataflow运行时不会改变元素，因此可以安全地进行缓存等。任何DoFn方法都不应该突变该元素，因为它可以缓存在其他地方，由Dataflow运行时保留，或者以其他未指定的方式使用。

You can create a copy of the input element, modify the field, and send the copy out as output.

您可以创建输入元素的副本，修改字段，并将副本作为输出发送出去。

#1