Hi, I'm writing a custom `SourceFunction` which wraps an underlying `InputFormatSourceFunction`. When I try to use this `SourceFunction` in a stream (via `env.addSource` and a subsequent sink) I get errors related to the `InputSplitAssigner` not being initialized for a particular vertex ID. Full error here[1].
I believe the underlying error is related to this[0] call to `instanceof InputFormatSourceFunction`. *My questions*: 1. how can I wrap a `InputFormatSourceFunction` which avoids this error? Am I missing a chunk of the API covering this? 2. is the error I'm experience related to that casting call? If so, would ya'll be open to a PR which adds an interface one can extend which will set the input format in the stream graph? Or is there a preferred way of achieving this? Thanks! Aaron Levin [0] https://github.com/apache/flink/blob/release-1.6/flink-streaming-java/src/main/java/org/apache/flink/streaming/api/graph/StreamGraphGenerator.java#L480 [1] java.lang.RuntimeException: Could not retrieve next input split. at org.apache.flink.streaming.api.functions.source.InputFormatSourceFunction$1.hasNext(InputFormatSourceFunction.java:157) at org.apache.flink.streaming.api.functions.source.InputFormatSourceFunction.open(InputFormatSourceFunction.java:71) at REDACTED at org.apache.flink.api.common.functions.util.FunctionUtils.openFunction(FunctionUtils.java:36) at org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator.open(AbstractUdfStreamOperator.java:102) at org.apache.flink.streaming.runtime.tasks.StreamTask.openAllOperators(StreamTask.java:424) at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:290) at org.apache.flink.runtime.taskmanager.Task.run(Task.java:711) at java.lang.Thread.run(Thread.java:748) Caused by: org.apache.flink.runtime.jobgraph.tasks.InputSplitProviderException: Requesting the next input split failed. at org.apache.flink.runtime.taskexecutor.rpc.RpcInputSplitProvider.getNextInputSplit(RpcInputSplitProvider.java:69) at org.apache.flink.streaming.api.functions.source.InputFormatSourceFunction$1.hasNext(InputFormatSourceFunction.java:155) ... 8 more Caused by: java.util.concurrent.ExecutionException: java.lang.Exception: No InputSplitAssigner for vertex ID cbc357ccb763df2852fee8c4fc7d55f2 at java.util.concurrent.CompletableFuture.reportGet(CompletableFuture.java:357) at java.util.concurrent.CompletableFuture.get(CompletableFuture.java:1915) at org.apache.flink.runtime.taskexecutor.rpc.RpcInputSplitProvider.getNextInputSplit(RpcInputSplitProvider.java:61) ... 9 more Caused by: java.lang.Exception: No InputSplitAssigner for vertex ID cbc357ccb763df2852fee8c4fc7d55f2 at org.apache.flink.runtime.jobmaster.JobMaster.requestNextInputSplit(JobMaster.java:575) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.flink.runtime.rpc.akka.AkkaRpcActor.handleRpcInvocation(AkkaRpcActor.java:247) ...
