Program crashes trying to read JSON file
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Program crashes trying to read JSON file
 
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Hello all, We are using Flink 0.7 and trying to read a large JSON file, reading some fields into a flink (3-tuple based) dataset, then performing some operations. We encountered the following runtime error: [QUOTE] Error: The main method caused an error. org.apache.flink.client.program.ProgramInvocationException: The main method caused an error. at org.apache.flink.client.program.PackagedProgram.callMainMethod(PackagedProgram.java:404) at org.apache.flink.client.program.PackagedProgram.invokeInteractiveModeForExecution(PackagedProgram.java:307) at org.apache.flink.client.program.Client.run(Client.java:244) at org.apache.flink.client.CliFrontend.executeProgram(CliFrontend.java:347) at org.apache.flink.client.CliFrontend.run(CliFrontend.java:334) at org.apache.flink.client.CliFrontend.parseParameters(CliFrontend.java:1001) at org.apache.flink.client.CliFrontend.main(CliFrontend.java:1025) Caused by: org.apache.flink.api.java.aggregation.UnsupportedAggregationTypeException: The type java.lang.String has currently not supported for built-in sum aggregations. at org.apache.flink.api.java.aggregation.SumAggregationFunction$SumAggregationFunctionFactory.createAggregationFunction(SumAggregationFunction.java:186) at org.apache.flink.api.java.operators.AggregateOperator.<init>(AggregateOperator.java:109) at org.apache.flink.api.java.operators.UnsortedGrouping.aggregate(UnsortedGrouping.java:61) at org.apache.flink.api.java.operators.UnsortedGrouping.sum(UnsortedGrouping.java:72) at org.apache.flink.examples.java.wordcount.WordCount.main(WordCount.java:75) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.apache.flink.client.program.PackagedProgram.callMainMethod(PackagedProgram.java:389) ... 6 more [/QUOTE] The code snippet that could have caused this error (i.e. that we edited) is the following [CODE] import org.apache.flink.api.java.tuple.Tuple3; import org.apache.flink.util.Collector; import org.apache.flink.api.java.DataSet; import org.apache.flink.api.java.ExecutionEnvironment; import org.apache.flink.streaming.connectors.json.JSONParseFlatMap; import org.apache.sling.commons.json.JSONException; ... public static void main(String[] args) throws Exception { if(!parseParameters(args)) { return; } // set up the execution environment final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment(); // get input data DataSet<String> text = getTextDataSet(env); DataSet<Tuple3<Integer, String, String>> counts = // split up the lines in pairs (3-tuples) containing: (timestamp,uuid,event) text.flatMap(new SelectDataFlatMap()) // group by the tuple field "0" and sum up tuple field "1" .groupBy(2) .sum(2); // emit result if(fileOutput) { counts.writeAsCsv(outputPath, "\n", " "); } else { counts.print(); } // execute program env.execute("Weblogs Programme"); } ... public static class SelectDataFlatMap extends JSONParseFlatMap<String, Tuple3<Integer, String, String>> { @Override public void flatMap(String value, Collector<Tuple3<Integer, String, String>> out) throws Exception { try { out.collect(new Tuple3<Integer, String, String>( getInt(value, "timestamp"), getString(value, "uuid"), getString(value, "event"))); } catch (JSONException e) { System.err.println("Field not found"); } } } [/CODE] [QUOTE] Error: The main method caused an error. org.apache.flink.client.program.ProgramInvocationException: The main method caused an error. at org.apache.flink.client.program.PackagedProgram.callMainMethod(PackagedProgram.java:404) at org.apache.flink.client.program.PackagedProgram.invokeInteractiveModeForExecution(PackagedProgram.java:307) at org.apache.flink.client.program.Client.run(Client.java:244) at org.apache.flink.client.CliFrontend.executeProgram(CliFrontend.java:347) at org.apache.flink.client.CliFrontend.run(CliFrontend.java:334) at org.apache.flink.client.CliFrontend.parseParameters(CliFrontend.java:1001) at org.apache.flink.client.CliFrontend.main(CliFrontend.java:1025) Caused by: org.apache.flink.api.java.aggregation.UnsupportedAggregationTypeException: The type java.lang.String has currently not supported for built-in sum aggregations. at org.apache.flink.api.java.aggregation.SumAggregationFunction$SumAggregationFunctionFactory.createAggregationFunction(SumAggregationFunction.java:186) at org.apache.flink.api.java.operators.AggregateOperator.<init>(AggregateOperator.java:109) at org.apache.flink.api.java.operators.UnsortedGrouping.aggregate(UnsortedGrouping.java:61) at org.apache.flink.api.java.operators.UnsortedGrouping.sum(UnsortedGrouping.java:72) at org.apache.flink.examples.java.wordcount.WordCount.main(WordCount.java:75) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.apache.flink.client.program.PackagedProgram.callMainMethod(PackagedProgram.java:389) ... 6 more [/QUOTE] The JSON file is of the following nature, with a 2-level hierarchy for one field: [JSON] {timestamp: <a href="callto:1397731764" data-mce-href="callto:1397731764">1397731764 payload: {product: Younited uuid: 754726549cec3968a60ffffa2f8ccdc1da27e57a01af4bb2b11841803a25eadd platform: native version: 6aa54aca95fb1b8ef2290136ab12df2e4b011241 type: can-usage-v1 event: General,Login,Success}} {timestamp: <a href="callto:1397731765" data-mce-href="callto:1397731765">1397731765 payload: {product: Younited uuid: e0b3dad557ca77dc035fd22d1e8608c4248526ab9318a85637dbf88228a4034e platform: native version: 7b4b767060b62537b63c5d10d911870a14d2b84e type: can-usage-v1 event: General,App,Opened}} [/JSON] Thanks in advance for helping us to understand where we are going wrong. Anirvan |
Re: Program crashes trying to read JSON file
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Hi,
the problems seems to be originating from this statement: text.flatMap(new SelectDataFlatMap()) // group by the tuple field "0" and sum up tuple field "1" .groupBy(2) .sum(2); The indices in these operations are 0-based. What do you expect the result of this operation might be? The aggregate operations only work on number data types right now. Regards, Aljoscha On Tue, Nov 25, 2014 at 4:55 PM, Anirvan BASU <[hidden email]> wrote: > Hello all, > > We are using Flink 0.7 and trying to read a large JSON file, reading some > fields into a flink (3-tuple based) dataset, then performing some > operations. > > We encountered the following runtime error: > > [QUOTE] > Error: The main method caused an error. > org.apache.flink.client.program.ProgramInvocationException: The main method > caused an error. > at > org.apache.flink.client.program.PackagedProgram.callMainMethod(PackagedProgram.java:404) > at > org.apache.flink.client.program.PackagedProgram.invokeInteractiveModeForExecution(PackagedProgram.java:307) > at org.apache.flink.client.program.Client.run(Client.java:244) > at > org.apache.flink.client.CliFrontend.executeProgram(CliFrontend.java:347) > at org.apache.flink.client.CliFrontend.run(CliFrontend.java:334) > at > org.apache.flink.client.CliFrontend.parseParameters(CliFrontend.java:1001) > at org.apache.flink.client.CliFrontend.main(CliFrontend.java:1025) > Caused by: > org.apache.flink.api.java.aggregation.UnsupportedAggregationTypeException: > The type java.lang.String has currently not supported for built-in sum > aggregations. > at > org.apache.flink.api.java.aggregation.SumAggregationFunction$SumAggregationFunctionFactory.createAggregationFunction(SumAggregationFunction.java:186) > at > org.apache.flink.api.java.operators.AggregateOperator.<init>(AggregateOperator.java:109) > at > org.apache.flink.api.java.operators.UnsortedGrouping.aggregate(UnsortedGrouping.java:61) > at > org.apache.flink.api.java.operators.UnsortedGrouping.sum(UnsortedGrouping.java:72) > at > org.apache.flink.examples.java.wordcount.WordCount.main(WordCount.java:75) > at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) > at > sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) > at > sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) > at java.lang.reflect.Method.invoke(Method.java:606) > at > org.apache.flink.client.program.PackagedProgram.callMainMethod(PackagedProgram.java:389) > ... 6 more > [/QUOTE] > > > > The code snippet that could have caused this error (i.e. that we edited) is > the following > > [CODE] > > import org.apache.flink.api.java.tuple.Tuple3; > import org.apache.flink.util.Collector; > import org.apache.flink.api.java.DataSet; > import org.apache.flink.api.java.ExecutionEnvironment; > import org.apache.flink.streaming.connectors.json.JSONParseFlatMap; > import org.apache.sling.commons.json.JSONException; > ... > > public static void main(String[] args) throws Exception { > > if(!parseParameters(args)) { > return; > } > > // set up the execution environment > final ExecutionEnvironment env = > ExecutionEnvironment.getExecutionEnvironment(); > > // get input data > DataSet<String> text = getTextDataSet(env); > > DataSet<Tuple3<Integer, String, String>> counts = > // split up the lines in pairs (3-tuples) containing: > (timestamp,uuid,event) > text.flatMap(new SelectDataFlatMap()) > // group by the tuple field "0" and sum up tuple field "1" > .groupBy(2) > .sum(2); > > // emit result > if(fileOutput) { > counts.writeAsCsv(outputPath, "\n", " "); > } else { > counts.print(); > } > > // execute program > env.execute("Weblogs Programme"); > } > > ... > > public static class SelectDataFlatMap extends > JSONParseFlatMap<String, Tuple3<Integer, String, String>> { > > @Override > public void flatMap(String value, Collector<Tuple3<Integer, String, > String>> out) > throws Exception { > try { > out.collect(new Tuple3<Integer, String, String>( > getInt(value, "timestamp"), > getString(value, "uuid"), > getString(value, "event"))); > } catch (JSONException e) { > System.err.println("Field not found"); > } > } > } > > [/CODE] > > > > [QUOTE] > Error: The main method caused an error. > org.apache.flink.client.program.ProgramInvocationException: The main method > caused an error. > at > org.apache.flink.client.program.PackagedProgram.callMainMethod(PackagedProgram.java:404) > at > org.apache.flink.client.program.PackagedProgram.invokeInteractiveModeForExecution(PackagedProgram.java:307) > at org.apache.flink.client.program.Client.run(Client.java:244) > at > org.apache.flink.client.CliFrontend.executeProgram(CliFrontend.java:347) > at org.apache.flink.client.CliFrontend.run(CliFrontend.java:334) > at > org.apache.flink.client.CliFrontend.parseParameters(CliFrontend.java:1001) > at org.apache.flink.client.CliFrontend.main(CliFrontend.java:1025) > Caused by: > org.apache.flink.api.java.aggregation.UnsupportedAggregationTypeException: > The type java.lang.String has currently not supported for built-in sum > aggregations. > at > org.apache.flink.api.java.aggregation.SumAggregationFunction$SumAggregationFunctionFactory.createAggregationFunction(SumAggregationFunction.java:186) > at > org.apache.flink.api.java.operators.AggregateOperator.<init>(AggregateOperator.java:109) > at > org.apache.flink.api.java.operators.UnsortedGrouping.aggregate(UnsortedGrouping.java:61) > at > org.apache.flink.api.java.operators.UnsortedGrouping.sum(UnsortedGrouping.java:72) > at > org.apache.flink.examples.java.wordcount.WordCount.main(WordCount.java:75) > at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) > at > sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) > at > sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) > at java.lang.reflect.Method.invoke(Method.java:606) > at > org.apache.flink.client.program.PackagedProgram.callMainMethod(PackagedProgram.java:389) > ... 6 more > [/QUOTE] > > > The JSON file is of the following nature, with a 2-level hierarchy for one > field: > [JSON] > {timestamp: 1397731764 payload: {product: Younited uuid: > 754726549cec3968a60ffffa2f8ccdc1da27e57a01af4bb2b11841803a25eadd > platform: native version: 6aa54aca95fb1b8ef2290136ab12df2e4b011241 > type: can-usage-v1 event: General,Login,Success}} > {timestamp: 1397731765 payload: {product: Younited uuid: > e0b3dad557ca77dc035fd22d1e8608c4248526ab9318a85637dbf88228a4034e > platform: native version: 7b4b767060b62537b63c5d10d911870a14d2b84e > type: can-usage-v1 event: General,App,Opened}} > [/JSON] > > > > Thanks in advance for helping us to understand where we are going wrong. > > Anirvan |
Re: Program crashes trying to read JSON file
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In reply to this post by Anirvan BASU
Very quickly, it seems you are trying to sum on Strings Caused by: org.apache.flink.api.java. aggregation.UnsupportedAggregationTypeException: The type java.lang.String has currently not supported for built-in sum aggregations. Check your tuple types and be sure that you are not summing on strings. 2014-11-25 16:55 GMT+01:00 Anirvan BASU <[hidden email]>:
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Re: Program crashes trying to read JSON file
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Thanks to Aljoscha and Stefano for pointing out the flaw. We corrected the issue as follows: [CODE] import org.apache.flink.api.java.tuple.Tuple4; import org.apache.flink.util.Collector; import org.apache.flink.api.java.DataSet; import org.apache.flink.api.java.ExecutionEnvironment; import org.apache.flink.streaming.connectors.json.JSONParseFlatMap; import org.apache.sling.commons.json.JSONException; ... public static void main(String[] args) throws Exception { if(!parseParameters(args)) { return; } // set up the execution environment final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment(); // get input data DataSet<String> text = getTextDataSet(env); DataSet<Tuple4<Integer, String, String, Integer>> counts = // split up the lines in pairs (4-tuples) containing: (timestamp,uuid,event,count) text.flatMap(new SelectDataFlatMap()) // group by the tuple field "1" (an event - string) and sum up tuple field "3" (integer - value 1) .groupBy(1) .sum(3); // emit result if(fileOutput) { counts.writeAsCsv(outputPath, "\n", " "); } else { counts.print(); } // execute program env.execute("Weblogs Programme"); } ... public static class SelectDataFlatMap extends JSONParseFlatMap<String, Tuple4<Integer, String, String, Integer>> { public void flatMap(String value, Collector<Tuple4<Integer, String, String, Integer>> record) throws Exception { try { record.collect(new Tuple4<Integer, String, String, Integer>( getInt(value, "timestamp"), getString(value, "uuid"), getString(value, "event"), 1)); } catch (JSONException e) { System.err.println("Field not found"); } } } [/CODE] However, this time the issue was different. The programme executed correctly till status FINISHED. However, there was no output :-(( i.e. For each Task Manager, an empty file is written. When we checked further about the input text file that is read using env.readTextFile() we find that instead of a text string (full text dataset) only a small string is written! Worse still ! this string value sometimes remains the same over multiple runs of the programme .... Is this natural ? Is this just the handle to the file or the dataset ? Is the Collector() working correctly also ? Note : The actual JSON file (i.e. the text file that should be read) is of the following nature, with a 2-level hierarchy for one field: [JSON] {timestamp: <a href="callto:1397731764" target="_blank" data-mce-href="callto:1397731764">1397731764 payload: {product: Younited uuid: 754726549cec3968a60ffffa2f8ccdc1da27e57a01af4bb2b11841803a25eadd platform: native version: 6aa54aca95fb1b8ef2290136ab12df2e4b011241 type: can-usage-v1 event: General,Login,Success}} {timestamp: <a href="callto:1397731765" target="_blank" data-mce-href="callto:1397731765">1397731765 payload: {product: Younited uuid: e0b3dad557ca77dc035fd22d1e8608c4248526ab9318a85637dbf88228a4034e platform: native version: 7b4b767060b62537b63c5d10d911870a14d2b84e type: can-usage-v1 event: General,App,Opened}} [/JSON] So now again, we are confused if we are doing it correctly :-(( Thanks in advance for helping us to understand where we are going wrong. Anirvan From: "Stefano Bortoli" <[hidden email]> |
Re: Program crashes trying to read JSON file
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You can output your results in different ways. If all you need is to write a file, I normally use the writeAsText method (however, there is the writeAsCSV, writeAsFormattedText. Of write according to your custom FileOutputFormat. datasetToPrint.writeAsText("/path/to/file/with/permission", WriteMode.OVERWRITE);Stefano 2014-11-25 22:04 GMT+01:00 Anirvan BASU <[hidden email]>:
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Re: Program crashes trying to read JSON file
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Ciao Stefano ! Thanks for this early morning information, very helpful. Yes, for outputting the data we are using WriteAsCSV which is stable over different versions of Flink. Our current concern is "reading" a JSON file into a dataset. As you can see, we have a simple 2-level JSON hierarchy that can be easily mapped to a fixed-column CSV. But the place we are stuck at currently is in reading the file correctly into a tuple-based dataset in memory. Once this is achieved, the rest will be fairly simple dataset transformations. As you can see from the pasted code, we used functions developed from the stream connector for our purposes. (Thanks to Gyula and Marton for that information) If reading a JSON file using functions already developed is not possible then we will have to develop some custom functions on hardcore string operations to do the same. That would be like reinventing the wheel ... :-(( Any advice in this regard will be highly appreciated. Thanks in advance to all, Anirvan From: "Stefano Bortoli" <[hidden email]> |
Re: Program crashes trying to read JSON file
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Hi Anirvan, The CSVInputFormat works with two delimiters, a record delimiter and a field delimiter. The input data is split at the record delimiter into records. Each record is split along the field delimiters into several fields. The number and type of fields must be constant. There is not logic to handle nested data. Looking at your data, I assume that the newline ('\n') character is the record delimiter. However due to the nested structure of your data, I don't see a valid field delimiter. If you have this input: {timestamp: <a tabindex="-1" href="callto:1397731764" target="_parent">1397731764 payload: {product: Younited uuid: 754726549cec3968a60ffffa2f8ccdc1da27e57a01af4bb2b11841803a25eadd platform: native version: 6aa54aca95fb1b8ef2290136ab12df2e4b011241 type: can-usage-v1 event: General,Login,Success}} Splitting along the field delimiter tab ('\t') would result in 7 String fields: - {timestamp: <a tabindex="-1" href="callto:1397731764" target="_parent">1397731764 - payload: {product: Younited - uuid: 754726549cec3968a60ffffa2f8ccdc1da27e57a01af4bb2b11841803a25eadd - platform: native - version: 6aa54aca95fb1b8ef2290136ab12df2e4b011241 - type: can-usage-v1 - event: General,Login,Success}} I guess this is not exactly what you want (curly braces, field names, etc.). The best way to handle JSON data right now is to have the records delimited by a character such as newline, read the data line-wise with the TextInputFormat, and use custom parse logic in a MapFunction. There you can also use JSON libraries (make sure they work thread-safe!). Best, Fabian 2014-11-26 9:01 GMT+01:00 Anirvan BASU <[hidden email]>:
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Re: Program crashes trying to read JSON file
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In reply to this post by Anirvan BASU
There must be something simple mixed up somewhere. The string output from your previous mail suggests that the output is the name of the data reading operator object. Not sure how you achieved that, but that is pretty mixed up. My gut feeling is that you call "toString()" on a DataSet somewhere and use that as actual data. Something like DataSet<String> text = env.fromElements(env.readTextFile(...).toString()) Reading JSON entries as strings (assuming they contain no linebreaks) and extracting fields is one of the "hello world" examples, there should be no strange surprises. I would have a look at examples like WordCount and check where you use different types of opetations. Btw: I would look into the Jackson library for json parsing and field extraction. Very easy to use, good performance. Am 26.11.2014 09:01 schrieb "Anirvan BASU" <[hidden email]>:
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Re: Program crashes trying to read JSON file
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In reply to this post by Fabian Hueske
Dear Fabian, Thanks for your meticulous analysis - awesome ! deutsche Qualität, selbstverstandlich !!! yes indeed, you are right about the String outputs that would be produced. I understand that a custom parse logic in a Map function is definitely necessary. I was trying to use the implementation used here : https://github.com/apache/incubator-flink/blob/release-0.7.0/flink-addons/flink-streaming/flink-streaming-connectors/src/main/java/org/apache/flink/streaming/connectors/twitter/TwitterStreaming.java#L52-73 It was suggested to me by Marton and Gyula, and I adapted it for my simple case of non-Streaming ... Question : would there be any difference in output, between the streaming and non-streaming cases, from the functions getInt() or getString() - these are the functions that actually do the extraction job, don't they ? However, if the above does not really work, then I will need to revert to some "hardcore" sub-string extraction specific to my case :-(( Thanks so much for your advice and support ! Anirvan From: "Fabian Hueske" <[hidden email]> |
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