Uploaded image for project: 'Beam'
  1. Beam
  2. BEAM-10030

Add CSVIO for Java SDK

Details

    • New Feature
    • Status: Triage Needed
    • P3
    • Resolution: Unresolved
    • None
    • None
    • io-ideas, io-java-files
    • None

    Description

      Apache Beam has TextIO class which can read text based files line by line, delimited by either a carriage return, newline, or a carriage return and a newline. This approach does not support CSV files which have records that span multiple lines. This is because there could be fields where there is a newline inside the double quotes.

      This Stackoverflow question is relevant for a feature that should be added to Apache Beam: https://stackoverflow.com/questions/51439189/how-to-read-large-csv-with-beam

      I can think of two libraries we could use for handling CSV files. The first one is using Apache Commons CSV library. Here is some example code which can use CSVRecord class for reading and writing CSV records:

      PipelineOptions options = PipelineOptionsFactory.create();
      Pipeline pipeline = Pipeline.create(options);
      PCollection<CSVRecord> records = pipeline.apply("ReadCSV", CSVIO.read().from("input.csv"));
      records.apply("WriteCSV", CSVIO.write().to("output.csv"));

      Another library we could use is Jackson CSV, which allows users to specify schemas for the columns: https://github.com/FasterXML/jackson-dataformats-text/tree/master/csv

      The crux of the problem is this: can we read and write large CSV files in parallel, by splitting the records and distribute it to many workers? If so, would it be good to have a feature where Apache Beam supports reading/writing CSV files?

      Attachments

        1. CSVSource.java
          3 kB
          Saurabh Joshi

        Activity

          People

            Unassigned Unassigned
            auroranil Saurabh Joshi
            Votes:
            0 Vote for this issue
            Watchers:
            4 Start watching this issue

            Dates

              Created:
              Updated: