title: Can you append data to an existing Avro data file?
body: <p>It seems like there isn't any way to append data to an existing Avro serialized file.  I'd like to have multiple processes writing to a single avro file, but it looks like each time I open it, I start over from scratch.  I don't want to read in all the data and then write it back out again.</p>
  
  <p>Using the ruby example code I have tried "ab" and "ab+" as various settings, but no joy.</p>
  
  <pre><code>file = File.open('data.avr', 'wb')
  schema = Avro::Schema.parse(SCHEMA)
  writer = Avro::IO::DatumWriter.new(schema)
  dw = Avro::DataFile::Writer.new(file, writer, schema)
  dw &lt;&lt; {"username" =&gt; "john", "age" =&gt; 25, "verified" =&gt; true}
  dw &lt;&lt; {"username" =&gt; "ryan", "age" =&gt; 23, "verified" =&gt; false}
  dw.close
  </code></pre>