[jira] [Commented] (AVRO-959) python implementation calls seek on input, unable to read avros from a stream

["Harsh J (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/AVRO-959?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13649531#comment-13649531 ] 

Harsh J commented on AVRO-959:
------------------------------

It is possible to seek the standard input, iff a file is used as one:

{code}
➜  ~  cat foo.py
import sys

inp = sys.stdin
inp.seek(0)
➜  ~  cat foo.py | python foo.py
Traceback (most recent call last):
  File "foo.py", line 4, in <module>
    inp.seek(0)
IOError: [Errno 29] Illegal seek
➜  ~  python foo.py < foo.py
➜  ~  python foo.py <(cat foo.py) 
➜  ~  
{code}

We could probably document and leverage this?
                
> python implementation calls seek on input, unable to read avros from a stream
> -----------------------------------------------------------------------------
>
>                 Key: AVRO-959
>                 URL: https://issues.apache.org/jira/browse/AVRO-959
>             Project: Avro
>          Issue Type: Bug
>          Components: python
>    Affects Versions: 1.6.1
>            Reporter: Sean Jensen-Grey
>
> The python implementation of Avro calls seek on the input file handle which precludes it from being a stream (stdin, hadoop streaming, etc)
> {code}
> ack -a -i seek
> src/avro/datafile.py
> 109:      # seek to the end of the file and prepare for writing
> 110:      writer.seek(0, 2)
> 190:    DataFileReader.seek(long). Forces the end of the current block,
> 261:    self.reader.seek(0, 2)
> 263:    self.reader.seek(remember_pos)
> 270:    # seek to the beginning of the file to get magic block
> 271:    self.reader.seek(0, 0) 
> 316:    return True. Otherwise, seek back to where we started and return False.
> 320:      self.reader.seek(-SYNC_SIZE, 1)
> src/avro/io.py
> 148:    reader is a Python object on which we can call read, seek, and tell.
> 267:    self.reader.seek(self.reader.tell() + n)
> src/avro/txipc.py
> 217:    request.content.seek(0, 0)
> test/test_io.py
> 137:    writer.seek(0)
> {code}

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