Strange error adding to Whoosh index

Question

Can anyone help me with this strange error I'm getting when adding a new document to a Whoosh index?

Here's the code:

def add_to_index(self, doc):
    ix = index.open_dir(self.index_dir)
    writer = AsyncWriter(ix) # use async writer to prevent write lock errors
    writer.add_document(**self.get_doc_args(doc))
    writer.commit()

def get_doc_args(self, doc):
    return {
        'id':        u""+str(doc['id']),
        'org':       doc['org__id'],
        'created':   doc['created_date'],
        'date':      doc['received_date'],
        'from_addr': doc['from_addr'],
        'subject':   doc['subject'],
        'body':      doc['messagebody__cleaned_message']
    }

I get the following error:

TypeError('ord() expected a character, but string of length 0 found',)
Traceback (most recent call last):
  File "/usr/local/lib/python2.6/dist-packages/celery/execute/trace.py", line 36, in trace
    return cls(states.SUCCESS, retval=fun(*args, **kwargs))
  File "/usr/local/lib/python2.6/dist-packages/celery/app/task/__init__.py", line 232, in __call__
    return self.run(*args, **kwargs)
  File "/usr/local/lib/python2.6/dist-packages/celery/app/__init__.py", line 172, in run
    return fun(*args, **kwargs)
  File "/mnt/deploy/prod/chorus/src/chorus/../chorus/search/__init__.py", line 131, in index_message
    MessageSearcher().add_to_index(message)
  File "/mnt/deploy/prod/chorus/src/chorus/../chorus/search/__init__.py", line 29, in add_to_index
    writer.commit()
  File "/usr/local/lib/python2.6/dist-packages/whoosh/writing.py", line 423, in commit
    self.writer.commit(*args, **kwargs)
  File "/usr/local/lib/python2.6/dist-packages/whoosh/filedb/filewriting.py", line 501, in commit
    new_segments = mergetype(self, self.segments)
  File "/usr/local/lib/python2.6/dist-packages/whoosh/filedb/filewriting.py", line 78, in MERGE_SMALL
    reader = SegmentReader(writer.storage, writer.schema, seg)
  File "/usr/local/lib/python2.6/dist-packages/whoosh/filedb/filereading.py", line 63, in __init__
    self.termsindex = TermIndexReader(tf)
  File "/usr/local/lib/python2.6/dist-packages/whoosh/filedb/filetables.py", line 590, in __init__
    super(TermIndexReader, self).__init__(dbfile)
  File "/usr/local/lib/python2.6/dist-packages/whoosh/filedb/filetables.py", line 502, in __init__
    OrderedHashReader.__init__(self, dbfile)
  File "/usr/local/lib/python2.6/dist-packages/whoosh/filedb/filetables.py", line 379, in __init__
    HashReader.__init__(self, dbfile)
  File "/usr/local/lib/python2.6/dist-packages/whoosh/filedb/filetables.py", line 187, in __init__
    self.hashtype = dbfile.read_byte()
  File "/usr/local/lib/python2.6/dist-packages/whoosh/filedb/structfile.py", line 219, in read_byte
    return ord(self.file.read(1))

Strangely, the exact same code using a standard writer (i.e. not AsyncWriter) works just fine. What am I missing here? Note that in production I have to use AsyncWriter in order to avoid LockErrors.

Answer 1

Ended up finding a solution; it's called Solr :-)