Re: java.lang.IllegalArgumentException: Could not load codec 'Lucene62'. Did you forget to add lucene-backward-codecs.jar?

[Andi Vajda]

In rev 1860637 I refreshed the list of supported lucene module to be built
with PyLucene. The lucene-backward-codecs module was indeed missing.

Please, try it out with pylucene 7.7.1 (refresing its Makefile from trunk)
and let me know if it fixes your problem.

Thanks !

Andi..

On Tue, 4 Jun 2019, David Allouche wrote:

Hello,

I use pylucene, and I am upgrading from 6.5.0 to 7.7.1.

Opening my old index using the new pylucene, I get

Traceback (most recent call last):
  ...
  File "/home/user/jobaffinity/lib/luceneindex.py", line 58, in 
create_lucene_index_maybe
    writer = IndexWriter(directory, config)
lucene.JavaError: <super: <class 'JavaError'>, <JavaError object>>
    Java stacktrace:
java.lang.IllegalArgumentException: Could not load codec 'Lucene62'.  Did you 
forget to add lucene-backward-codecs.jar?
    at org.apache.lucene.index.SegmentInfos.readCodec(SegmentInfos.java:428)
    at org.apache.lucene.index.SegmentInfos.readCommit(SegmentInfos.java:360)
    at org.apache.lucene.index.SegmentInfos.readCommit(SegmentInfos.java:291)
    at org.apache.lucene.index.IndexWriter.<init>(IndexWriter.java:845)
Caused by: java.lang.IllegalArgumentException: An SPI class of type 
org.apache.lucene.codecs.Codec with name 'Lucene62' does not exist.  You need 
to add the corresponding JAR file supporting this SPI to your classpath.  The 
current classpath supports the following names: [Lucene70]
    at org.apache.lucene.util.NamedSPILoader.lookup(NamedSPILoader.java:116)
    at org.apache.lucene.codecs.Codec.forName(Codec.java:116)
    at org.apache.lucene.index.SegmentInfos.readCodec(SegmentInfos.java:424)
    ... 3 more

I am really not familiar with the Java side of things. With some help from the 
web, I found out where to download the jars.

I presume I need 
http://central.maven.org/maven2/org/apache/lucene/lucene-backward-codecs/7.7.1/lucene-backward-codecs-7.7.1.jar

But then, I am quite clueless about what to do. I tried dumping the jar right 
next to lucene-core-7.7.1.jar, in my 
$(VENV)/lib/python2.7/site-packages/lucene, but that does not seem to help.

I have a large-ish index with about 22M entries, used in a public-facing 
service, so I very much like to avoid rebuilding the index every time I upgrade 
pylucene.

I could reverse-engineer this script:
https://github.com/cominvent/solr-tools/blob/master/upgradeindex/upgradeindex.sh

But that would require me to put the service down while running the migration.

How can I package the lucene-backwards-codecs in pylucene?