Here is a first patch that adds the compression feature. I have tried it with DefaultCodec, GzipCodec, BZip2Codec and it seems OK.
If it looks good, I'll submit another patch with the current changes in the documentation.
Though everything seems to work, there is something that I don't really understand. I have tcpdumped network traffic and when compression is enabled, I can't see any more the HTTP POST protocol appearing in Wireshark. I just see various TCP segments that hold my Chukwa chunk, but I can't see any higher protocol than TCP. What is more, using the same file (19KB) to compare between compress (size compress: 7.6 KB) and uncompressed tcpdumps, I have noticed that I get more (smaller) TCP segments with compressed communication than with uncompressed communication. Could someone enlightens me?