Hi Olivier,
On Mon, Mar 31, 2025 at 10:01:13AM +0200, Olivier D wrote:
> Hello there !
>
> I developed a lua action for HAProxy (v3.1) that returns a full http
> response without any backend.
> For this I'm using txn:done{}.
> It's working great, with great performances too (+30k/sec queries handled).
> But responses are not compressed, and it seems lua responses are not
> transiting through HAProxy compression module.
> Is it expected behaviour, and if so, How can I compress my responses ? It
> seems zlib lua package is not available in official haproxy images so I
> cannot compress it myself directly in LUA (or maybe I'm missing something,
> I'm not a lua guy).
I don't see a good reason for Lua responses not being compressed. There
are multiple reasons for a response not being compressed, among which
the following (copy-pasted from the doc):
Compression is disabled when:
* the request does not advertise a supported compression algorithm in the
"Accept-Encoding" header
* the response message is not HTTP/1.1 or above
* HTTP status code is not one of 200, 201, 202, or 203
* response contain neither a "Content-Length" header nor a
"Transfer-Encoding" whose last value is "chunked"
* response contains a "Content-Type" header whose first value starts with
"multipart"
* the response contains the "no-transform" value in the "Cache-control"
header
* User-Agent matches "Mozilla/4" unless it is MSIE 6 with XP SP2, or MSIE 7
and later
* The response contains a "Content-Encoding" header, indicating that the
response is already compressed (see compression offload)
* The response contains an invalid "ETag" header or multiple ETag headers
* The payload size is smaller than the minimum size
(see compression minsize-res)
For example have you tried with a content-length header to see if that
changes anything ? Note that I'm not sure what happens in case we want
chunking since the Lua code will obviously not emit chunks by itself.
Regards,
Willy
