Some regtests involve multiple requests from multiple clients, which can
be dispatched as multiple requests to a server. It turns out that the
idle connection sharing works so well that very quickly few connections
are used, and regularly some of the remaining idle server connections
time out at the moment they were going to be reused, causing those random
"HTTP header incomplete" traces in the logs that make them fail often. In
the end this is only an artefact of the test environment.
And indeed, some tests like normalize-uri which perform a lot of reuse
fail very often, about 20-30% of the times in the CI, and 100% of the
time in local when running 1000 tests in a row. Others like ubase64,
sample_fetches or vary_* fail less often but still a lot in tests.
This patch addresses this by adding "tune.idle-pool.shared off" to all
tests which have at least twice as many requests as clients. It proves
very effective as no single error happens on normalize-uri anymore after
10000 tests. Also 100 full runs of all tests yield no error anymore.
One test is tricky, http_abortonclose, it used to fail ~10 times per
1000 runs and with this workaround still fails once every 1000 runs.
But the test is complex and there's a warning in it mentioning a
possible issue when run in parallel due to a port reuse.
Make HAProxy set the `Vary: Accept-Encoding` response header if it compressed
the server response.
Technically the `Vary` header SHOULD also be set for responses that would
normally be compressed based off the current configuration, but are not due
to a missing or invalid `Accept-Encoding` request header or due to the
maximum compression rate being exceeded.
Not setting the header in these cases does no real harm, though: An
uncompressed response might be returned by a Cache, even if a compressed
one could be retrieved from HAProxy. This increases the traffic to the end
user if the cache is unable to compress itself, but it saves another
roundtrip to HAProxy.
see the discussion on the mailing list: https://www.mail-archive.com/haproxy@formilux.org/msg34221.html
Message-ID: 20190617121708.GA2964@1wt.eu
A small issue remains: The User-Agent is not added to the `Vary` header,
despite being relevant to the response. Adding the User-Agent header would
make responses effectively uncacheable and it's unlikely to see a Mozilla/4
in the wild in 2019.
Add a reg-test to ensure the behaviour as described in this commit message.
see issue #121
Should be backported to all branches with compression (i.e. 1.6+).
