Bug 51489

I found out that I have no issue at all if the config consistently uses a slash after the load balancer id.

<Proxy balancer://196f045aca6adc82a0b6eea93ed286a1/>
    BalancerMember http://server-1.local/ status=-SE
    BalancerMember http://server-2.local/ status=-SE
</Proxy>
<VirtualHost 10.8.16.33:80>
    ServerName frontend.local

    <Location />
	ProxyPass balancer://196f045aca6adc82a0b6eea93ed286a1/
	ProxyPassReverse balancer://196f045aca6adc82a0b6eea93ed286a1/
    </Location>
</VirtualHost>

So, please consider the case as solved and the patch as void.

No, consistently using a slash after the load balancer id does *not* help: In this case every backend request gets an additional slash before the path. Maybe we should fix *this* issue then...

Please test

<Proxy balancer://196f045aca6adc82a0b6eea93ed286a1>
    BalancerMember http://server-1.local/ status=-SE
    BalancerMember http://server-2.local/ status=-SE
</Proxy>

Does this then result in doubled-slashes?

yes

Does somebody have a patch for 2.2.22 for this?

The above patch seems to be for an older version and the logic seemed to have changed (I only checked .21 and .22).

I can work on an updated patch (added to my TODO list), but I will need some
time for it due to a lot of other things keeping me busy at the moment...

I just tried to reproduce the issue again with Apache 2.4.2. Now the directive
doesn't work at all in a load balancer setup. :(

This tiny patch for Apache 2.4.2 makes the ProxyPassReverse work again in a load balancer setup, however, the initially reported bug with the additional slash is then still unfixed:

--- a/modules/proxy/proxy_util.c
+++ b/modules/proxy/proxy_util.c
@@ -852,6 +852,7 @@ PROXY_DECLARE(const char *) ap_proxy_location_reverse_map(request_rec *r,
             (balancer = ap_proxy_get_balancer(r->pool, sconf, real, 1))) {
             int n, l3 = 0;
             proxy_worker **worker = (proxy_worker **)balancer->workers->elts;
+            real += strlen(BALANCER_PREFIX);
             const char *urlpart = ap_strchr_c(real, '/');
             if (urlpart) {
                 if (!urlpart[1])

Ok, issue from last comment is already fixed in trunk via PR #45434.

Created attachment 29145 [details]
Fix for Apache 2.4.2 (including fix for PR #45434)

Using gdb I just figured out what went wrong. Attached you can find my patch that made all things work for me using Apache 2.4.2.

I also tried to craft a test case for this issue, but for whatever reason the test harness does not fail (maybe related to the intense usage of non-default ports in the test setup).

Ah, I missed this bug before, sorry.  Yes, this is fixed for the next 2.4.x release, I'll update CHANGES to ref this bug since it's a different bug to the 2.2 issue, and a regression.

I fear you got me wrong. The changeset you committed in SVN rev. 1374264 should be reverted, as the bug that got fixed in branch httpd-2.4.x by SVN rev. 1365604 is PR 45434 only. The issue that I reported in PR 51489 is *not* fixed by changing the CHANGES file only (as in SVN rev. 1374264).

Or did I miss anything?

Oh, I see.  Sorry, no, I missed the point.

Created attachment 29248 [details]
Fix additional slash in load balancer setups

I've just rewritten the patch to catch the problem more precisely.

The patch from previous comment is based on branch httpd-2.4.x, SVN rev. 1374290.

See:

http://svn.apache.org/viewvc?view=revision&revision=1386576
http://svn.apache.org/viewvc?view=revision&revision=1386578