Bug 65429 - order of ProxyPass and ProxyPassMatch seems to matter
Summary: order of ProxyPass and ProxyPassMatch seems to matter
Status: RESOLVED FIXED
Alias: None
Product: Apache httpd-2
Classification: Unclassified
Component: mod_proxy (show other bugs)
Version: 2.4.48
Hardware: PC Linux
: P2 normal (vote)
Target Milestone: ---
Assignee: Apache HTTPD Bugs Mailing List
URL:
Keywords: FixedInTrunk
Depends on:
Blocks:
 
Reported: 2021-07-03 11:14 UTC by Tobias Wendorff
Modified: 2021-09-20 23:04 UTC (History)
0 users


Attachments
Don't confuse/merge matchable and non-matchable proxy workers at loading (6.67 KB, patch)
2021-07-03 13:56 UTC, Yann Ylavic 		Details | Diff
ProxyPassMatch full patch (14.79 KB, patch)
2021-07-03 14:39 UTC, Yann Ylavic 		Details | Diff
View All Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description Tobias Wendorff 2021-07-03 11:14:43 UTC 
# summary
After upgrading from apache2 v2.4.46 to v2.4.48, the order of ProxyPass and ProxyPatchMatch seems to matter.

# test requests
1. GET http://demo.tobwen.local/internal/
2. GET http://demo.tobwen.local/tiles/osm/19/272348/174392.png

# config (1)
<VirtualHost *:80>
    ServerName demo.tobwen.local
    DocumentRoot /var/www/html/

    ProxyPass "/internal" "http://localhost:8081"    
    ProxyPassMatch "^/tiles/([^/\.]+)/(\d+/\d+/\d+.png)$"   "http://localhost:8081/wmts/$1/webmercator/$2"
</VirtualHost>

# results (1)
On v2.4.46 (and earlier), both test requests worked as expected.
On v2.4.48, the second request suddenly throws an ERROR 404.

# observation
Let's change the order of ProxyPass and ProxyPassMatch.

# config (2)
<VirtualHost *:80>
    ServerName demo.tobwen.local
    DocumentRoot /var/www/html/

    ProxyPassMatch "^/tiles/([^/\.]+)/(\d+/\d+/\d+.png)$"   "http://localhost:8081/wmts/$1/webmercator/$2"
    ProxyPass "/internal" "http://localhost:8081"    
</VirtualHost>

# results (2)
Crazy, now the requests work without a problem.

# conclusion
This seems to be a regression since it worked in earlier versions.
Comment 1 Yann Ylavic 2021-07-03 13:56:41 UTC 
Created attachment 37938 [details]
Don't confuse/merge matchable and non-matchable proxy workers at loading

Could you please try this patch?

The issue is a change in 2.4.48 (r1880772) to allow for parameters (enablereuse, ttl..) in <ProxyMatch>/ProxyPassMatch workers with '$n' substitution in the URL, like <Proxy>/ProxyPass workers.

This patch should fix the regression that makes matchable and non-matchable workers be confused/merged at loading, which is why when the worker http://localhost:8081 (non-matchable) is defined first it blinds the second worker http://localhost:8081/wmts/$1/webmercator/$2 (matchable), thus no worker exists to handle "/tiles/osm/19/272348/174392.png" which ends up being not found in the DocumentRoot.

Note that there is another issue reported in bug 65419 about this change, another patch is available there for a full fix (the two patches can be applied with no conflict).
Comment 2 Tobias Wendorff 2021-07-03 14:30:50 UTC 
I've just tested your patch and it works. Thanks.

Is there a repository where all those patches are collected?
Comment 3 Yann Ylavic 2021-07-03 14:39:45 UTC 
Created attachment 37939 [details]
ProxyPassMatch full patch

Patch for both bug 65419 and bug 65429.

No repository for this full patch so far, I will make a backport proposal with it ASAP.
Comment 4 Yann Ylavic 2021-07-22 18:46:44 UTC 
This patch is proposed for backport to 2.4.x: http://people.apache.org/~ylavic/patches/2.4.x-bz_65419+65429.patch
Comment 6 Yann Ylavic 2021-09-20 23:04:43 UTC 
Fixed in 2.4.49 (r1892569).