<VirtualHost *:80>
    DocumentRoot /srv/emptywebroot
    <Directory /srv/emptywebroot>
        Require all denied
    </Directory>

    # Dashboard proxy
    RewriteEngine on
    LogLevel alert rewrite:trace6
    RewriteCond %{HTTP:Upgrade} =websocket
    RewriteRule /dashboard/(.*) ws://dashboard:3838/dashboard/$1 [P,L]
    RewriteCond %{HTTP:Upgrade} !=websocket
    RewriteRule /dashboard/(.*) http://dashboard:3838/dashboard/$1 [P,L]
    ProxyPreserveHost on
    ProxyPassReverse /dashboard http://dashboard:3838/dashboard
</VirtualHost>

[Wed Mar 21 14:04:08.051070 2018] [rewrite:trace2] [pid 1548:tid 140453800191744] mod_rewrite.c(476): [client 10.174.120.65:59506] 10.174.120.65 - - [idisrv.sivsa.com/sid#7fbdfdd1ed20][rid#7fbdf018f0a0/initial] init rewrite engine with requested uri /dashboard/
[Wed Mar 21 14:04:08.051114 2018] [rewrite:trace1] [pid 1548:tid 140453800191744] mod_rewrite.c(476): [client 10.174.120.65:59506] 10.174.120.65 - - [idisrv.sivsa.com/sid#7fbdfdd1ed20][rid#7fbdf018f0a0/initial] pass through /dashboard/
[Wed Mar 21 14:04:08.051176 2018] [rewrite:trace3] [pid 1548:tid 140453800191744] mod_rewrite.c(476): [client 10.174.120.65:59506] 10.174.120.65 - - [idisrv.sivsa.com/sid#7fbdfdd1ed20][rid#7fbdf018f0a0/initial] [perdir /dashboard/] add path info postfix: /srv/emptywebroot/dashboard -> /srv/emptywebroot/dashboard/
[Wed Mar 21 14:04:08.051186 2018] [rewrite:trace3] [pid 1548:tid 140453800191744] mod_rewrite.c(476): [client 10.174.120.65:59506] 10.174.120.65 - - [idisrv.sivsa.com/sid#7fbdfdd1ed20][rid#7fbdf018f0a0/initial] [perdir /dashboard/] applying pattern '(.*)' to uri '/srv/emptywebroot/dashboard/'
[Wed Mar 21 14:04:08.051199 2018] [rewrite:trace4] [pid 1548:tid 140453800191744] mod_rewrite.c(476): [client 10.174.120.65:59506] 10.174.120.65 - - [idisrv.sivsa.com/sid#7fbdfdd1ed20][rid#7fbdf018f0a0/initial] [perdir /dashboard/] RewriteCond: input='' pattern='=websocket' => not-matched
[Wed Mar 21 14:04:08.051208 2018] [rewrite:trace3] [pid 1548:tid 140453800191744] mod_rewrite.c(476): [client 10.174.120.65:59506] 10.174.120.65 - - [idisrv.sivsa.com/sid#7fbdfdd1ed20][rid#7fbdf018f0a0/initial] [perdir /dashboard/] add path info postfix: /srv/emptywebroot/dashboard -> /srv/emptywebroot/dashboard/
[Wed Mar 21 14:04:08.051216 2018] [rewrite:trace3] [pid 1548:tid 140453800191744] mod_rewrite.c(476): [client 10.174.120.65:59506] 10.174.120.65 - - [idisrv.sivsa.com/sid#7fbdfdd1ed20][rid#7fbdf018f0a0/initial] [perdir /dashboard/] applying pattern '(.*)' to uri '/srv/emptywebroot/dashboard/'
[Wed Mar 21 14:04:08.051225 2018] [rewrite:trace4] [pid 1548:tid 140453800191744] mod_rewrite.c(476): [client 10.174.120.65:59506] 10.174.120.65 - - [idisrv.sivsa.com/sid#7fbdfdd1ed20][rid#7fbdf018f0a0/initial] [perdir /dashboard/] RewriteCond: input='' pattern='!=websocket' => matched
[Wed Mar 21 14:04:08.051234 2018] [rewrite:trace2] [pid 1548:tid 140453800191744] mod_rewrite.c(476): [client 10.174.120.65:59506] 10.174.120.65 - - [idisrv.sivsa.com/sid#7fbdfdd1ed20][rid#7fbdf018f0a0/initial] [perdir /dashboard/] rewrite '/srv/emptywebroot/dashboard/' -> 'http://dashboard:3838//srv/emptywebroot/dashboard/'
[Wed Mar 21 14:04:08.051243 2018] [rewrite:trace2] [pid 1548:tid 140453800191744] mod_rewrite.c(476): [client 10.174.120.65:59506] 10.174.120.65 - - [idisrv.sivsa.com/sid#7fbdfdd1ed20][rid#7fbdf018f0a0/initial] [perdir /dashboard/] escaped URI in per-dir context for proxy, http://dashboard:3838//srv/emptywebroot/dashboard/ -> http://dashboard:3838//srv/emptywebroot/dashboard/
[Wed Mar 21 14:04:08.051264 2018] [rewrite:trace2] [pid 1548:tid 140453800191744] mod_rewrite.c(476): [client 10.174.120.65:59506] 10.174.120.65 - - [idisrv.sivsa.com/sid#7fbdfdd1ed20][rid#7fbdf018f0a0/initial] [perdir /dashboard/] forcing proxy-throughput with http://dashboard:3838//srv/emptywebroot/dashboard/
[Wed Mar 21 14:04:08.051272 2018] [rewrite:trace1] [pid 1548:tid 140453800191744] mod_rewrite.c(476): [client 10.174.120.65:59506] 10.174.120.65 - - [idisrv.sivsa.com/sid#7fbdfdd1ed20][rid#7fbdf018f0a0/initial] [perdir /dashboard/] go-ahead with proxy request proxy:http://dashboard:3838//srv/emptywebroot/dashboard/ [OK]