September 2020 - Koha-devel - lists.koha-community.org

Add ProxyTimeout to Plack Koha due to mod_cgi bug
by dcook＠prosentient.com.au 07 Sep '20

07 Sep '20

Hi all, Last week, I discovered a bug in Apache httpd's mod_cgi. Basically, it means that mod_cgi does not timeout until 2x the duration of TimeOut, while mod_proxy_http (used by Plack) times out after 1x the duration of TimeOut. You can see the details at https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=26400. The Apache community worked very quickly, and together we've resolved the bug, but I don't think Apache backport fixes. That said, there's been an open bug report in Debian for 5 years (https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=780123) I'll send an email in telling them that this has been fixed upstream. I wouldn't count on a backport though. In any case, the real importance here is that we harmonize people's expectations. With Bug 15218, we started using CGI mode for certain long-running processes. It might be that this isn't 100% necessary in all cases, if we just increase the ProxyTimeout to match the effective TimeOut time of CGI processes. David Cook Software Engineer Prosentient Systems 72/330 Wattle St Ultimo, NSW 2007 Australia Office: 02 9212 0899 Online: 02 8005 0595

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Is Indexdata's Zebra a dead project?
by dcook＠prosentient.com.au 04 Sep '20

04 Sep '20

Hi all, I just noticed that Indexdata doesn't provide Zebra packages past Debian Stretch: http://ftp.indexdata.dk/pub/zebra/debian/. The latest Ubuntu package is for 18.04 (Bionic): http://ftp.indexdata.dk/pub/zebra/ubuntu/ In fact, Zebra hasn't been updated since August 2018 according to the changelog: https://software.indexdata.com/zebra/doc/NEWS. In Debian, it looks like Debian 11 Bullseye will have the latest Zebra (2.1.4), so there is that at least. I guess people using Debian 10 Buster will either need to use the buggy Zebra (2.0.59) in Debian or maybe use the Stretch packages from Indexdata. But then from Bullseye onwards there will be the latest Zebra until Debian drops the package I guess. All the more reason to move more to Elasticsearch? David Cook Software Engineer Prosentient Systems 72/330 Wattle St Ultimo, NSW 2007 Australia Office: 02 9212 0899 Online: 02 8005 0595

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Apache directive TimeOut works differently when using mod_cgi (CGI) vs mod_proxy_http (Plack)
by dcook＠prosentient.com.au 04 Sep '20

04 Sep '20

Hi all, While troubleshooting Apache TimeOut for Plack vs CGI (https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=26128) I discovered that Apache seems to respect TimeOut when measuring a timeout proxying requests to Plack. However, it actually *doubles* the time when running CGI scripts on its own. I've looked through the Apache httpd and apr source code, and it's not obvious to me at a glance why this happens, but I think it's important for us to realize this, because it means the solution presented by "Make processes that rely on background jobs run in CGI mode" https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=15218 might not always be necessary. Based on my investigation, it seems the reason some scripts work in CGI but not in Plack is simply because of the different way timeouts occur. If we just raise the ProxyTimeout to twice the value of TimeOut (ie change it to 600 to be 2*TimeOut), then we'll be getting the same behaviour. Of course, the real solution in these cases is still to use asynchronous processing via "Add a task queue" (https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=22417) In any case, I thought it was important to share my findings, because it means we might actually be able to reduce our dependency on CGI now even before Bug 22417 is pushed. Thank you, David Cook Software Engineer Prosentient Systems 72/330 Wattle St Ultimo, NSW 2007 Australia Office: 02 9212 0899 Online: 02 8005 0595

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Strange Plack-related bug
by dcook＠prosentient.com.au 03 Sep '20

03 Sep '20

Hi all, I was running Koha Plack on OpenSuse (using CPANed libraries), and I noticed that creating a new authority would take me to /cgi-bin/koha/authorities/detail.pl?authid=1, which then spat out an error in my logs of "Subroutine build_tabs redefined at /path/to/koha/intranet/cgi-bin/authorities/detail.pl line 56." After that, it became impossible to create a new authority via /cgi-bin/koha/authorities/authorities.pl. Seemingly because the build_tabs subroutine had been redefined to be incompatible with authorities.tt. I noticed that this only affected my OpenSuse Koha. It didn't affect Debian or Ubuntu. That makes me think that it's due to an issue with the Plack libraries being used. On Ubuntu I was using 1.0047, on Debian I was using 1.0042, and on OpenSuse I was using 1.0039. My guess is that it's an issue with the older library, but I really don't know. Wondering if anyone else has encountered this particular issue. Same Koha code running on each OS, but yeah. the OpenSuse was having issues that the Debian/Ubuntu didn't. David Cook Software Engineer Prosentient Systems 72/330 Wattle St Ultimo, NSW 2007 Australia Office: 02 9212 0899 Online: 02 8005 0595

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Koha Community Newsletter: August 2020
by Koha Newsletter 01 Sep '20

01 Sep '20

The Koha Community Newsletter for August 2020 is here: https://koha-community.org/koha-community-newsletter-august-2020/ Many thanks to the folks who submitted articles and news to this month's newsletter. Please feel free to email me with any corrections or suggestions. -- Chad Roseburg Editor, Koha Community Newsletter

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