HttpProxyDiscoveryTaskForce < LCG

---+ WLCG Http Proxy Discovery Task Force

Contents of this page:
%TOC%

---++ Mandate

   * Define the WLCG-wide standards for grid jobs to find out what HTTP proxy or proxies to use

---++ Rationale

   * This problem has already been attempted to be solved in many different ways, none of them very completely, for example by !CernVM, !GlideinWMS, ATLAS site configurator, generator files for ATLAS & CMS, and now the [[https://github.com/hep-gc/shoal][Shoal]] tool for cloud proxies
   * Having a standard would make it much easier for new applications to use local http proxy caches

---++ Members

   * [[https://phonebook.cern.ch/phonebook/?from=xwho#personDetails/?id=541401][Doug Benjamin]] (ATLAS, added March 2015)
   * [[https://phonebook.cern.ch/phonebook/?from=xwho#id=PE375888][Barry Blumenfeld]] (CMS)
   * [[https://phonebook.cern.ch/phonebook/?from=xwho#id=PE667634][Jakob Blomer]] (CERN-PH-SFT)
   * [[https://phonebook.cern.ch/phonebook/?from=xwho#id=PE659869][Brian Bockelman]] (CMS, OSG)
   * [[https://phonebook.cern.ch/phonebook/?from=xwho#id=PE614788][Dan Bradley]] (CMS)
   * [[https://phonebook.cern.ch/phonebook/?from=xwho#id=PE665120][John DeStefano]] (ATLAS, OSG)
   * [[https://phonebook.cern.ch/phonebook/?from=xwho#id=PE654209][Alastair Dewhurst]] (ATLAS)
   * [[https://phonebook.cern.ch/phonebook/?from=xwho#id=PE662978][Dave Dykstra]] (CMS, OSG), Chair
   * [[https://phonebook.cern.ch/phonebook/?from=xwho#id=PE610863][Ian Gable]] (ATLAS)
   * [[https://phonebook.cern.ch/phonebook/#personDetails/?id=650724][Costin Grigoras]] (ALICE, added July 2014)
   * [[https://phonebook.cern.ch/phonebook/?from=xwho#id=PE653174][John Hover]] (ATLAS, OSG)
   * [[https://phonebook.cern.ch/phonebook/?from=xwho#id=PE576600][Stefan Roiser]] (LHCb)

All members can be contacted at wlcg-ops-coord-tf-httpproxydiscovery@cern.ch

---++ Task Overview
| *Task* | *Deadline* | *Progress* | *Affected VO* | *Affected Siites* | *Comment* | 
| Implement squid monitoring based on GOCDB/OIM | November 2014 | 100% | All | All | Done by Alastair Dewhurst |
| Get critical mass of sites registered in GOCDB/OIM | February 2015 | 100% | All | All | Done |
| Implement WPAD service wlcg-wpad.cern.ch/wpad.dat | September 2016 | 100% | All | All | Done by Dave Dykstra. |
| Update CVMFS client to robustly support round-robin proxies | December 2014 | 100% | All | All | Tracked in [[https://sft.its.cern.ch/jira/browse/CVM-457][JIRA ticket]] Implemented for cvmfs 2.1.20 |

---++ Meetings
   * [[HttpProxyDiscoveryMeetingNotes20130424][Notes from 24 April 2013 meeting]]

---++ Presentations
   * [[https://indico.cern.ch/event/505613/contributions/2230709/attachments/1346624/2030637/Oral-180.pdf][CHEP 2016 presentation describing the live WLCG WPAD service]] and [[https://iopscience.iop.org/article/10.1088/1742-6596/898/5/052043][published paper]]
   * [[https://indico.cern.ch/event/773049/contributions/3473822/attachments/1935937/3211455/CHEP19_Talk_WPAD.pdf][CHEP 2019 presentation describing shoal integration into WLCG WPAD]] and [[https://home.fnal.gov/~dwd/CHEP19_Paper_WPAD.pdf][paper draft]]

---++ References

   * This topic was discussed some in the SquidMonitoringTaskForce before it was determined to make a separate task force, particularly in this [[SquidMonitoringTFInfoSystem][configuration information system proposal]] and this [[https://indico.cern.ch/getFile.py/access?subContId=1&contribId=0&resId=0&materialId=slides&confId=231008][WLCG operations coordination meeting presentation]].
   * [[http://en.wikipedia.org/wiki/Web_Proxy_Autodiscovery_Protocol][Web Proxy Auto Discovery protocol]]
   * [[http://en.wikipedia.org/wiki/Proxy_auto-config][Proxy Auto-Config file format]]
   * [[http://github.com/pacparser/pacparser][pacparser library]]
   * [[http://github.com/pacwget/pacwget][pacwget tool]]
   * [[https://twiki.cern.ch/twiki/bin/view/Frontier/ClientRetryStrategy][Frontier client retry strategy]]

---++ Proposal

   * [[HttpProxyDiscoveryProposal][Proposed standards for http proxy discovery]]

---++ Agreement

The task force agreed to the standards in HttpProxyDiscoveryProposal, and the http://wlcg-wpad.cern.ch/wpad.dat service is now in operation.   Strong negative feedback was received from the first site that attempted to implement http://wpad/wpad.dat (that is, CERN) so the task force agreed that clients would first try an additional URL http://grid-wpad/wpad.dat.  In addition, a http://wlcg-wpad.fnal.gov/wpad.dat service has been made available as an identical partner to the one in cern.ch.

In summary, WLCG clients SHOULD attempt to read Proxy Auto Config files from the following URLs:
<pre>
http://grid-wpad/wpad.dat; http://wpad/wpad.dat; http://wlcg-wpad.cern.ch/wpad.dat; http://wlcg-wpad.fnal.gov/wpad.dat
</pre>
In general they SHOULD be tried in that order, although clients MAY choose to reverse the order of the last two.
This topic: LCG > WebHome > WLCGCommonComputingReadinessChallenges > WLCGOperationsWeb > WLCGOpsCoordination > HttpProxyDiscoveryTaskForce
Topic revision: r27 - 2020-03-18 - DaveDykstra
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