text_combined: alex martelli typcyyjgmailcom tue apr 29 2008 510 nick coghlan wrote perhaps schedmutex could dumped demo directory perhaps get rid entirely see anyone real use case complains like modules particularly hard dig svn decide want keep real use cases im already complaining id rather get specific details last 3 years ive working google area call cluster management imagine recent important use cases may systems play important roles innards google clusters exactly stuff google likes chat somewhat abstractly suppose part keeping clusters healthy certain generation n cluster management infrastructure periodically running eg via cron several scripts perform housekeeping sysadm tasks check vital services running healthy allocating replacement machines ensure redundancy remains good vital server keeled replaced hot spare ensuring multiplyredundant backups important data offsite like next generation n1 rewrite morass scripts originally mix bash perl python python far good notice using cron far optimal tasks performed different periodicity take different times sometimes end overlapping thats good sequenced introduce locking processes still leaves times several python processes alive one waiting lock uselessly consuming machine resources machines arent limited liverunning servers resources taken overhead sysadm tasks must minimized big breakthrough rewrite whole thing one python daemon based sched locking delicate bugs race conditions disappear steady predictable resourceconsumption footprint still want avoid conditions longrunning sysadm daemon grows memory footprint never shrinks rare tasks risk fork work subprocess parent waits etc suddenly wonderfully new higher level testability level tests living unittests full systemintegration tests use simulated accelerated timeline sched mock parts get information outside perform actions exercise whole system logic workflow almost well full systemintegration test orders magnitude faster without requiring whole cluster devoted test sure sched taken away could take back make part specific system rather using standard library argument would apply vast majority library modules particularly purepython ones think hope springcleaning cruft drastically rethinking whole idea batteries included right besides google know many shops using python cluster management system administration tasks example rackspace sponsor pycon busy trying hire pythonistas cluster management infrastructure software also appears allpython large shops like rackspace google least affected make sched part code though would needlessly add one epsilon inevitable resistance 2 3 migration course encounter particularly among conservative reliabilityisall types sysadms lot sysadm work happens far smaller environments often parttime admins finding sched existed perfect replacing cron many jobs removed still downloaded xyz would significant chore tasks unrelated system administration consider example instructive httpaspnactivestatecomaspncookbookpythonrecipe413137 original home cooked solution without sched really pretty bad unreliable raymond hettinger came saved day showing trivially use sched right solid lightweight reliable threads locks things could ask needed discuss pure simulation opposed simulationtesting systems designed normally use real sched already seems plenty use cases justify retaining sched library alex _______________________________________________ python3000 mailing list smsbmo9552pythonorg httpmailpythonorgmailmanlistinfopython3000 unsubscribe httpmailpythonorgmailmanoptionspython3000python300040tangomucom thu 07 aug 2008 204814 0700 python3000 pep 3108 stdlib reorgcleanup