What’s new in Celery 4.2 (windowlicker)

Omer Katz (omer.drow at gmail.com)

Change history

What’s new documents describe the changes in major versions, we also have a Change history that lists the changes in bugfix releases (0.0.x), while older series are archived under the History section.

Celery is a simple, flexible, and reliable distributed system to process vast amounts of messages, while providing operations with the tools required to maintain such a system.

It’s a task queue with focus on real-time processing, while also supporting task scheduling.

Celery has a large and diverse community of users and contributors, you should come join us on IRC or our mailing-list.

To read more about Celery you should go read the introduction.

While this version is backward compatible with previous versions it’s important that you read the following section.

This version is officially supported on CPython 2.7, 3.4, 3.5 & 3.6 and is also supported on PyPy.

Table of Contents

Make sure you read the important notes before upgrading to this version.


The 4.2.0 release continues to improve our efforts to provide you with the best task execution platform for Python.

This release is mainly a bug fix release, ironing out some issues and regressions found in Celery 4.0.0.

Traditionally, releases were named after Autechre’s track names. This release continues this tradition in a slightly different way. Each major version of Celery will use a different artist’s track names as codenames.

From now on, the 4.x series will be codenamed after Aphex Twin’s track names. This release is codenamed after his very famous track, Windowlicker.

Thank you for your support!

— Omer Katz

Wall of Contributors

Aaron Harnly <[email protected]> Aaron Harnly <[email protected]> Aaron McMillin <[email protected]> Aaron Ross <[email protected]> Aaron Ross <[email protected]> Aaron Schumacher <[email protected]> abecciu <[email protected]> abhinav nilaratna <[email protected]> Acey9 <[email protected]> Acey <[email protected]> aclowes <[email protected]> Adam Chainz <[email protected]> Adam DePue <[email protected]> Adam Endicott <[email protected]> Adam Renberg <[email protected]> Adam Venturella <[email protected]> Adaptification <[email protected]> Adrian <[email protected]> adriano petrich <[email protected]> Adrian Rego <[email protected]> Adrien Guinet <[email protected]> Agris Ameriks <[email protected]> Ahmet Demir <[email protected]> air-upc <[email protected]> Aitor Gómez-Goiri <[email protected]> Akira Matsuzaki <[email protected]> Akshar Raaj <[email protected]> Alain Masiero <[email protected]> Alan Hamlett <[email protected]> Alan Hamlett <[email protected]> Alan Justino <[email protected]> Alan Justino da Silva <[email protected]> Albert Wang <[email protected]> Alcides Viamontes Esquivel <[email protected]> Alec Clowes <[email protected]> Alejandro Pernin <[email protected]> Alejandro Varas <[email protected]> Aleksandr Kuznetsov <[email protected]> Ales Zoulek <[email protected]> Alexander <[email protected]> Alexander A. Sosnovskiy <[email protected]> Alexander Koshelev <[email protected]> Alexander Koval <[email protected]> Alexander Oblovatniy <[email protected]> Alexander Oblovatniy <[email protected]> Alexander Ovechkin <[email protected]> Alexander Smirnov <[email protected]> Alexandru Chirila <[email protected]> Alexey Kotlyarov <[email protected]> Alexey Zatelepin <[email protected]> Alex Garel <[email protected]> Alex Hill <[email protected]> Alex Kiriukha <[email protected]> Alex Koshelev <[email protected]> Alex Rattray <[email protected]> Alex Williams <[email protected]> Alex Zaitsev <[email protected]> Ali Bozorgkhan <alibozo[email protected]> Allan Caffee <[email protected]> Allard Hoeve <[email protected]> allenling <[email protected]> Alli <[email protected]> Alman One <[email protected]> Alman One <[email protected]> alman-one <[email protected]> Amir Rustamzadeh <[email protected]> [email protected] <[email protected]> Anarchist666 <[email protected]> Anders Pearson <[email protected]> Andrea Rabbaglietti <[email protected]> Andreas Pelme <[email protected]> Andreas Savvides <[email protected]> Andrei Fokau <[email protected]> Andrew de Quincey <[email protected]> Andrew Kittredge <[email protected]> Andrew McFague <[email protected]> Andrew Stewart <[email protected]> Andrew Watts <[email protected]> Andrew Wong <[email protected]> Andrey Voronov <[email protected]> Andriy Yurchuk <[email protected]> Aneil Mallavarapu <[email protected]> anentropic <[email protected]> anh <[email protected]> Ankur Dedania <[email protected]> Anthony Lukach <[email protected]> antlegrand <[email protected]> Antoine Legrand <[email protected]> Anton <[email protected]> Anton Gladkov <[email protected]> Antonin Delpeuch <[email protected]> Arcadiy Ivanov <[email protected]> areski <[email protected]> Armenak Baburyan <[email protected]> Armin Ronacher <[email protected]> armo <[email protected]> Arnaud Rocher <[email protected]> arpanshah29 <[email protected]> Arsenio Santos <[email protected]> Arthur Vigil <[email protected]> Arthur Vuillard <[email protected]> Ashish Dubey <[email protected]> Asif Saifuddin Auvi <[email protected]> Asif Saifuddin Auvi <[email protected]> ask <[email protected]> Ask Solem <[email protected]> Ask Solem <[email protected]> Ask Solem Hoel <[email protected]> aydin <[email protected]> baeuml <[email protected]> Balachandran C <[email protected]> Balthazar Rouberol <[email protected]> Balthazar Rouberol <[email protected]> bartloop <[email protected]> Bartosz Ptaszynski <> Batiste Bieler <[email protected]> bee-keeper <[email protected]> Bence Tamas <[email protected]> Ben Firshman <[email protected]> Ben Welsh <[email protected]> Berker Peksag <[email protected]> Bert Vanderbauwhede <[email protected]> Bert Vanderbauwhede <[email protected]> BLAGA Razvan-Paul <[email protected]> bobbybeever <[email protected]> bobby <[email protected]> Bobby Powers <[email protected]> Bohdan Rybak <[email protected]> Brad Jasper <[email protected]> Branko Čibej <[email protected]> BR <[email protected]> Brendan MacDonell <[email protected]> Brendon Crawford <[email protected]> Brent Watson <[email protected]> Brian Bouterse <[email protected]> Brian Dixon <[email protected]> Brian Luan <[email protected]> Brian May <[email protected]> Brian Peiris <[email protected]> Brian Rosner <[email protected]> Brodie Rao <[email protected]> Bruno Alla <[email protected]> Bryan Berg <[email protected]> Bryan Berg <[email protected]> Bryan Bishop <[email protected]> Bryan Helmig <[email protected]> Bryce Groff <[email protected]> Caleb Mingle <[email protected]> Carlos Garcia-Dubus <[email protected]> Catalin Iacob <[email protected]> Charles McLaughlin <[email protected]> Chase Seibert <[email protected]> ChillarAnand <[email protected]> Chris Adams <[email protected]> Chris Angove <[email protected]> Chris Chamberlin <[email protected]> chrisclark <[email protected]> Chris Harris <[email protected]> Chris Kuehl <[email protected]> Chris Martin <[email protected]> Chris Mitchell <[email protected]> Chris Rose <[email protected]> Chris St. Pierre <[email protected]> Chris Streeter <[email protected]> Christian <[email protected]> Christoph Burgmer <[email protected]> Christopher Hoskin <[email protected]> Christopher Lee <[email protected]> Christopher Peplin <[email protected]> Christopher Peplin <[email protected]> Christoph Krybus <[email protected]> clayg <[email protected]> Clay Gerrard <[email protected].(none)> Clemens Wolff <[email protected]> cmclaughlin <[email protected]> Codeb Fan <[email protected]> Colin McIntosh <[email protected]> Conrad Kramer <[email protected]> Corey Farwell <[email protected]> Craig Younkins <[email protected]> csfeathers <[email protected]> Cullen Rhodes <[email protected]> daftshady <[email protected]> Dan <[email protected]> Dan Hackner <[email protected]> Daniel Devine <[email protected]> Daniele Procida <[email protected]> Daniel Hahler <[email protected]> Daniel Hepper <[email protected]> Daniel Huang <[email protected]> Daniel Lundin <[email protected]> Daniel Lundin <[email protected]> Daniel Watkins <[email protected]> Danilo Bargen <[email protected]> Dan McGee <[email protected]> Dan McGee <[email protected]> Dan Wilson <[email protected]> Daodao <[email protected]> Dave Smith <[email protected]> Dave Smith <[email protected]> David Arthur <[email protected]> David Arthur <[email protected]> David Baumgold <[email protected]> David Cramer <[email protected]> David Davis <[email protected]> David Harrigan <[email protected]> David Harrigan <[email protected]> David Markey <[email protected]> David Miller <[email protected]> David Miller <[email protected]> David Pravec <[email protected]> David Pravec <[email protected]> David Strauss <[email protected]> David White <[email protected]> DDevine <[email protected]> Denis Podlesniy <[email protected]> Denis Shirokov <[email protected]> Dennis Brakhane <[email protected]> Derek Harland <[email protected]> derek_kim <[email protected]> dessant <[email protected]> Dieter Adriaenssens <[email protected]> Dima Kurguzov <[email protected]> dimka665 <[email protected]> dimlev <[email protected]> dmarkey <[email protected]> Dmitry Malinovsky <[email protected]> Dmitry Malinovsky <[email protected]> dmollerm <[email protected]> Dmytro Petruk <[email protected]> dolugen <[email protected]> dongweiming <[email protected]> dongweiming <[email protected]> Dongweiming <ciic[email protected]> dtheodor <[email protected]> Dudás Ádám <[email protected]> Dustin J. Mitchell <[email protected]> D. Yu <[email protected]> Ed Morley <[email protected]> Eduardo Ramírez <[email protected]> Edward Betts <[email protected]> Emil Stanchev <[email protected]> Eran Rundstein <[email protected].(none)> ergo <[email protected]> Eric Poelke <[email protected]> Eric Zarowny <[email protected]> ernop <[email protected]> Evgeniy <[email protected]> evildmp <[email protected]> fatihsucu <[email protected]> Fatih Sucu <[email protected]> Feanil Patel <[email protected]> Felipe <[email protected]> Felipe Godói Rosário <[email protected]> Felix Berger <[email protected]> Fengyuan Chen <[email protected]> Fernando Rocha <[email protected]> ffeast <[email protected]> Flavio Percoco Premoli <[email protected]> Florian Apolloner <[email protected]> Florian Apolloner <[email protected].(none)> Florian Demmer <[email protected]> flyingfoxlee <[email protected]> Francois Visconte <[email protected]> François Voron <[email protected]> Frédéric Junod <[email protected]> fredj <[email protected]> frol <[email protected]> Gabriel <[email protected]> Gao Jiangmiao <[email protected]> GDR! <[email protected]> GDvalle <[email protected]> Geoffrey Bauduin <[email protected]> georgepsarakis <[email protected]> George Psarakis <[email protected]> George Sibble <[email protected]> George Tantiras <[email protected]> Georgy Cheshkov <[email protected]> Gerald Manipon <[email protected]> German M. Bravo <[email protected]> Gert Van Gool <[email protected]> Gilles Dartiguelongue <[email protected]> Gino Ledesma <[email protected]> gmanipon <[email protected]> Grant Thomas <[email protected]> Greg Haskins <[email protected]> gregoire <[email protected]> Greg Taylor <[email protected]> Greg Wilbur <[email protected]> Guillaume Gauvrit <[email protected]> Guillaume Gendre <[email protected]> Gun.io Whitespace Robot <[email protected]> Gunnlaugur Thor Briem <[email protected]> harm <[email protected]> Harm Verhagen <[email protected]> Harry Moreno <[email protected]> hclihn <[email protected]> hekevintran <[email protected]> honux <[email protected]> Honza Kral <[email protected]> Honza Král <[email protected]> Hooksie <[email protected]> Hsiaoming Yang <[email protected]> Huang Huang <[email protected]> Hynek Schlawack <[email protected]> Hynek Schlawack <[email protected]> Ian Dees <[email protected]> Ian McCracken <[email protected]> Ian Wilson <[email protected]> Idan Kamara <[email protected]> Ignas Mikalajūnas <[email protected]> Igor Kasianov <[email protected]> illes <[email protected]> Ilya <[email protected]> Ilya Georgievsky <[email protected]> Ionel Cristian Mărieș <[email protected]> Ionel Maries Cristian <[email protected]> Ionut Turturica <[email protected]> Iurii Kriachko <[email protected]> Ivan Metzlar <[email protected]> Ivan Virabyan <[email protected]> j0hnsmith <[email protected]> Jackie Leng <[email protected]> J Alan Brogan <[email protected]> Jameel Al-Aziz <[email protected]> James M. Allen <[email protected]> James Michael DuPont <[email protected]> James Pulec <[email protected]> James Remeika <[email protected]> Jamie Alessio <[email protected]> Jannis Leidel <[email protected]> Jared Biel <[email protected]> Jason Baker <[email protected]> Jason Baker <[email protected]> Jason Veatch <[email protected]> Jasper Bryant-Greene <[email protected]> Javier Domingo Cansino <[email protected]> Javier Martin Montull <[email protected]> Jay Farrimond <[email protected]> Jay McGrath <[email protected]> jbiel <[email protected]> jbochi <[email protected]> Jed Smith <[email protected]> Jeff Balogh <[email protected]> Jeff Balogh <[email protected]> Jeff Terrace <[email protected]> Jeff Widman <[email protected]> Jelle Verstraaten <[email protected]> Jeremy Cline <[email protected]> Jeremy Zafran <[email protected]> jerry <[email protected]> Jerzy Kozera <[email protected]> Jerzy Kozera <[email protected]> jespern <[email protected]> Jesper Noehr <[email protected]> Jesse <[email protected]> jess <[email protected]> Jess Johnson <[email protected]> Jian Yu <[email protected]> JJ <[email protected]> João Ricardo <[email protected]> Jocelyn Delalande <[email protected]> JocelynDelalande <[email protected]> Joe Jevnik <[email protected]> Joe Sanford <[email protected]> Joe Sanford <[email protected]> Joey Wilhelm <[email protected]> John Anderson <[email protected]> John Arnold <[email protected]> John Barham <[email protected]> John Watson <[email protected]> John Watson <[email protected]> John Watson <[email protected]> John Whitlock <[email protected]> Jonas Haag <[email protected]> Jonas Obrist <[email protected]> Jonatan Heyman <[email protected]> Jonathan Jordan <[email protected]> Jonathan Sundqvist <[email protected]> jonathan vanasco <[email protected]> Jon Chen <[email protected]> Jon Dufresne <[email protected]> Josh <[email protected]> Josh Kupershmidt <[email protected]> Joshua “jag” Ginsberg <[email protected]> Josue Balandrano Coronel <[email protected]> Jozef <[email protected]> jpellerin <[email protected].(none)> jpellerin <[email protected]> JP <[email protected]> JTill <[email protected]> Juan Gutierrez <[email protected]> Juan Ignacio Catalano <[email protected]> Juan Rossi <[email protected]> Juarez Bochi <[email protected]> Jude Nagurney <[email protected]> Julien Deniau <[email protected]> julienp <[email protected]> Julien Poissonnier <[email protected]> Jun Sakai <[email protected]> Justin Patrin <[email protected]> Justin Patrin <[email protected]> Kalle Bronsen <[email protected]> kamalgill <[email protected]> Kamil Breguła <[email protected]> Kanan Rahimov <[email protected]> Kareem Zidane <[email protected]> Keith Perkins <[email protected]> Ken Fromm <[email protected]> Ken Reese <[email protected]> keves <[email protected]> Kevin Gu <[email protected]> Kevin Harvey <[email protected]> Kevin McCarthy <[email protected]> Kevin Richardson <[email protected]> Kevin Richardson <[email protected]> Kevin Tran <[email protected]> Kieran Brownlees <[email protected]> Kirill Pavlov <[email protected]> Kirill Romanov <[email protected]> komu <[email protected]> Konstantinos Koukopoulos <[email protected]> Konstantin Podshumok <[email protected]> Kornelijus Survila <[email protected]> Kouhei Maeda <[email protected]> Kracekumar Ramaraju <[email protected]> Krzysztof Bujniewicz <[email protected]> kuno <[email protected]> Kxrr <[email protected]> Kyle Kelley <[email protected]> Laurent Peuch <[email protected]> lead2gold <[email protected]> Leo Dirac <[email protected]> Leo Singer <[email protected]> Lewis M. Kabui <[email protected]> llllllllll <[email protected]> Locker537 <[email protected]> Loic Bistuer <[email protected]> Loisaida Sam <[email protected]> lookfwd <[email protected]> Loren Abrams <[email protected]> Loren Abrams <[email protected]> Lucas Wiman <[email protected]> lucio <[email protected]> Luis Clara Gomez <[email protected]> Lukas Linhart <[email protected]> Łukasz Kożuchowski <[email protected]> Łukasz Langa <[email protected]> Łukasz Oleś <[email protected]> Luke Burden <[email protected]> Luke Hutscal <[email protected]> Luke Plant <[email protected]> Luke Pomfrey <[email protected]> Luke Zapart <[email protected]> mabouels <[email protected]> Maciej Obuchowski <[email protected]> Mads Jensen <[email protected]> Manuel Kaufmann <[email protected]> Manuel Vázquez Acosta <[email protected]> Marat Sharafutdinov <[email protected]> Marcelo Da Cruz Pinto <[email protected]> Marc Gibbons <[email protected]> Marc Hörsken <[email protected]> Marcin Kuźmiński <[email protected]> marcinkuzminski <[email protected]> Marcio Ribeiro <[email protected]> Marco Buttu <[email protected]> Marco Schweighauser <[email protected]> mariia-zelenova <[email protected]> Marin Atanasov Nikolov <[email protected]> Marius Gedminas <[email protected]> mark hellewell <[email protected]> Mark Lavin <[email protected]> Mark Lavin <[email protected]> Mark Parncutt <[email protected]> Mark Story <[email protected]> Mark Stover <[email protected]> Mark Thurman <[email protected]> Markus Kaiserswerth <[email protected]> Markus Ullmann <[email protected]> martialp <[email protected]> Martin Davidsson <[email protected]> Martin Galpin <[email protected]> Martin Melin <[email protected]> Matt Davis <[email protected]> Matthew Duggan <[email protected]> Matthew J Morrison <[email protected]> Matthew Miller <[email protected]> Matthew Schinckel <[email protected]> mattlong <[email protected]> Matt Long <[email protected]> Matt Robenolt <[email protected]> Matt Robenolt <[email protected]> Matt Williamson <[email protected]> Matt Williamson <[email protected]> Matt Wise <[email protected]> Matt Woodyard <[email protected]> Mauro Rocco <[email protected]> Maxim Bodyansky <[email protected].(none)> Maxime Beauchemin <[email protected]> Maxime Vdb <[email protected]> Mayflower <[email protected]> mbacho <[email protected]> mher <[email protected]> Mher Movsisyan <[email protected]> Michael Aquilina <[email protected]> Michael Duane Mooring <[email protected]> Michael Elsdoerfer [email protected] <[email protected].(none)> Michael Elsdorfer <[email protected]> Michael Elsdörfer <[email protected]> Michael Fladischer <[email protected]> Michael Floering <[email protected]> Michael Howitz <[email protected]> michael <[email protected]> Michael <[email protected]> michael <[email protected].(none)> Michael Peake <[email protected]> Michael Permana <[email protected]> Michael Permana <[email protected]> Michael Robellard <[email protected]> Michael Robellard <[email protected]> Michal Kuffa <[email protected]> Miguel Hernandez Martos <[email protected]> Mike Attwood <[email protected]> Mike Chen <[email protected]> Mike Helmick <[email protected]> mikemccabe <[email protected]> Mikhail Gusarov <[email protected]> Mikhail Korobov <[email protected]> Mikołaj <[email protected]> Milen Pavlov <[email protected]> Misha Wolfson <[email protected]> Mitar <[email protected]> Mitar <[email protected]> Mitchel Humpherys <[email protected]> mklauber <[email protected]> mlissner <[email protected]> monkut <[email protected]> Morgan Doocy <[email protected]> Morris Tweed <[email protected]> Morton Fox <[email protected]> Môshe van der Sterre <[email protected]> Moussa Taifi <[email protected]> mozillazg <[email protected]> mpavlov <[email protected]> mperice <[email protected]> mrmmm <[email protected]> Muneyuki Noguchi <[email protected]> m-vdb <[email protected]> nadad <[email protected]> Nathaniel Varona <[email protected]> Nathan Van Gheem <[email protected]> Nat Williams <[email protected]> Neil Chintomby <[email protected]> Neil Chintomby <[email protected]> Nicholas Pilon <[email protected]> nicholsonjf <[email protected]> Nick Eaket <[email protected]> Nick Johnson <[email protected]> Nicolas Mota <[email protected]> nicolasunravel <[email protected]> Niklas Aldergren <[email protected]> Noah Kantrowitz <[email protected]> Noel Remy <[email protected]> NoKriK <[email protected]> Norman Richards <[email protected]> NotSqrt <[email protected]> nott <[email protected]> ocean1 <[email protected]> ocean1 <[email protected]> ocean1 <[email protected]> OddBloke <[email protected]> Oleg Anashkin <[email protected]> Olivier Aubert <[email protected]> Omar Khan <[email protected]> Omer Katz <[email protected]> Omer Korner <[email protected]> orarbel <[email protected]> orf <[email protected]> Ori Hoch <[email protected]> outself <[email protected]> Pablo Marti <[email protected]> pachewise <[email protected]> partizan <[email protected]> Pär Wieslander <[email protected]> Patrick Altman <[email protected]> Patrick Cloke <[email protected]> Patrick <[email protected]> Patrick Stegmann <[email protected]> Patrick Stegmann <[email protected]> Patrick Zhang <[email protected]> Paul English <[email protected]> Paul Jensen <[email protected]> Paul Kilgo <[email protected]> Paul McMillan <[email protected]> Paul McMillan <[email protected]> Paulo <[email protected]> Paul Pearce <[email protected]> Pavel Savchenko <[email protected]> Pavlo Kapyshin <[email protected]> pegler <[email protected]> Pepijn de Vos <[email protected]> Peter Bittner <[email protected]> Peter Brook <[email protected]> Philip Garnero <[email protected]> Pierre Fersing <[email protected]> Piotr Maślanka <[email protected]> Piotr Sikora <[email protected]> PMickael <[email protected]> PMickael <[email protected]> Polina Giralt <[email protected]> precious <[email protected]> Preston Moore <[email protected]> Primož Kerin <[email protected]> Pysaoke <[email protected]> Rachel Johnson <[email protected]> Rachel Willmer <[email protected]> raducc <[email protected]> Raf Geens <[email protected]> Raghuram Srinivasan <[email protected]> Raphaël Riel <[email protected]> Raphaël Slinckx <[email protected]> Régis B <[email protected]> Remigiusz Modrzejewski <[email protected]> Rémi Marenco <[email protected]> rfkrocktk <[email protected]> Rick van Hattem <[email protected]> Rick Wargo <[email protected]> Rico Moorman <[email protected]> Rik <[email protected]> Rinat Shigapov <[email protected]> Riyad Parvez <[email protected]> rlotun <[email protected]> rnoel <[email protected]> Robert Knight <[email protected]> Roberto Gaiser <[email protected]> roderick <[email protected]> Rodolphe Quiedeville <[email protected]> Roger Hu <[email protected]> Roger Hu <[email protected]> Roman Imankulov <[email protected]> Roman Sichny <[email protected]> Romuald Brunet <[email protected]> Ronan Amicel <[email protected]> Ross Deane <[email protected]> Ross Lawley <[email protected]> Ross Patterson <[email protected]> Ross <[email protected]> Rudy Attias <[email protected]> rumyana neykova <[email protected]> Rumyana Neykova <[email protected]> Rune Halvorsen <[email protected]> Rune Halvorsen <[email protected].(none)> runeh <[email protected].(none)> Russell Keith-Magee <[email protected]> Ryan Guest <[email protected]> Ryan Hiebert <[email protected]> Ryan Kelly <[email protected]> Ryan Luckie <[email protected]> Ryan Petrello <[email protected]> Ryan P. Kelly <[email protected]> Ryan P Kilby <[email protected]> Salvatore Rinchiera <[email protected]> Sam Cooke <[email protected]> samjy <[email protected]> Sammie S. Taunton <[email protected]> Samuel Dion-Girardeau <[email protected]> Samuel Dion-Girardeau <[email protected]> Samuel GIFFARD <[email protected]> Scott Cooper <[email protected]> screeley <[email protected].(none)> sdcooke <[email protected]> Sean O’Connor <[email protected]> Sean Wang <[email protected]> Sebastian Kalinowski <[email protected]> Sébastien Fievet <[email protected]> Seong Won Mun <[email protected]> Sergey Fursov <[email protected]> Sergey Tikhonov <[email protected]> Sergi Almacellas Abellana <[email protected]> Sergio Fernandez <[email protected]> Seungha Kim <[email protected]> shalev67 <[email protected]> Shitikanth <[email protected]> Silas Sewell <[email protected]> Simon Charette <[email protected]> Simon Engledew <[email protected]> Simon Josi <[email protected]> Simon Legner <[email protected]> Simon Peeters <[email protected]> Simon Schmidt <[email protected]> skovorodkin <[email protected]> Slam <[email protected]> Smirl <[email protected]> squfrans <[email protected]> Srinivas Garlapati <[email protected]> Stas Rudakou <[email protected]> Static <[email protected]> Steeve Morin <[email protected]> Stefan hr Berder <[email protected]> Stefan Kjartansson <[email protected]> Steffen Allner <[email protected]> Stephen Weber <[email protected]> Steven Johns <[email protected]> Steven Parker <[email protected]> Steven <[email protected]> Steven Sklar <[email protected]> Steven Skoczen <[email protected]> Steven Skoczen <[email protected]> Steve Peak <[email protected]> stipa <[email protected]> sukrit007 <[email protected]> Sukrit Khera <[email protected]> Sundar Raman <[email protected]> sunfinite <[email protected]> sww <[email protected]> Tadej Janež <[email protected]> Taha Jahangir <[email protected]> Takeshi Kanemoto <[email protected]> TakesxiSximada <[email protected]> Tamer Sherif <[email protected]> Tao Qingyun <[email protected]> Tarun Bhardwaj <[email protected]> Tayfun Sen <[email protected]> Tayfun Sen <[email protected]> Tayfun Sen <[email protected]> tayfun <[email protected]> Taylor C. Richberger <[email protected]> taylornelson <[email protected]> Theodore Dubois <[email protected]> Theo Spears <[email protected]> Thierry RAMORASOAVINA <[email protected]> Thijs Triemstra <[email protected]> Thomas French <[email protected]> Thomas Grainger <[email protected]> Thomas Johansson <[email protected]> Thomas Meson <[email protected]> Thomas Minor <[email protected]> Thomas Wright <[email protected]> Timo Sugliani <[email protected]> Timo Sugliani <[email protected].(none)> Titusz <[email protected]> tnir <[email protected]> Tobias Kunze <[email protected]> Tocho Tochev <[email protected]> Tomas Machalek <[email protected]> Tomasz Święcicki <[email protected]> Tom ‘Biwaa’ Riat <[email protected]> Tomek Święcicki <[email protected]> Tom S <[email protected]> tothegump <[email protected]> Travis Swicegood <[email protected]> Travis Swicegood <[email protected]> Travis <[email protected]> Trevor Skaggs <[email protected]> Ujjwal Ojha <[email protected]> unknown Valentyn Klindukh <[email protected]> Viktor Holmqvist <[email protected]> Vincent Barbaresi <[email protected]> Vincent Driessen <[email protected]> Vinod Chandru <[email protected]> Viraj <[email protected]> Vitaly Babiy <[email protected]> Vitaly <[email protected]> Vivek Anand <[email protected]> Vlad <[email protected]> Vladimir Gorbunov <[email protected]> Vladimir Kryachko <[email protected]> Vladimir Rutsky <[email protected]> Vladislav Stepanov <[email protected]> Vsevolod <[email protected]> Wes Turner <[email protected]> wes <[email protected]> Wes Winham <[email protected]> w- <[email protected]> whendrik <[email protected]> Wido den Hollander <[email protected]> Wieland Hoffmann <[email protected]> Wiliam Souza <[email protected]> Wil Langford <[email protected]> William King <[email protected]> Will <[email protected]> Will Thompson <[email protected]> winhamwr <[email protected]> Wojciech Żywno <[email protected]> W. Trevor King <[email protected]> wyc <[email protected]> wyc <[email protected]> xando <[email protected]> Xavier Damman <[email protected]> Xavier Hardy <[email protected]> Xavier Ordoquy <[email protected]> xin li <[email protected]> xray7224 <[email protected]> y0ngdi <[email protected]> Yan Kalchevskiy <[email protected]> Yohann Rebattu <[email protected]> Yoichi NAKAYAMA <[email protected]> Yuhannaa <[email protected]> YuLun Shih <[email protected]> Yury V. Zaytsev <[email protected]> Yuval Greenfield <[email protected]> Zach Smith <[email protected]> Zhang Chi <[email protected]> Zhaorong Ma <[email protected]> Zoran Pavlovic <[email protected]> ztlpn <[email protected]> 何翔宇(Sean Ho) <[email protected]> 許邱翔 <[email protected]>


This wall was automatically generated from git history, so sadly it doesn’t not include the people who help with more important things like answering mailing-list questions.

Important Notes

Supported Python Versions

The supported Python Versions are:

  • CPython 2.7
  • CPython 3.4
  • CPython 3.5
  • CPython 3.6
  • PyPy 5.8 (pypy2)


Result Backends

New Redis Sentinel Results Backend

Redis Sentinel provides high availability for Redis. A new result backend supporting it was added.

Cassandra Results Backend

A new cassandra_options configuration option was introduced in order to configure the cassandra client.

See Cassandra backend settings for more information.

DynamoDB Results Backend

A new dynamodb_endpoint_url configuration option was introduced in order to point the result backend to a local endpoint during development or testing.

See AWS DynamoDB backend settings for more information.

Python 2/3 Compatibility Fixes

Both the CouchDB and the Consul result backends accepted byte strings without decoding them to Unicode first. This is now no longer the case.


Multiple bugs were resolved resulting in a much smoother experience when using Canvas.


Bound Tasks as Error Callbacks

We fixed a regression that occurred when bound tasks are used as error callbacks. This used to work in Celery 3.x but raised an exception in 4.x until this release.

In both 4.0 and 4.1 the following code wouldn’t work:

@app.task(name="raise_exception", bind=True)
def raise_exception(self):
    raise Exception("Bad things happened")

@app.task(name="handle_task_exception", bind=True)
def handle_task_exception(self):
    print("Exception detected")

subtask = raise_exception.subtask()


Task Representation

  • Shadowing task names now works as expected. The shadowed name is properly presented in flower, the logs and the traces.
  • argsrepr and kwargsrepr were previously not used even if specified. They now work as expected. See Hiding sensitive information in arguments for more information.

Custom Requests

We now allow tasks to use custom request classes for custom task classes.

See Requests and custom requests for more information.

Retries with Exponential Backoff

Retries can now be performed with exponential backoffs to avoid overwhelming external services with requests.

See Automatic retry for known exceptions for more information.

Sphinx Extension

Tasks were supposed to be automatically documented when using Sphinx’s Autodoc was used. The code that would have allowed automatic documentation had a few bugs which are now fixed.

Also, The extension is now documented properly. See Documenting Tasks with Sphinx for more information.