Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
A Brief History of Channels
Search
Andrew Godwin
March 31, 2016
Programming
2
2.4k
A Brief History of Channels
A talk I gave at DjangoCon Europe 2016
Andrew Godwin
March 31, 2016
Tweet
Share
More Decks by Andrew Godwin
See All by Andrew Godwin
Reconciling Everything
andrewgodwin
1
260
Django Through The Years
andrewgodwin
0
160
Writing Maintainable Software At Scale
andrewgodwin
0
390
A Newcomer's Guide To Airflow's Architecture
andrewgodwin
0
310
Async, Python, and the Future
andrewgodwin
2
610
How To Break Django: With Async
andrewgodwin
1
660
Taking Django's ORM Async
andrewgodwin
0
670
The Long Road To Asynchrony
andrewgodwin
0
590
The Scientist & The Engineer
andrewgodwin
1
690
Other Decks in Programming
See All in Programming
わたしの星のままで一番星になる ~ 出産を機にSIerからEC事業会社に転職した話 ~
kimura_m_29
0
180
【re:Growth 2024】 Aurora DSQL をちゃんと話します!
maroon1st
0
770
コンテナをたくさん詰め込んだシステムとランタイムの変化
makihiro
1
120
「Chatwork」Android版アプリを 支える単体テストの現在
okuzawats
0
180
HTTP compression in PHP and Symfony apps
dunglas
2
1.7k
ゆるやかにgolangci-lintのルールを強くする / Kyoto.go #56
utgwkk
1
350
Асинхронность неизбежна: как мы проектировали сервис уведомлений
lamodatech
0
600
103 Early Hints
sugi_0000
1
220
MCP with Cloudflare Workers
yusukebe
2
220
似たもの同士のPerlとPHP
uzulla
1
130
命名をリントする
chiroruxx
1
380
.NET 9アプリをCGIとして レンタルサーバーで動かす
mayuki
1
770
Featured
See All Featured
Done Done
chrislema
181
16k
ピンチをチャンスに:未来をつくるプロダクトロードマップ #pmconf2020
aki_iinuma
111
49k
Dealing with People You Can't Stand - Big Design 2015
cassininazir
365
25k
Fontdeck: Realign not Redesign
paulrobertlloyd
82
5.3k
Navigating Team Friction
lara
183
15k
JavaScript: Past, Present, and Future - NDC Porto 2020
reverentgeek
47
5.1k
Chrome DevTools: State of the Union 2024 - Debugging React & Beyond
addyosmani
2
160
Mobile First: as difficult as doing things right
swwweet
222
9k
Performance Is Good for Brains [We Love Speed 2024]
tammyeverts
6
510
It's Worth the Effort
3n
183
28k
Exploring the Power of Turbo Streams & Action Cable | RailsConf2023
kevinliebholz
28
4.3k
The Invisible Side of Design
smashingmag
298
50k
Transcript
Andrew Godwin @andrewgodwin BRIEF HISTORY of CHANNELS A
Andrew Godwin Hi, I'm Django core developer Senior Software Engineer
at Likes networking a little bit too much
Channels
Channels?
WebSocket
HTTP 1 request response Browser Server request response request response
request response
HTTP 2 request response Browser Server request response request 1
response 2 request 2 response 1
WSGI request response Browser Server Django call app return val
WebSockets receive send Browser Server send receive send send
receive send Browser Server send receive send send Django ?
Hard to deadlock Built-in authorisation Scales down Widely deployable Optional
Django is not built for this.
But what if it was?
Instead of requests, we have events
Events of the same type are grouped on a named
channel
HTTP requests HTTP responses WebSocket connecteds WebSocket frames received WebSocket
frames sent WebSocket disconnections
A channel is a: named, first-in-first-out, at-most-once, non-broadcast, network-transparent queue
of messages
http.request Protocol Server Worker Server http.response websocket.connect websocket.send websocket.receive websocket.send
websocket.send
Responses are on single-reader channels (http.response!1A2B3C)
You can send onto channels from anywhere
How do you use it?
View request response callable
Consumer event event callable event event
Every message on a channel runs the consumer function
http.request routes to a view system consumer
def ws_message(message): # Get things from message data = json.loads(message['text'])
# Use ORM like normal MyModel.objects.create( value=data['value'], ) # Send a reply and close socket message.reply_channel.send({ 'text': 'OK', 'close': True, })
routing.py: urls.py for Channels
message.user: like request.user
message.channel_session: per-socket sessions
Groups broadcast/pub-sub
Add a channel to a Group Remove a channel from
a Group Send to a Group
Worked Examples github.com/andrewgodwin/channels-examples
Liveblog http.request Django view layer websocket.connect Add to liveblog Group
websocket.disconnect Remove from liveblog Group <Article.save> Send notification to liveblog
Chat http.request Django view layer websocket.receive Either add to room
Group or send to chat_messages websocket.disconnect Remove from room Groups chat_messages Send to room Groups
It's so easy to join! CALL NOW
Things I didn't even get to: Replacing WSGI Pluggable channel
backends Sharding and scaling It's still just runserver
A base for the future Scheduler? Retry logic? Generic Consumers?
...and much more
1.10 "Provisional"?
1.8 1.9 pip install channels
channels.readthedocs.com github.com/andrewgodwin/channels-examples
Thanks. Andrew Godwin @andrewgodwin