https://kotlinlang.org logo
Channels
100daysofcode
100daysofkotlin
100daysofkotlin-2021
advent-of-code
aem
ai
alexa
algeria
algolialibraries
amsterdam
android
android-architecture
android-databinding
android-studio
androidgithubprojects
androidthings
androidx
androidx-xprocessing
anime
anko
announcements
apollo-kotlin
appintro
arabic
argentina
arkenv
arksemdevteam
armenia
arrow
arrow-contributors
arrow-meta
ass
atlanta
atm17
atrium
austin
australia
austria
awesome-kotlin
ballast
bangladesh
barcelona
bayarea
bazel
beepiz-libraries
belgium
benchmarks
berlin
big-data
books
boston
brazil
brikk
budapest
build
build-tools
bulgaria
bydgoszcz
cambodia
canada
carrat
carrat-dev
carrat-feed
chicago
chile
china
chucker
cincinnati-user-group
cli
clikt
cloudfoundry
cn
cobalt
code-coverage
codeforces
codemash-precompiler
codereview
codingame
codingconventions
coimbatore
collaborations
colombia
colorado
communities
competitive-programming
competitivecoding
compiler
compose
compose-android
compose-desktop
compose-hiring
compose-ios
compose-mp
compose-ui-showcase
compose-wear
compose-web
confetti
connect-audit-events
corda
cork
coroutines
couchbase
coursera
croatia
cryptography
cscenter-course-2016
cucumber-bdd
cyprus
czech
dagger
data2viz
databinding
datascience
dckotlin
debugging
decompose
decouple
denmark
deprecated
detekt
detekt-hint
dev-core
dfw
docs-revamped
dokka
domain-driven-design
doodle
dsl
dublin
dutch
eap
eclipse
ecuador
edinburgh
education
effective-kotlin
effectivekotlin
emacs
embedded-kotlin
estatik
event21-community-content
events
exposed
failgood
fb-internal-demo
feed
firebase
flow
fluid-libraries
forkhandles
forum
fosdem
fp-in-kotlin
framework-elide
freenode
french
fritz2
fuchsia
functional
funktionale
gamedev
ge-kotlin
general-advice
georgia
geospatial
german-lang
getting-started
github-workflows-kt
glance
godot-kotlin
google-io
gradle
graphic
graphkool
graphql
graphql-kotlin
graviton-browser
greece
grpc
gsoc
gui
hackathons
hacktoberfest
hamburg
hamkrest
helios
helsinki
hexagon
hibernate
hikari-cp
hire-me
hiring
hongkong
hoplite
http4k
hungary
hyderabad
image-processing
india
indonesia
inkremental
intellij
intellij-plugins
intellij-tricks
internships
introduce-yourself
io
ios
iran
israel
istanbulcoders
italian
jackson-kotlin
jadx
japanese
jasync-sql
java-to-kotlin-refactoring
javadevelopers
javafx
javalin
javascript
jdbi
jhipster-kotlin
jobsworldwide
jpa
jshdq
juul-libraries
jvm-ir-backend-feedback
jxadapter
k2-early-adopters
kaal
kafka
kakao
kalasim
kapt
karachi
karg
karlsruhe
kash_shell
kaskade
kbuild
kdbc
kgen-doc-tools
kgraphql
kinta
klaxon
klock
kloudformation
kmdc
kmm-español
kmongo
knbt
knote
koalaql
koans
kobalt
kobweb
kodein
kodex
kohesive
koin
koin-dev
komapper
kondor-json
kong
kontent
kontributors
korau
korean
korge
korim
korio
korlibs
korte
kotest
kotest-contributors
kotless
kotlick
kotlin-asia
kotlin-beam
kotlin-by-example
kotlin-csv
kotlin-data-storage
kotlin-foundation
kotlin-fuel
kotlin-in-action
kotlin-inject
kotlin-latam
kotlin-logging
kotlin-multiplatform-contest
kotlin-mumbai
kotlin-native
kotlin-pakistan
kotlin-plugin
kotlin-pune
kotlin-roadmap
kotlin-samples
kotlin-sap
kotlin-serbia
kotlin-spark
kotlin-szeged
kotlin-website
kotlinacademy
kotlinbot
kotlinconf
kotlindl
kotlinforbeginners
kotlingforbeginners
kotlinlondon
kotlinmad
kotlinprogrammers
kotlinsu
kotlintest
kotlintest-devs
kotlintlv
kotlinultimatechallenge
kotlinx-datetime
kotlinx-files
kotlinx-html
kotrix
kotson
kovenant
kprompt
kraph
krawler
kroto-plus
ksp
ktcc
ktfmt
ktlint
ktor
ktp
kubed
kug-leads
kug-torino
kvision
kweb
lambdaworld_cadiz
lanark
language-evolution
language-proposals
latvia
leakcanary
leedskotlinusergroup
lets-have-fun
libgdx
libkgd
library-development
lincheck
linkeddata
lithuania
london
losangeles
lottie
love
lychee
macedonia
machinelearningbawas
madrid
malaysia
mathematics
meetkotlin
memes
meta
metro-detroit
mexico
miami
micronaut
minnesota
minutest
mirror
mockk
moko
moldova
monsterpuzzle
montreal
moonbean
morocco
motionlayout
mpapt
mu
multiplatform
mumbai
munich
mvikotlin
mvrx
myndocs-oauth2-server
naming
navigation-architecture-component
nepal
new-mexico
new-zealand
newname
nigeria
nodejs
norway
npm-publish
nyc
oceania
ohio-kotlin-users
oldenburg
oolong
opensource
orbit-mvi
osgi
otpisani
package-search
pakistan
panamá
pattern-matching
pbandk
pdx
peru
philippines
phoenix
pinoy
pocketgitclient
polish
popkorn
portugal
practical-functional-programming
proguard
prozis-android-backup
pyhsikal
python
python-contributors
quasar
random
re
react
reaktive
realm
realworldkotlin
reductor
reduks
redux
redux-kotlin
refactoring-to-kotlin
reflect
refreshversions
reports
result
rethink
revolver
rhein-main
rocksdb
romania
room
rpi-pico
rsocket
russian
russian_feed
russian-kotlinasfirst
rx
rxjava
san-diego
science
scotland
scrcast
scrimage
script
scripting
seattle
serialization
server
sg-user-group
singapore
skia-wasm-interop-temp
skrape-it
slovak
snake
sofl-user-group
southafrica
spacemacs
spain
spanish
speaking
spek
spin
splitties
spotify-mobius
spring
spring-security
squarelibraries
stackoverflow
stacks
stayhungrystayfoolish
stdlib
stlouis
strife-discord-lib
strikt
students
stuttgart
sudan
swagger-gradle-codegen
swarm
sweden
swing
swiss-user-group
switzerland
talking-kotlin
tallinn
tampa
teamcity
tegal
tempe
tensorflow
terminal
test
testing
testtestest
texas
tgbotapi
thailand
tornadofx
touchlab-tools
training
tricity-kotlin-user-group
trójmiasto
truth
tunisia
turkey
turkiye
twitter-feed
uae
udacityindia
uk
ukrainian
uniflow
unkonf
uruguay
utah
uuid
vancouver
vankotlin
vertx
videos
vienna
vietnam
vim
vkug
vuejs
web-mpp
webassembly
webrtc
wimix_sentry
wwdc
zircon
Powered by
Title
p

Parijat Shah

03/23/2023, 9:14 PM
Hello. Is there anyway to enable pings in Apollo kotlin client for websocket? I am running into problem while using subscription when device goes into sleep mode. Our backend sends a message at fixed interval but when device goes into sleep mode, network turns off and eventually our backend will give up without ack and closes the connection. In the client, since network is off FIN is never received . When eventually device wakes up, if client is sending pings, it will get exception on write and hopefully will be handled by establishing a new socket connection. Without ping/exception, I have a stale connection.
m

mbonnin

03/23/2023, 9:22 PM
Depends your protocol.
GraphQLWsProtocol
has
pingPayload
and
pongPayload
(source )
More generally, I'd recommend closing the subscription when the device goes in deep sleep. If you run your subscriptions in
viewModelScope
that should be done automatically
p

Parijat Shah

03/27/2023, 4:47 PM
Hi Martin. I confirmed that exception is actually thrown eventually when device goes into sleep mode. I was wrong concluding that it is not thrown after finding out that even with
webSocketReopenWhen
subscription never recovers when device comes off the sleep mode. I looked at the source code
SubscriptionWsProtocol.kt
, `WsProtocol.kt`&
WebSocketNetworkTransport.kt
and did some digging in and here is my findings. 1. When devices goes into sleep mode, java.net.SocketException ( software caused connection abort ) is thrown in WsProtocol on line number 149 in method
run
2. In the WebSocketNetworkTransport.kt, on line
151
, we have a
while(true)
block, that consumes messages produced by
message
channel 3. When exception ( java.net.SocketException ) is thrown, the message of type
NetworkError
is received as expected, and since we have enabled
webSocketReopenWhen
the following code on line
157
gets executed.
if (reopenWhen?.invoke(message.cause, reopenAttemptCount) == true) {
              reopenAttemptCount++
              activeMessages.values.forEach {
                // Re-queue all start messages
                // This will restart the websocket
                messages.trySend(it)
              }
            }
We have like 5 active subscriptions, so this will run 5 times , sending 5 messages of type
Command
. Each of the messages will be handled by trying to create
protocol
and initializing
connection
line number
203 to 215
But since the device is still in the sleep mode, exception is thrown
try {
              protocol!!.connectionInit()
            } catch (e: Exception) {
              // Error initializing the connection
              protocol = null
              messages.send(NetworkError(e))
              continue
            }
This will result in 5 more messages of type
NetworkError
being send to the channel. At this point, you will have 5 messages. At the next iteration, line
152
the next message is received which we know is of type
Network Error
, the same
reopenWhen
on line
157
will get executed, but here just 1
Network Error
message, will now result in
5
messages of type
Command
so when all
5
network error messages are received, we have already sent
25
messages of type
Command
If the device is still in the sleep mode, these 25 messages of type
Command
will result in another
25
messages of type
Network Error
if you have 60 seconds delay for your
reopenWhen
block, handling receiving these
25
messages will itself take
25
minutes and after that you will have
125
messages of type
Command
and which will result in another
125
messages of type
Network Error
You can see now that even after
device
comes out of sleep mode and network is available, the message of type
Command
is burried under
Network Error
messages. I think there is a need to revisit how the
network error
is handled, one way could be to dedupe the messages. There is no need to send the
same
message 125 times when all that you need is
one
for logic to work.
m

mbonnin

03/27/2023, 6:26 PM
Thanks for the thorough review!
What I don't understand is how come you continue enqueuing messaging while
reopenWhen?.invoke(message.cause, reopenAttemptCount)
is running. It's a single message queue so if you suspend 60s in
reopenWhen
then no other message can be queued?
I know it's not easy with subscriptions but if you have a reproducer, that'd help a ton
p

Parijat Shah

03/27/2023, 7:02 PM
I think I didn't put it correctly. After 60 seconds wait is over,
activeMessages.values.forEach {
                // Re-queue all start messages
                // This will restart the websocket
                messages.trySend(it)
              }

This runs 5 times since activeMessage size is 5 , the message type `Command` is sent.  
Now you are looking at Message queue : Command,Command,Command,Command,Command

Each of these will be handled by creating protocol and trying to initialize connection. Since network is still off , network exception is thrown 

messages.send(NetworkError(e))
Now you are looking at the queue NE, NE, NE, NE, NE Each of this will result in reopenWhen?. suspending for 60 seconds, but after 3 minutes , the queue will look Command, Command ...... Command ( total 25 messages ) Each of this command will result in 1 exception so you are now looking at the queue NE,NE,NE .... NE ( 25 message ) Now for each NE, you will wait 60 seconds and go through activeMessages loop, resulting in Command, Command ..... Command ( total 125 message ) If network is still off , this will result in NE, NE .. NE ( 125 message ) At this point you after 60 seconds, lets say network is back on, the message
Command
won't get processed until 125 messages of type Network Error are processed. Each of the NE requires 60 seconds of wait so we are easily looking at 2+ hours after network is back on to try and attempt to create protocol and initialize connection . This can be easily reproduced, by enabling
webSocketWhen
and turning off network once subscription starts. You will see the queue size growing rather quickly. If network is off for a long time, this queue can grow to a large number. ``````
Also you can't reproduce it with just one subscription. You need to have more than 1 the larger the size of
activeMessages
sooner you will run into the problem.
m

mbonnin

03/27/2023, 7:05 PM
I'll take a look. Do you mind opening an issue so that we keep track of this?
p

Parijat Shah

03/27/2023, 7:06 PM
How do I go about it?
p

Parijat Shah

03/27/2023, 7:07 PM
Will do that. My description of the problem may not be the best. I am not much of a writer . Hope that's ok.
m

mbonnin

03/27/2023, 7:08 PM
You'd be surprised how much more detailed your report is compared to the average bug report 🙂 .
p

Parijat Shah

03/27/2023, 7:09 PM
Ok. Will file the report then.