i am trying to wrap my head around scopes, still. most examples online are simplistic uses of `runBl...

# coroutines

[projectmoon]

i am trying to wrap my head around scopes, still. most examples online are simplistic uses of runBlocking... use case here is that i need to, once a day run a bunch of operations as coroutines. currently this is a java scheduled executor, but i want to switch to coroutines for the actual running of the code.

[projectmoon]

i am thinking of using runBlocking and a bunch of launch calls inside of this

[Dico]

runBlocking scope has only 1 thread.
Use a scope like this,
val scope = CoroutineScope(SupervisorJob() + Dispatchers.Default)
Then
scope.launch { /*worker code */}

[projectmoon]

that looks about what i'm after, yes. the scope object is then used to join/wait/kill all the threads?

[projectmoon]

when scope dies, so does everything underneath

[projectmoon]

are there any built-ins of the corutine API for running a coroutine at a specific time? i know there is timer, but otherwise i guess i can use a scheduling library to actually fire up the workers

[Dico]

You can use the delay function after starting the coroutine

[projectmoon]

yes, couldu use that. although it's more like i have to schedule according to cron-esque policies

[projectmoon]

actually i can use delay + next execution time from spring scheduling, i think

[Dico]

If you want things to happen at a particular time, you might be better off using cron jobs to start a process

[projectmoon]

that is the most reliable approach, yes. right now i am just experimenting. but i want to in the end leverage a higher level cron facility

[gildor]

Use scope like this

I don't see why scope is needed in this case, just GlobalScope is fine for non cancellable scope of some background tasks

[Dico]

I wouldn't recommend using GlobalScope to someone who doesn't understand scopes

[gildor]

I wouldn’t recommend to use val scope = CoroutineScope(SupervisorJob() + Dispatchers.Default) to someone who doesn’t understand scopes

[gildor]

it doesn’t add any value or safety, just more code

[gildor]

sure, you can cancel scope, but in this sample you also easily can cancel Job

[Dico]

It's just a decent example of what a scope can do and as should be evident, he immediately had a better idea of what scopes do

[gildor]

Fair enough

[projectmoon]

the proper solution is probably a supervisor scope, but right now i am just experimenting with converting a standard java scheduled executor service into something using coroutines

[projectmoon]

unfortunately all of this is backed by JPA at the moment, and the R2DBC library is not yet stable. so, i am not sure building coroutines on top will help that much

[Dico]

You can use executor.asCoroutineDispatcher() instead of Dispatchers.Default

[projectmoon]

that would be a good place to begin bridging