basic one but what s the best pattern for accessing config i

Question

basic one but what s the best pattern for accessing config in top level functions or is this just not the way to do things e g ```fun fetchInternalClientInstance I need access to application config in here ``` on a wider point could anyone link me to some resources discussing higher level application architecture with ktor as I m starting to get beyond what is covered by the Youkube example

Henry · Answer

Similarly it d also be useful to get access to the application coroutine context which is also accessible through the application instance

David Eriksson · Answer

I suggest you try to follow the setup pattern for ktor itself

Henry · Answer

makes sense it s just a big shift coming from a service oriented design

David Eriksson · Answer

I m trying to find a suitable example

David Eriksson · Answer

David Eriksson · Answer

Maybe

David Eriksson · Answer

Depends a bit what you need the config for slightly smiling face

David Eriksson · Answer

Maybe it s not a Feature similar to a middleware in ExpressJs or NET MVC you want the config for

David Eriksson · Answer

But by writing extension functions to `Application` you have all its context

mp · Answer

personally I don t like the way the ktor project guides you towards doing config I suggest just using `embeddedServer` in a main method and then you can do config any way you please Load from env vars or property files or whatever at startup and distribute the resulting config object s as you see fit

mp · Answer

I think it s a mistake to bolt that sort of lifecycle stuff reading config out of files into an HTTP server lib

Henry · Answer

thanks for responses

Henry · Answer

gt I think it s a mistake to bolt that sort of lifecycle stuff reading config out of files into an HTTP server lib this is possibly true but I m seeing what I can do with a pure ktor implementation for now

Henry · Answer

there are benefits to a tightly integrated config system as well imo

David Eriksson · Answer

Framework vs library < mp> slightly smiling face

Henry · Answer

< David Eriksson> I suppose making all my top level functions extensions on application is an option They then remain callable from routes etc

David Eriksson · Answer

I think that s the ktor way

Henry · Answer

makes sense

Henry · Answer

I ll give it a go thanks for the tip

David Eriksson · Answer

It feels pretty strange compared to the class based like Spring Boot or DropWizard

Henry · Answer

yeah it s an interesting shift in mindset

mp · Answer

The extension function way breaks down as the app grows because you d need all the various support objects Db connections etc in scope

Henry · Answer

I can well imagine that happening

mp · Answer

I maintain a demo project showing patterns I ve used in other production ktor services <https bitbucket org marshallpierce ktor demo src master >

Henry · Answer

I m already wondering about the best way to use kodein with this pattern as it s straightforward with service constructor injection

mp · Answer

key principle every component is replacable as much as possible Obviously ripping out ktor is going to be more of a pain since all the url routing would change but you could do it Same for everything else

mp · Answer

Don t like the way that project does config Or json mapping or whatever select the corresponding code press delete do what you like

mp · Answer

that said the components I ve chosen all play nicely together and if you don t want to worry about every detail you won t hate it if you just go with what I ve picked

mp · Answer

re injection with kodein or anything else just set up routes in your constructor as here <https bitbucket org marshallpierce ktor demo src 9180858c267194e6a75d39dc9e8280e3ba53777a src main kotlin org mpierce ktordemo WidgetEndpoints kt lines 27>

mp · Answer

That s using Guice but the same idea would work for anything

Henry · Answer

oh so you re using DI to inject the application object

Henry · Answer

that did seem like a viable alternative

Henry · Answer

removes the need to make all your service functions extension functions as well

Henry · Answer

well thanks again everyone

Henry · Answer

will go off and build some things

Henry · Answer

and see what happens

mp · Answer

best way to learn

Henry · Answer

quite

David Eriksson · Answer

Your demo is very interesting < mp> thanks for sharing there is certainly more than one way to do things slightly smiling face