New to backstage and attempting setup I am exposing at a sub

Question

New to backstage and attempting setup I am exposing at a sub path which appears to be supported However with my app config local yaml set as follows ``` app Should be the same as backend baseUrl when using the `app backend` plugin baseUrl backend Note that the baseUrl should be the URL that the browser and other clients should use when communicating with the backend i e it needs to be reachable not just from within the backend host but from all of your callers When its value is it s strictly private and can t be reached by others baseUrl ``` If I navigate to the main URL I just get a blank page If I looked at the returned HTML ```< doctype html> lt html lang= en gt lt head gt lt meta charset= utf 8 gt lt meta name= viewport content= width=device width initial scale=1 gt lt meta name= theme color content= 000000 gt lt meta name= description content= Backstage is an open platform for building developer portals gt lt link rel= apple touch icon href= logo192 png gt lt link rel= manifest href= manifest json crossorigin= use credentials gt lt link rel= icon href= favicon ico gt lt link rel= shortcut icon href= favicon ico gt lt link rel= apple touch icon sizes= 180x180 href= apple touch icon png gt lt link rel= icon type= image png sizes= 32x32 href= favicon 32x32 png gt lt link rel= icon type= image png sizes= 16x16 href= favicon 16x16 png gt lt link rel= mask icon href= safari pinned tab svg color= 5bbad5 gt lt title gt Scaffolded Backstage App lt title gt lt script defer= defer src= static runtime ca7de487 js gt lt script gt lt script defer= defer src= static module material ui d6133835 js gt lt script gt lt script defer= defer src= static module lodash 2cb4e330 js gt lt script gt lt script defer= defer src= static module date fns 09dcdd7d js gt lt script gt lt script defer= defer src= static module backstage 958f85a5 js gt lt script gt lt script defer= defer src= static module yaml bcdcfe65 js gt lt script gt lt script defer= defer src= static module material table a69dfac1 js gt lt script gt lt script defer= defer src= static module luxon 709b2632 js gt lt script gt lt script defer= defer src= static module octokit 37e435bf js gt lt script gt lt script defer= defer src= static module zod c5bfa0d3 js gt lt script gt lt script defer= defer src= static module react dom fcbc6a60 js gt lt script gt lt script defer= defer src= static module react beautiful dnd 1bd1bde2 js gt lt script gt lt script defer= defer src= static module remix run df093bf6 js gt lt script gt lt script defer= defer src= static vendor ca7de487 js gt lt script gt lt script defer= defer src= static main ca7de487 js gt lt script gt lt head gt lt body gt lt noscript gt You need to enable JavaScript to run this app lt noscript gt lt div id= root gt lt div gt lt body gt lt html gt ``` You can see that none of the URL are correctly rendered with the sub path

Asaf Erlich · Answer

I don t understand your goal The base url is used by the backend or frontend process or pods only to hit the backends You should be hitting the nearest one It looks like you re making it the external facing url That means each time a frontend or backend process wants to hit the backend it has to go out to the load balancer again Why

Matt Ceroni · Answer

< Asaf Erlich> I am a newbie to backstage so I might not be understanding the setting I read `Note that the baseUrl should be the URL that the browser and` and assumed that means the the URL I put into my browser to access the backstage UI Right now I am just trying to get basic setup done and expose the UI deployed in Kubernetes through an ingress and the URL at which that is configured in the ingress controller is How would I configure that URL so that backstage correctly serves paths

Asaf Erlich · Answer

Yeah I read that comment but it does not match my understanding of that configuration value at all

Asaf Erlich · Answer

I don t know why any browser or client would care what s in your app config The app config is included in the backstage container and read by the app both backend and frontend processes on startup

Asaf Erlich · Answer

I would suggest for now to leave the backend base url to whatever is the default and only modify it if necessary

Asaf Erlich · Answer

Hmm I take it back

Asaf Erlich · Answer

I m sorry looking in my configuration we do point this at the same one as the external facing URL

Asaf Erlich · Answer

I guess I m wrong

Matt Ceroni · Answer

No worries It is a bit confusing

Asaf Erlich · Answer

our local configuration is not this way so I was confused

Asaf Erlich · Answer

we have one for local one for stage one for prod

Asaf Erlich · Answer

so I mixed things up

Matt Ceroni · Answer

I can see what you are saying about backend url

Matt Ceroni · Answer

Like why would I force that to go external back through LB

Asaf Erlich · Answer

I must be mixing up details

Matt Ceroni · Answer

but app baseUrl is the URL at which clients interact with the front end UI And the GitHub link above seems to suggest that you should be able to add a sub path

Matt Ceroni · Answer

But that doesn t seem to be working for me In your config do you have a sub path

Asaf Erlich · Answer

we don t add a sub path

Matt Ceroni · Answer

Ok

Asaf Erlich · Answer

but I don t see why it would matter

Asaf Erlich · Answer

unless it s parsing it in some way

Matt Ceroni · Answer

One last quick question if you don t mind By default Backstage reads app config yaml and app config local yaml But I see some indication that you can specify APP ENV and have it read app config $APP ENV yaml ex app config production yaml Do you use that functionality or are you putting all your settings in app config yaml

Matt Ceroni · Answer

I think the sub path matters because the initial page returned contains links to Javascript images and such and if they don t set the sub path correctly then you get 404 which I get

Asaf Erlich · Answer

sorry I didn t look at this message until now

Asaf Erlich · Answer

We prefer keeping everything in app config files and only rely on the env variable overrides in rare cases We found it s easier to manage the files in git We have the following app config files ```fd app config app config local yaml app config yaml config app config local yaml config app config production yaml config app config stage yaml``` The first is actually a symlink to the one inside the config folder In the startup command for the container we actually pass in the flags ` config app config yaml config config app config lt env gt yaml` and we have different ones for stage and prod

Asaf Erlich · Answer

If that makes sense