Redirect URI not using serviceRootUrl

[SirBubbls]

We serve the a frost server instance in Kubernetes under a subpath https://<domain>/path/ the serviceRootUrl appears to be correct.

INFO   d.f.i.ilt.frostserver.settings.Settings - Setting serviceRootUrl has value 'https://<domain>/path/'

The Frost instance is also reachable under this path. Unfortunately integrating Keycloak introduces issues with the redirect_uri. The auth request to Keycloak is http://<daomin>/FROST-Server (https://<domain>/auth/realms/<redacted>/protocol/openid-connect/auth?response_type=code&client_id=<redacted>&redirect_uri=http://<domain>/FROST-Server/<redacted>&login=true&scope=openid). Because we don't serve Frost under this path, the authentication fails. As soon as we serve Frost under http://<domain>/ the login succeeds.
Is there a configuration option for a subpath in the redirect_uri that i am missing or is this a bug?

[hylkevds]

That redirect_uri is generated by the Keycloak filter, based on the configuration in auth.keycloakConfig[Url/File].
Looking at the KeyCloak docs I suspect you will need to tune the redirect-rewrite-rules parameter.

[SirBubbls]

Thanks for the quick response. We tried using the redirect-rewrite-rules for rewriting http to https. For some reason this didn't work and we dismissed the idea. I tried it again because of your comment and adding a subpath is indeed possible.

"redirect-rewrite-rules": {
    "^(.*)\/FROST-Server(.*)$": "$1/<subpath>/FROST-Server$2"
  }

The redirect_uri is now correct but we run into an infinite redirect loop as soon as we do the authentication flow from our subpath instead of <domain>/FROST-Server. I did some digging and suspect that the path attribute for the JSESSIONID is not correctly set by the Frost server.

{
	"Response Cookies": {
		"JSESSIONID": {
			"httpOnly": true,
			"path": "/FROST-Server",  // this should be /<subpath>/FROST-Server doesn't it?
			"value": "..."
		},
		"OAuth_Token_Request_State": {
			"httpOnly": true,
			"path": "/",
			"value": "..."
		}
	}
}

[hylkevds]

Hmm, it seems Tomcat uses the path that Tomcat sees for the session cookie, but this doesn't match the path the client sees.
Tomcat does have the option sessionCookiePath to configure this.
We'll have to find a way to make this configurable from the outside...