# Which Problems Are Solved
ZITADEL currently selects the instance context based on a HTTP header
(see https://github.com/zitadel/zitadel/issues/8279#issue-2399959845 and
checks it against the list of instance domains. Let's call it instance
or API domain.
For any context based URL (e.g. OAuth, OIDC, SAML endpoints, links in
emails, ...) the requested domain (instance domain) will be used. Let's
call it the public domain.
In cases of proxied setups, all exposed domains (public domains) require
the domain to be managed as instance domain.
This can either be done using the "ExternalDomain" in the runtime config
or via system API, which requires a validation through CustomerPortal on
zitadel.cloud.
# How the Problems Are Solved
- Two new headers / header list are added:
- `InstanceHostHeaders`: an ordered list (first sent wins), which will
be used to match the instance.
(For backward compatibility: the `HTTP1HostHeader`, `HTTP2HostHeader`
and `forwarded`, `x-forwarded-for`, `x-forwarded-host` are checked
afterwards as well)
- `PublicHostHeaders`: an ordered list (first sent wins), which will be
used as public host / domain. This will be checked against a list of
trusted domains on the instance.
- The middleware intercepts all requests to the API and passes a
`DomainCtx` object with the hosts and protocol into the context
(previously only a computed `origin` was passed)
- HTTP / GRPC server do not longer try to match the headers to instances
themself, but use the passed `http.DomainContext` in their interceptors.
- The `RequestedHost` and `RequestedDomain` from authz.Instance are
removed in favor of the `http.DomainContext`
- When authenticating to or signing out from Console UI, the current
`http.DomainContext(ctx).Origin` (already checked by instance
interceptor for validity) is used to compute and dynamically add a
`redirect_uri` and `post_logout_redirect_uri`.
- Gateway passes all configured host headers (previously only did
`x-zitadel-*`)
- Admin API allows to manage trusted domain
# Additional Changes
None
# Additional Context
- part of #8279
- open topics:
- "single-instance" mode
- Console UI
* feat(api): feature API proto definitions
* update proto based on discussion with @livio-a
* cleanup old feature flag stuff
* authz instance queries
* align defaults
* projection definitions
* define commands and event reducers
* implement system and instance setter APIs
* api getter implementation
* unit test repository package
* command unit tests
* unit test Get queries
* grpc converter unit tests
* migrate the V1 features
* migrate oidc to dynamic features
* projection unit test
* fix instance by host
* fix instance by id data type in sql
* fix linting errors
* add system projection test
* fix behavior inversion
* resolve proto file comments
* rename SystemDefaultLoginInstanceEventType to SystemLoginDefaultOrgEventType so it's consistent with the instance level event
* use write models and conditional set events
* system features integration tests
* instance features integration tests
* error on empty request
* documentation entry
* typo in feature.proto
* fix start unit tests
* solve linting error on key case switch
* remove system defaults after discussion with @eliobischof
* fix system feature projection
* resolve comments in defaults.yaml
---------
Co-authored-by: Livio Spring <livio.a@gmail.com>
