Sharing Outpost

[sebt3]

Outpost cost ressources (since they are create deployments).
Authentik clearly allow to share an outpost between many provider/application.

Yet I don't see a single way to do this using this provider.

The official kubernetes provider allow to modify existing object using :
https://registry.terraform.io/providers/hashicorp/kubernetes/latest/docs/resources/labels

Something related to this would help a lot.

a bit related to #341 or #310.
But the options of creating a new outpost for every application willing to use authentik is clearly not viable.

[BeryJu]

You can reference multiple providers via the protocol_providers attribute, which will assign all the providers to the outpost

[sebt3]

Sure thing I can put as much providers in the outpost when I create it, but I cannot add more afterward.
Workflow :

• 1 terraform layer containing authentik
• 1 terraform layer per application connected to it.

Currently, as a workaround, i'm using restapi provider in tandem with the http provider to work around this :

locals {
  request_headers = {
    "Content-Type"  = "application/json"
    Authorization   = "Bearer ${local.authentik-token}"
  }
  ldap-outpost-prividers = jsondecode(data.http.get_ldap_outpost.response_body).results[0].providers
  ldap-outpost-pk = jsondecode(data.http.get_ldap_outpost.response_body).results[0].pk
}

data "http" "get_ldap_outpost" {
  url    = "http://authentik.${var.authentik-ns}.svc/api/v3/outposts/instances/?name__iexact=ldap"
  method = "GET"
  request_headers = local.request_headers
  lifecycle {
    postcondition {
      condition     = contains([200], self.status_code)
      error_message = "Status code invalid"
    }
  }
}

provider "restapi" {
  uri = "http://authentik.${var.authentik-ns}.svc/api/v3/"
  headers = local.request_headers
  create_method = "PATCH"
  update_method = "PATCH"
  destroy_method = "PATCH"
  write_returns_object = true
  id_attribute = "name"
}

resource "restapi_object" "ldap_outpost_binding" {
  path = "/outposts/instances/${local.ldap-outpost-pk}/"
  data = jsonencode({
    name = "ldap"
    providers = contains(local.ldap-outpost-prividers, authentik_provider_ldap.gitea_provider_ldap.id) ? local.ldap-outpost-prividers : concat(local.ldap-outpost-prividers, [authentik_provider_ldap.gitea_provider_ldap.id])
  })
}

note the conditionnal concatenation of the arrays.
I still have to do the same in the authentik layer so an update of the layer wont reset the outpost configuration

[sebt3]

Current implementation for the authentik layer (only using the http provider and the authentik one) :

locals {
  request_headers = {
    "Content-Type"  = "application/json"
    Authorization   = "Bearer ${local.authentik-token}"
  }
  ldap-outpost-json = jsondecode(data.http.get_ldap_outpost.response_body).results
  ldap-outpost-prividers = length(local.ldap-outpost-json)>0?(contains(local.ldap-outpost-json[0].providers, authentik_provider_ldap.provider_ldap[0].id)?local.ldap-outpost-json[0].providers:concat(local.ldap-outpost-json[0].providers, [authentik_provider_ldap.provider_ldap[0].id])):[authentik_provider_ldap.provider_ldap[0].id]
}

data "http" "get_ldap_outpost" {
  depends_on = [kustomization_resource.post, authentik_provider_ldap.provider_ldap]
  url    = "http://authentik.${var.namespace}.svc/api/v3/outposts/instances/?name__iexact=ldap"
  method = "GET"
  request_headers = local.request_headers
  lifecycle {
    postcondition {
      condition     = contains([200], self.status_code)
      error_message = "Status code invalid"
    }
  }
}

resource "authentik_service_connection_kubernetes" "local" {
  count = var.outposts.ldap ? 1 : 0
  name  = "local"
  local = true
}

resource "authentik_provider_ldap" "provider_ldap" {
  count = var.outposts.ldap ? 1 : 0
  name         = "authentik-ldap-provider"
  base_dn      = "dc=${var.namespace},dc=namespace"
  bind_flow    = authentik_flow.ldap-authentication-flow.uuid
}

resource "authentik_outpost" "outpost-ldap" {
  count = var.outposts.ldap ? 1 : 0
  name = "ldap"
  type = "ldap"
  service_connection = authentik_service_connection_kubernetes.local[count.index].id
  config = jsonencode({
    "log_level": "info",
    "authentik_host": "http://authentik",
    "docker_map_ports": true,
    "kubernetes_replicas": 1,
    "kubernetes_namespace": var.namespace,
    "authentik_host_browser": "",
    "object_naming_template": "ak-outpost-%(name)s",
    "authentik_host_insecure": false,
    "kubernetes_service_type": "ClusterIP",
    "kubernetes_image_pull_secrets": [],
    "kubernetes_disabled_components": [],
    "kubernetes_ingress_annotations": {},
    "kubernetes_ingress_secret_name": "authentik-outpost-tls"
  })
  protocol_providers = local.ldap-outpost-prividers
}

Note that the ressource authentik_provider_ldap.provider_ldap is a forced dummy one that will never be used.

[sebt3]

So in my opinion, if that workflow was to be supported, the requierement would be :

• some keys in the authentik_outpost ressource to say that the provider list should at least contain the given provider without removing the others.
• some "add-provider-to-outpost" ressource to add additional providers later on

that's my opinion, nothing more, and, as seen above I have a working implementation so :P