docs: NGING Ingress Controller guide updated to cover global integration options

docs/content/guides/proxies/nginx.adoc

@@ -124,24 +124,23 @@ location = /_auth {
 
 == NGINX Ingress Controller
 
-Even one can configure an external auth server globally with vanilla NGINX, there is no way to achieve that with the https://kubernetes.github.io/ingress-nginx/[NGINX Ingress Controller]. Only route based configuration/integration is possible.
+=== Global Configuration
 
-=== Using `X-Forwarded-*` headers
+==== Using `X-Forwarded-*` headers
 
-To integrate heimdall with the NGINX Ingress Controller you can make use of the `nginx.ingress.kubernetes.io/auth-url`, `nginx.ingress.kubernetes.io/auth-response-headers` and the `nginx.ingress.kubernetes.io/auth-snippet` annotation as shown in the example below. This will result in an NGINX configuration corresponding to the integration option, described in the link:{{< relref "#_second_option" >}}[Forward all information in `X-Forwarded-*` headers] section.
+NOTE: The configuration used in the example below requires proper configuration of `trusted_proxies` on heimdall side.
 
-NOTE: The configuration used in the example below requires proper configuration of `trusted_proxies` on heimdall side. On NGINX Ingress Controller side you must allow the usage of `nginx.ingress.kubernetes.io/auth-snippet` (See also https://kubernetes.github.io/ingress-nginx/user-guide/nginx-configuration/configmap/#allow-snippet-annotations[here]).
+Global configuration can be achieved by setting the following properties in controller `ConfigMap`. If you install the NGINX controller via the helm chart, you can add these properties under the `controller.config` property of your helm `values.yaml` file.
 
 [source, yaml]
 ----
-nginx.ingress.kubernetes.io/auth-url: "http://<heimdall service name>.<namespace>.svc.cluster.local:<decision port>" # <1>
-nginx.ingress.kubernetes.io/auth-response-headers: Authorization # <2>
-nginx.ingress.kubernetes.io/auth-snippet: | # <3>
+global-auth-url: "http://<heimdall service name>.<namespace>.svc.cluster.local:<decision port>" # <1>
+global-auth-response-headers: Authorization # <2>
+global-auth-snippet: | # <3>
   proxy_set_header    X-Forwarded-Method   $request_method;
   proxy_set_header    X-Forwarded-Proto    $scheme;
   proxy_set_header    X-Forwarded-Host     $http_host;
   proxy_set_header    X-Forwarded-Uri      $request_uri;
-# other annotations required
 ----
 <1> Configures the controller to use heimdall's decision service endpoint with `<heimdall service name>`, `<namespace>` and `<decision port>` depending on your configuration.
 <2> Let NGINX forward the `Authorization` header set by heimdall to the upstream service upon successful response. This configuration depends on
@@ -150,7 +149,58 @@ your link:{{< relref "/docs/mechanisms/contextualizers.adoc" >}}[Contextualizers
 +
 NOTE: Without that, heimdall will not be able extracting relevant information from the NGINX request as it does not support NGINX proprietary `X-Original-Method` and `X-Original-Uri` used by it for the same purposes.
 
-=== Alternative Configuration
+With that in place, you can simply use the standard https://kubernetes.io/docs/concepts/services-networking/ingress/[`Ingress`] resource, and the NGINX Ingress Controller will ensure, each request will be analyzed by heimdall first.
+
+This will result in an NGINX configuration corresponding to the integration option, described in the link:{{< relref "#_second_option" >}}[Forward all information in `X-Forwarded-*` headers] section.
+
+==== Alternative Configuration
+
+Alternatively, if you don't want configuring `trusted_proxies` and do not rely on the used HTTP scheme, host and port in your rules, you can also use the `location-snippet` and the `server-snippet` to the `ConfigMap` of the NGINX Ingress Controller with values shown below.
+
+This example is an exact copy of the configuration used in the very first link:{{< relref "#_first_option" >}}[integration option] described above.
+
+[source, yaml]
+----
+location-snippet: |
+  auth_request               /_auth;
+  auth_request_set           $auth_cookie $upstream_http_set_cookie;
+  add_header                 Set-Cookie $auth_cookie;
+  auth_request_set           $auth_header $upstream_http_authorization;
+  proxy_set_header           'Authorization' $auth_header;
+  proxy_set_header Proxy     "";
+server-snippet: |
+  location = /_auth {
+    internal;
+    access_log               off;
+    proxy_method             $request_method;
+    proxy_pass               http://<heimdall service name>.<namespace>.svc.cluster.local:<decision port>$request_uri;
+    proxy_pass_request_body  off;
+    proxy_set_header         Content-Length   "";
+    proxy_set_header         Host $http_host;
+  }
+----
+
+As with the previous integration option, you can add these properties under the `controller.config` property of your helm `values.yaml` file if you install the NGINX Ingress Controller via helm.
+
+=== Integration on `Ingress` Resource Level
+
+==== Using `X-Forwarded-*` headers
+
+One option to integrate heimdall with the NGINX Ingress Controller on the `Ingress` resource level is making use of the `nginx.ingress.kubernetes.io/auth-url`, `nginx.ingress.kubernetes.io/auth-response-headers` and the `nginx.ingress.kubernetes.io/auth-snippet` annotation as shown in the example below. This approach requires proper configuration of `trusted_proxies` on heimdall side. On NGINX Ingress Controller side you must allow the usage of `nginx.ingress.kubernetes.io/auth-snippet` (See also https://kubernetes.github.io/ingress-nginx/user-guide/nginx-configuration/configmap/#allow-snippet-annotations[here]).
+
+[source, yaml]
+----
+nginx.ingress.kubernetes.io/auth-url: "http://<heimdall service name>.<namespace>.svc.cluster.local:<decision port>"
+nginx.ingress.kubernetes.io/auth-response-headers: Authorization
+nginx.ingress.kubernetes.io/auth-snippet: |
+  proxy_set_header    X-Forwarded-Method   $request_method;
+  proxy_set_header    X-Forwarded-Proto    $scheme;
+  proxy_set_header    X-Forwarded-Host     $http_host;
+  proxy_set_header    X-Forwarded-Uri      $request_uri;
+# other annotations required
+----
+
+==== Alternative Configuration
 
 Alternatively, if you don't want configuring `trusted_proxies` and do not rely on the used HTTP scheme, host and port in your rules, you can also use the `nginx.ingress.kubernetes.io/configuration-snippet` and `nginx.ingress.kubernetes.io/server-snippet` annotations and use the configuration shown below.
 

examples/kubernetes/Justfile

@@ -93,11 +93,15 @@ install-heimdall-pod-monitor:
 
 install-observability-stack: install-grafana install-prometheus install-loki install-tempo install-phlare install-dashboards install-heimdall-pod-monitor
 
-install-nginx-ingress-controller:
+install-nginx-ingress-controller global_ext_auth="true":
+  #!/usr/bin/env bash
+
+  valuesFile=$({{global_ext_auth}} && echo global-helm-values.yaml || echo helm-values.yaml)
+
   helm upgrade --install ingress-nginx ingress-nginx/ingress-nginx \
     -n nginx-controller --create-namespace \
     --version {{nginx_version}} \
-    --set controller.allowSnippetAnnotations=true \
+    -f nginx/${valuesFile} \
     --wait
 
 install-contour-ingress-controller:
@@ -222,7 +226,9 @@ create-cluster:
 
 setup-cluster: create-cluster setup-charts install-lb install-cert-manager
 
-install-ngnix-decision-demo: setup-cluster install-nginx-ingress-controller (install-heimdall "nginx") (install-echo-service "nginx")
+install-ngnix-decision-demo: setup-cluster (install-nginx-ingress-controller "false") (install-heimdall "nginx") (install-echo-service "nginx-route-based")
+
+install-ngnix-global-decision-demo: setup-cluster install-nginx-ingress-controller (install-heimdall "nginx") (install-echo-service "nginx-global")
 
 install-contour-decision-demo: setup-cluster install-contour-ingress-controller (install-heimdall "contour") (install-echo-service "contour")
 

examples/kubernetes/nginx/global-helm-values.yaml

@@ -0,0 +1,9 @@
+controller:
+  config:
+    global-auth-url: https://heimdall.heimdall.svc.cluster.local:4456
+    global-auth-response-headers: "Authorization"
+    global-auth-snippet: |
+      proxy_set_header         X-Forwarded-Method     $request_method;
+      proxy_set_header         X-Forwarded-Proto      $scheme;
+      proxy_set_header         X-Forwarded-Host       $http_host;
+      proxy_set_header         X-Forwarded-Uri        $request_uri;

examples/kubernetes/nginx/helm-values.yaml

@@ -0,0 +1,2 @@
+controller:
+  allowSnippetAnnotations: true

examples/kubernetes/quickstarts/demo-app/overlays/nginx-global/ingress.yaml

@@ -0,0 +1,24 @@
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: echo-app
+  namespace: quickstarts
+  labels:
+    app.kubernetes.io/name: echo-app
+spec:
+  ingressClassName: "nginx"
+  tls:
+    - hosts:
+        - echo-app.local
+      secretName: echo-app
+  rules:
+    - host: echo-app.local
+      http:
+        paths:
+          - path: /
+            pathType: ImplementationSpecific
+            backend:
+              service:
+                name: echo-app
+                port:
+                  number: 8080

examples/kubernetes/quickstarts/demo-app/overlays/nginx-route-based/kustomization.yaml

@@ -0,0 +1,5 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+resources:
+  - ../../base
+  - ingress.yaml