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User guide: Open Policy Agent (OPA) Rego policies

Leverage the power of Open Policy Agent (OPA) policies, evaluated against Authorino's Authorization JSON in a built-in runtime compiled together with Authorino; pre-cache policies defined in Rego language inline or fetched from an external policy registry.

Authorino capabilities featured in this guide:

Authorino supports Open Policy Agent policies, either inline defined in Rego language as part of the AuthConfig or fetched from an external endpoint, such as an OPA Policy Registry.

Authorino's built-in OPA module precompiles the policies in reconciliation-time and cache them for fast evaluation in request-time, where they receive the Authorization JSON as input.

Check out as well the user guide about Authentication with API keys.

For further details about Authorino features in general, check the docs.


Requirements

  • Kubernetes server with permissions to install cluster-scoped resources (operator, CRDs and RBAC)

If you do not own a Kubernetes server already and just want to try out the steps in this guide, you can create a local containerized cluster by executing the command below. In this case, the main requirement is having Kind installed, with either Docker or Podman.

kind create cluster --name authorino-tutorial

The next steps walk you through installing Authorino, deploying and configuring a sample service called Talker API to be protected by the authorization service.

Using Kuadrant

If you are a user of Kuadrant and already have your workload cluster configured and sample service application deployed, as well as your Gateway API network resources applied to route traffic to your service, skip straight to step ❺.

At step ❺, instead of creating an AuthConfig custom resource, create a Kuadrant AuthPolicy one. The schema of the AuthConfig's spec matches the one of the AuthPolicy's, except spec.host, which is not available in the Kuadrant AuthPolicy. Host names in a Kuadrant AuthPolicy are inferred automatically from the Kubernetes network object referred in spec.targetRef and route selectors declared in the policy.

For more about using Kuadrant to enforce authorization, check out Kuadrant auth.

❶ Install the Authorino Operator (cluster admin required)

The following command will install the Authorino Operator in the Kubernetes cluster. The operator manages instances of the Authorino authorization service.

curl -sL https://raw.githubusercontent.com/Kuadrant/authorino-operator/main/utils/install.sh | bash -s

❷ Deploy Authorino

The following command will request an instance of Authorino as a separate service1 that watches for AuthConfig resources in the default namespace2, with TLS disabled3.

kubectl apply -f -<<EOF
apiVersion: operator.authorino.kuadrant.io/v1beta1
kind: Authorino
metadata:
  name: authorino
spec:
  listener:
    tls:
      enabled: false
  oidcServer:
    tls:
      enabled: false
EOF

❸ Deploy the Talker API

The Talker API is a simple HTTP service that echoes back in the response whatever it gets in the request. We will use it in this guide as the sample service to be protected by Authorino.

kubectl apply -f https://raw.githubusercontent.com/kuadrant/authorino-examples/main/talker-api/talker-api-deploy.yaml

❹ Setup Envoy

The following bundle from the Authorino examples deploys the Envoy proxy and configuration to wire up the Talker API behind the reverse-proxy, with external authorization enabled with the Authorino instance.4

kubectl apply -f https://raw.githubusercontent.com/kuadrant/authorino-examples/main/envoy/envoy-notls-deploy.yaml

The command above creates an Ingress with host name talker-api.127.0.0.1.nip.io. If you are using a local Kubernetes cluster created with Kind, forward requests from your local port 8000 to the Envoy service running inside the cluster:

kubectl port-forward deployment/envoy 8000:8000 2>&1 >/dev/null &

❺ Create an AuthConfig

Create an Authorino AuthConfig custom resource declaring the auth rules to be enforced.

In this example, we will use OPA to implement a read-only policy for requests coming from outside a trusted network (IP range 192.168.1/24).

The implementation relies on the X-Forwarded-For HTTP header to read the client's IP address.5

Kuadrant users – Remember to create an AuthPolicy instead of an AuthConfig. For more, see Kuadrant auth. 
kubectl apply -f -<<EOF
apiVersion: authorino.kuadrant.io/v1beta3
kind: AuthConfig
metadata:
  name: talker-api-protection
spec:
  hosts:
  - talker-api.127.0.0.1.nip.io
  authentication:
    "friends":
      apiKey:
        selector:
          matchLabels:
            group: friends
      credentials:
        authorizationHeader:
          prefix: APIKEY
  authorization:
    "read-only-outside":
      opa:
        rego: |
          ips := split(input.context.request.http.headers["x-forwarded-for"], ",")
          trusted_network { net.cidr_contains("192.168.1.1/24", ips[0]) }

          allow { trusted_network }
          allow { not trusted_network; input.context.request.http.method == "GET" }
EOF

❻ Create the API key

kubectl apply -f -<<EOF
apiVersion: v1
kind: Secret
metadata:
  name: api-key-1
  labels:
    authorino.kuadrant.io/managed-by: authorino
    group: friends
stringData:
  api_key: ndyBzreUzF4zqDQsqSPMHkRhriEOtcRx
type: Opaque
EOF

❼ Consume the API

Inside the trusted network:

curl -H 'Authorization: APIKEY ndyBzreUzF4zqDQsqSPMHkRhriEOtcRx' \
     -H 'X-Forwarded-For: 192.168.1.10' \
     http://talker-api.127.0.0.1.nip.io:8000/hello
# HTTP/1.1 200 OK
curl -H 'Authorization: APIKEY ndyBzreUzF4zqDQsqSPMHkRhriEOtcRx' \
     -H 'X-Forwarded-For: 192.168.1.10' \
     -X POST \
     http://talker-api.127.0.0.1.nip.io:8000/hello
# HTTP/1.1 200 OK

Outside the trusted network:

curl -H 'Authorization: APIKEY ndyBzreUzF4zqDQsqSPMHkRhriEOtcRx' \
     -H 'X-Forwarded-For: 123.45.6.78' \
     http://talker-api.127.0.0.1.nip.io:8000/hello
# HTTP/1.1 200 OK
curl -H 'Authorization: APIKEY ndyBzreUzF4zqDQsqSPMHkRhriEOtcRx' \
     -H 'X-Forwarded-For: 123.45.6.78' \
     -X POST \
     http://talker-api.127.0.0.1.nip.io:8000/hello -i
# HTTP/1.1 403 Forbidden
# x-ext-auth-reason: Unauthorized

Cleanup

If you have started a Kubernetes cluster locally with Kind to try this user guide, delete it by running:

kind delete cluster --name authorino-tutorial

Otherwise, delete the resources created in each step:

kubectl delete secret/api-key-1
kubectl delete authconfig/talker-api-protection
kubectl delete -f https://raw.githubusercontent.com/kuadrant/authorino-examples/main/envoy/envoy-notls-deploy.yaml
kubectl delete -f https://raw.githubusercontent.com/kuadrant/authorino-examples/main/talker-api/talker-api-deploy.yaml
kubectl delete authorino/authorino

To uninstall the Authorino Operator and manifests (CRDs, RBAC, etc), run:

kubectl delete -f https://raw.githubusercontent.com/Kuadrant/authorino-operator/main/config/deploy/manifests.yaml

Footnotes

  1. In contrast to a dedicated sidecar of the protected service and other architectures. Check out Architecture > Topologies for all options. ↩

  2. namespaced reconciliation mode. See Cluster-wide vs. Namespaced instances. ↩

  3. For other variants and deployment options, check out Getting Started, as well as the Authorino CRD specification. ↩

  4. For details and instructions to setup Envoy manually, see Protect a service > Setup Envoy in the Getting Started page. If you are running your ingress gateway in Kubernetes and wants to avoid setting up and configuring your proxy manually, check out Kuadrant. ↩

  5. You can also set use_remote_address: true in the Envoy route configuration, so the proxy will append its IP address instead of run in transparent mode. This setting will also ensure real remote address of the client connection passed in the x-envoy-external-address HTTP header, which can be used to simplify the read-only policy in remote environment. ↩