This tutorial shows how to expose service endpoints in multiple Namespaces using API Gateway Controller.

CAUTION: Exposing a workload to the outside world causes a potential security vulnerability, so tread carefully. In a production environment, secure the workload you expose with OAuth2 or JWT.

Prerequisites

1. Create three Namespaces: one for an instance of the HttpBin service, one for a sample Function, and one for an APIRule custom resource (CR). Deploy an instance of the HttpBin service and a sample Function in their respective Namespaces. To learn how to do it, follow the Create a workload tutorial.

   NOTE: Remember to enable the Istio sidecar proxy injection in each Namespace.

2. Export the Namespaces' names as environment variables:

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   export NAMESPACE_HTTPBIN={NAMESPACE_NAME}
   export NAMESPACE_FUNCTION={NAMESPACE_NAME}
   export NAMESPACE_APIRULE={NAMESPACE_NAME}

3. Depending on whether you use your custom domain or a Kyma domain, export the necessary values as environment variables:

export DOMAIN_TO_EXPOSE_WORKLOADS={DOMAIN_NAME}
export GATEWAY=$NAMESPACE_APIRULE/httpbin-gateway

Expose and access your workloads in multiple Namespaces

1. Expose the HttpBin and Function services in their respective Namespaces by creating an APIRule CR in its own Namespace. Run:

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   cat <<EOF | kubectl apply -f -
   apiVersion: gateway.kyma-project.io/v1beta1
   kind: APIRule
   metadata:
     name: httpbin-and-function
     namespace: $NAMESPACE_APIRULE
   spec:
     host: httpbin-and-function.$DOMAIN_TO_EXPOSE_WORKLOADS
     gateway: $GATEWAY
     rules:
       - path: /headers
         methods: ["GET"]
         service:
           name: httpbin
           namespace: $NAMESPACE_HTTPBIN
           port: 8000
         accessStrategies:
           - handler: noop
         mutators:
           - handler: noop
       - path: /function
         methods: ["GET"]
         service:
           name: function
           namespace: $NAMESPACE_FUNCTION
           port: 80
         accessStrategies:
           - handler: noop
         mutators:
           - handler: noop
   EOF

   NOTE: If you are running Kyma on k3d, add httpbin.kyma.local to the entry with k3d IP in your system's /etc/hosts file.

2. Call the HttpBin endpoint by sending a GET request to the HttpBin service:

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   curl -ik -X GET https://httpbin-and-function.$DOMAIN_TO_EXPOSE_WORKLOADS/headers

   If successful, the call returns the code 200 OK response.

3. Call the Function endpoint by sending a GET request to the Function service:

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   curl -ik -X GET https://httpbin-and-function.$DOMAIN_TO_EXPOSE_WORKLOADS/function

   If successful, the call returns the code 200 OK response.