About Config File

APIs

AILERON Gateway define each features as decoupled resources. Resources are defined with the following 3 attributes. This concept is borrowed from the Kubernetes. See Kubernetes API Concepts and Objects In Kubernetes.

• API Group: The group of apis. e.g. core, app.
• API Version: The version in a api group. e.g. v1, v1alpha1, v1beta1.
• Kind: The name of resources. e.g. Entrypoint, HTTPServer.

In addition to above, the instances af a resources are identified with namespace and name.

• Namespace: Logical group of resource instances.
• Name: Name of a resource instance.

As a result, all resource instances has their unique identifier defined with this.

<API Group>/<API Version>/<Kind>/<Namespace>/<Name>

In the context of AILERON Gateway, the API refers to a kind of resource such as HTTP server or middleware. APIs and operation to them are managed by the AILERON Gateway internally under the architecture.

Configuration format

All resources have the following config structure.

apiVersion:    <string> API group and version.
kind:          <string> API kind name.
metadata:      <object>
    namespace: <string> Namespace name for logical separation of this instances.
    name:      <string> Name of this instance. Unique in namespace.
spec:          <object> API specific configurations.

That means a yaml like below is the basic format to define resources to use.

apiVersion: <API Version>/<API Group>
kind: <Kind>
metadata:
  namespace: <Namespace>
  name: <Name>
spec: {}

Config files should be following format with their appropriate file extension. yaml and json format are supported as the manifest. AILERON Gateway loads the given manifests on start up and create objects.

• .yaml: YAML format config.
• .yml: YAML format config.
• .json: JSON format config.

For example, this yaml define an HTTP server.

apiVersion: core/v1
kind: HTTPServer
spec:
  addr: ":8080"

And it is identical to

apiVersion: core/v1
kind: HTTPServer
metadata:
  namespace: default # "default" is used if omitted.
  name: default      # "default" is used if omitted.
spec:
  addr: ":8080"