Can someone explain this K8s ingress file

Question

I have encountered this ingress file and struggling to understand http (& , *) meaning in this ingress file- Can some one please explain * and & meaning here?

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  annotations:
    cert-manager.io/cluster-issuer: letsencrypt
  name: my-example
spec:
  rules:
  - host: example.com
    http: &exampleBackendService
      paths:
      - backend:
          serviceName: my-example
          servicePort: 80
        path: /
  - host: example-dev.com
    http: *exampleBackendService

Answer 1

It's all yaml grammer, nothing with k8s. see Anchors and Aliases, or a simpler tutorial.
The purpose is reuse, shorter and maintainability.

You can use python(among many choices) to expand:

import yaml


class ExplicitDumper(yaml.SafeDumper):
    def ignore_aliases(self, data):
        return True


d = yaml.safe_load('''your very long yaml string''')
print(yaml.dump(d, Dumper=ExplicitDumper))

output

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  annotations:
    cert-manager.io/cluster-issuer: letsencrypt
  name: my-example
spec:
  rules:
  - host: example.com
    http:
      paths:
      - backend:
          serviceName: my-example
          servicePort: 80
        path: /
  - host: example-dev.com
    http:
      paths:
      - backend:
          serviceName: my-example
          servicePort: 80
        path: /