Enable configuring the Shim via the spin-operator

Users should be able to set Pod environment variables via the SpinApp CRD. These can be used for configuring settings, such as open telemetry endpoints:

env:
 - name: NODE_IP
    valueFrom:
      fieldRef:
        fieldPath: status.hostIP
 - name: OTEL_EXPORTER_OTLP_ENDPOINT
    value: "http://$(NODE_IP):4318"

Proposal: add a SpinApp.spec.env

Workaround

Create deployment directly instead of creating a SpinApp CR, bypassing the Spin operator:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: spin-test
spec:
  replicas: 1
  selector:
    matchLabels:
      app: spin-test
  template:
    metadata:
      labels:
        app: spin-test
    spec:
      runtimeClassName: wasmtime-spin-v2
      containers:
      - name: spin-test
        image: ttl.sh/spin-foo-123:48h
        command: ["/"]
        ports:
        - containerPort: 80
        env:
       - name: NODE_IP
          valueFrom:
            fieldRef:
              fieldPath: status.hostIP
         - name: OTEL_EXPORTER_OTLP_ENDPOINT
            value: "http://$(NODE_IP):4318"

Begin with the SpinApp CRD definition and the operator's generated Deployment, then trace how pod environment is currently configured. Implement the proposed spec.env field and confirm that the resulting Deployment preserves value and valueFrom entries, including the NODE_IP and OTEL example.