docs: Updating kubernetes secrets readme

Signed-off-by: Lucas Fontes <lucas@cosmonic.com>

secrets/secrets-kubernetes/README.md

@@ -0,0 +1,152 @@
+# Kubernetes Secrets Backend Implementation for [wasmCloud Secrets](https://github.com/wasmCloud/wasmCloud/issues/2190)
+
+## Basic Usage
+
+Get secret `app-secrets` in the `default` namespace, and expose secret key `some-password` as `some_password` to component.
+
+```yaml
+spec:
+  policies:
+    - name: rust-hello-world-secrets-default
+      type: policy.secret.wasmcloud.dev/v1alpha1
+      properties:
+        backend: kube
+  components:
+    - name: http-component
+      type: component
+      properties:
+        image: .......
+        secrets:
+          - name: some_password
+            properties:
+              policy: rust-hello-world-secrets-default
+              key: app-secrets
+              field: some-password
+```
+
+## Advanced Usage ( Impersonation )
+
+Get secret `cluster-secrets` in the `kube-system` namespace, and expose secret key `tls.crt` as `cluster_certificate` to component.
+The backend will impersonate the `wasmcloud-secrets-privileged` ClusterRole, defined in `impersonate`.
+
+```yaml
+spec:
+  policies:
+    - name: rust-hello-world-secrets-impersonation
+      type: policy.secret.wasmcloud.dev/v1alpha1
+      properties:
+        backend: kube
+        # Cluster Role to Impersonate
+        impersonate: wasmcloud-secrets-privileged
+        # Namespace to retrieve secrets from
+        namespace: kube-system
+  components:
+    - name: http-component
+      type: component
+      properties:
+        image: ...
+        secrets:
+          - name: cluster_certificate
+            properties:
+              policy: rust-hello-world-secrets-impersonation
+              key: cluster-secrets
+              field: tls.crt
+```
+
+## Machinery
+
+- wasmCloud Secrets Protocol ( `server_xkey` and `get` operations )
+- wasCap jwt validation using Ed25519
+- wasCap Host & Entity Capabilities unwrapping
+
+The `pkg/secrets` can be used to implement other Secrets Backends via `secrets.NewServer()` and its `secrets.Handler` companion.
+
+```go
+type secretProvider struct{}
+func (s *secretProvider) Get(ctx context.Context, r *secrets.Request) (*secrets.SecretValue, error) {
+return &secrets.SecretValue{
+    StringSecret: "p@$$w0rd",
+    Version:      "latest",
+}, nil
+}
+
+...
+provider := &secretProvider{}
+// create a secrets server with ephemeral curve key
+// can also pass stable key with `secrets.WithKeyPair(nkeys.KeyPair)`
+secretsServer, _ := secrets.NewServer("provider-name", natsConnection, provider, secrets.WithEphemeralKey())
+
+// Start secrets server
+secretsServer.Run()
+
+// Shutdown secrets server
+// Receives a boolean to drain in-flight messages or bail quickly
+secretsServer.Shutdown(true)
+```
+
+## Installation
+
+### Automated
+
+Refer to the [wasmcloud operator helm chart](https://github.com/wasmCloud/wasmcloud-operator).
+
+### Manual
+
+See [deploy/dev](deploy/dev) for a deployment example. You will need:
+
+- NATS URL
+- A NATS Curve Key to encrypt data between secrets backend & wasmcloud hosts
+
+Generate a Curve key, take note of the generated 'Seed':
+
+```bash
+wash keys gen Curve
+```
+
+These values should be passed to the container as:
+
+```yaml
+args:
+  - "--backend-seed=$(BACKEND_SEED)"
+  - "--nats-url=$(NATS_URL)"
+```
+
+Next step is to give permissions to the service account running the secrets backend. Assuming service account `default` and namespace `wasmcloud-secrets`, give permission to read secrets in the `default` namespace:
+
+```yaml
+apiVersion: rbac.authorization.k8s.io/v1
+kind: Role
+metadata:
+  name: wasmcloud-secrets-reader-default
+  namespace: default
+rules:
+  - apiGroups: [""]
+    resources: ["secrets"]
+    verbs: ["get", "watch", "list"]
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: wasmcloud-secrets-reader-default
+  namespace: default
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: Role
+  name: wasmcloud-secrets-reader-default
+subjects:
+  - apiGroup: rbac.authorization.k8s.io
+    kind: User
+    name: "system:serviceaccount:wasmcloud-secrets:default"
+```
+
+## Local Development
+
+Create `deploy/dev/kubernetes-backend.env` using the provided sample (kubernetes-backend.env.sample).
+
+Build Container Image with `make build`
+
+Deploy manifests with `make dev-init`
+
+Iterate deploys with `make dev-deploy`. This will build & restart containers.
+
+See pod logs with `make dev-logs`

secrets/secrets-kubernetes/deploy/base/deployment.yaml

@@ -17,3 +17,17 @@ spec:
         - image: wasmcloud-secrets
           imagePullPolicy: IfNotPresent
           name: wasmcloud-secrets
+          args:
+            - "--backend-seed=$(BACKEND_SEED)"
+            - "--nats-url=$(NATS_URL)"
+          env:
+            - name: BACKEND_SEED
+              valueFrom:
+                secretKeyRef:
+                  name: wasmcloud-secrets
+                  key: BACKEND_SEED
+            - name: NATS_URL
+              valueFrom:
+                secretKeyRef:
+                  name: wasmcloud-secrets
+                  key: NATS_URL

secrets/secrets-kubernetes/deploy/dev/.gitignore

@@ -0,0 +1 @@
+/kubernetes-backend.env

secrets/secrets-kubernetes/deploy/dev/kubernetes-backend.env.sample

@@ -0,0 +1,2 @@
+BACKEND_SEED=SXALRLSKLIW4FKXJHJXNZMB67QAVEPQEOK67OGLAKSNO73IAJMDEADEJVQ
+NATS_URL=nats.default.svc.cluster.local:4222

secrets/secrets-kubernetes/deploy/dev/kustomization.yaml

@@ -8,14 +8,8 @@ images:
     newName: ghcr.io/wasmcloud/contrib/secrets-kubernetes
     newTag: dev
 
-patches:
-  - patch: |-
-      - op: replace
-        path: "/spec/template/spec/containers/0/args"
-        value:
-          - "--backend-seed=SXAD2NAUWO6YNEFMY4FQT7D45VLLWFOZDVHCENMPHCWA6ABBLZ4OBBKGKQ"
-          - "--nats-url=nats.default.svc.cluster.local:4222"
-    target:
-      kind: Deployment
-      namespace: wasmcloud-secrets
-      name: wasmcloud-secrets
+secretGenerator:
+  - name: wasmcloud-secrets
+    namespace: wasmcloud-secrets
+    envs:
+      - kubernetes-backend.env