add lua script doc (#468)

Author: zreigz

generated/routes.json

@@ -13,7 +13,7 @@
   },
   "/overview/management-api-reference": {
     "relPath": "/overview/management-api-reference.md",
-    "lastmod": "2025-05-16T13:24:36.000Z"
+    "lastmod": "2025-06-06T08:44:49.000Z"
   },
   "/overview/agent-api-reference": {
     "relPath": "/overview/agent-api-reference.md",
@@ -115,6 +115,10 @@
     "relPath": "/plural-features/continuous-deployment/helm-service.md",
     "lastmod": "2025-03-12T14:59:41.000Z"
   },
+  "/plural-features/continuous-deployment/lua": {
+    "relPath": "/plural-features/continuous-deployment/lua.md",
+    "lastmod": "2025-06-09T12:07:35.725Z"
+  },
   "/plural-features/continuous-deployment/global-service": {
     "relPath": "/plural-features/continuous-deployment/global-service.md",
     "lastmod": "2025-03-12T14:59:41.000Z"
@@ -273,7 +277,7 @@
   },
   "/plural-features/pr-automation/crds": {
     "relPath": "/plural-features/pr-automation/crds.md",
-    "lastmod": "2025-05-19T07:10:18.000Z"
+    "lastmod": "2025-06-05T13:01:10.000Z"
   },
   "/plural-features/pr-automation/testing": {
     "relPath": "/plural-features/pr-automation/testing.md",
@@ -293,7 +297,7 @@
   },
   "/plural-features/service-templating/supporting-liquid-filters": {
     "relPath": "/plural-features/service-templating/supporting-liquid-filters.md",
-    "lastmod": "2025-03-12T14:59:41.000Z"
+    "lastmod": "2025-06-06T08:44:49.000Z"
   },
   "/plural-features/projects-and-multi-tenancy": {
     "relPath": "/plural-features/projects-and-multi-tenancy/index.md",
@@ -533,7 +537,7 @@
   },
   "/deployments/pr/crds": {
     "relPath": "/plural-features/pr-automation/crds.md",
-    "lastmod": "2025-05-19T07:10:18.000Z"
+    "lastmod": "2025-06-05T13:01:10.000Z"
   },
   "/deployments/pr/testing": {
     "relPath": "/plural-features/pr-automation/testing.md",

pages/plural-features/continuous-deployment/helm-service.md

@@ -3,7 +3,10 @@ title: Helm-sourced services
 description: Source manifests from a helm repository registered anywhere
 ---
 
-You can also source manifests from a https or OCI-compatible helm repository. This is very useful for provisioning kubernetes add-ons, which are usually packaged using helm, or occasionally for complex release processes where helms versioning independent of git can be valuable. The path here requires creation of a Flux `HelmRepository` CR first, then the service, e.g.:
+You can also source manifests from a https or OCI-compatible helm repository. This is very useful for provisioning
+kubernetes add-ons, which are usually packaged using helm, or occasionally for complex release processes where helms
+versioning independent of git can be valuable. The path here requires creation of a Flux `HelmRepository` CR first, then
+the service, e.g.:
 
 ```yaml
 # the Cluster resource should ideally be defined in separate files in your infra repo
@@ -44,6 +47,44 @@ spec:
     namespace: infra
 ```
 
+## Dynamic Helm Configuration via luaScript
+
+Plural supports runtime configuration generation via Lua scripting. This feature allows Helm deployments to
+dynamically compute `values` and `valuesFiles`, enabling powerful CI/CD workflows and context-aware configuration.
+
+```yaml
+apiVersion: deployments.plural.sh/v1alpha1
+kind: ServiceDeployment
+metadata:
+  name: nginx
+  namespace: infra
+spec:
+  namespace: ingress-nginx
+  name: ingress-nginx
+  helm:
+    version: 4.4.x
+    chart: ingress-nginx
+    url: https://kubernetes.github.io/ingress-nginx
+    luaScript: |
+      -- Lua code returning:
+      -- { values: table<string, any>, valuesFiles: list<string> }
+      values = {}
+      values["appName"] = "MyApplication"
+      values["version"] = "1.2.3"
+      values["debug"] = true
+      values["maxConnections"] = 100
+
+      valuesFiles = {"config.json", "secrets.yaml"}
+    repository:
+      namespace: infra
+      name: nginx # referenced helm repository above
+  clusterRef:
+    kind: Cluster
+    name: k3s
+    namespace: infra
+```
+For more information, see [Dynamic Helm Configuration with Lua Scripts](lua.md).
+
 ## Multi-Source Helm
 
 Say you want to source the helm templates from an upstream helm repository, but the values files from a Git repository.  In that case, you can define a multi-sourced service, which has both a git and helm repository defined.  It would look like so: