Add example 3 and update docs

Author: Tavasya Ganpati

docs/data-sources/diff.md

@@ -0,0 +1,306 @@
+---
+page_title: "helm: helm_diff"
+sidebar_current: "docs-helm-diff"
+description: |-
+
+---
+# Data Source: helm_diff
+
+Compare a proposed Helm chart configuration against a deployed release.
+
+`helm_diff` compares a proposed chart configuration against what is currently deployed in the Kubernetes cluster and outputs the differences. This is useful for drift detection, change preview before upgrades, and CI/CD integration.
+
+<!-- schema generated by tfplugindocs -->
+## Schema
+
+### Required
+
+- `chart` (String) Chart name to be installed. A path may be used.
+- `name` (String) Release name
+
+### Optional
+
+- `api_versions` (List of String) Kubernetes api versions used for Capabilities.APIVersions.
+- `create_namespace` (Boolean) Create the namespace if it does not exist.
+- `dependency_update` (Boolean) Run helm dependency update before installing the chart.
+- `description` (String) Add a custom description.
+- `devel` (Boolean) Use chart development versions, too. Equivalent to version '>0.0.0-0'. If `version` is set, this is ignored.
+- `disable_openapi_validation` (Boolean) If set, the installation process will not validate rendered templates against the Kubernetes OpenAPI Schema.
+- `disable_webhooks` (Boolean) Prevent hooks from running.
+- `include_crds` (Boolean) Include CRDs in the templated output.
+- `keyring` (String) Location of public keys used for verification. Used only if `verify` is true.
+- `kube_version` (String) Kubernetes version used for Capabilities.KubeVersion.
+- `namespace` (String) Namespace to install the release into.
+- `pass_credentials` (Boolean) Pass credentials to all domains
+- `postrender` (Attributes) Postrender command config (see [below for nested schema](#nestedatt--postrender))
+- `render_subchart_notes` (Boolean) If set, render subchart notes along with the parent.
+- `repository` (String) Repository where to locate the requested chart. If it is a URL the chart is installed without installing the repository.
+- `repository_ca_file` (String) The repository's CA file
+- `repository_cert_file` (String) The repository's cert file
+- `repository_key_file` (String) The repository's cert key file
+- `repository_password` (String, Sensitive) Password for HTTP basic authentication
+- `repository_username` (String) Username for HTTP basic authentication
+- `set` (Attributes Set) Custom values to be merged with the values (see [below for nested schema](#nestedatt--set))
+- `set_list` (Attributes List) Custom sensitive values to be merged with the values (see [below for nested schema](#nestedatt--set_list))
+- `set_sensitive` (Attributes Set) Custom sensitive values to be merged with the values (see [below for nested schema](#nestedatt--set_sensitive))
+- `set_wo` (Attributes List) Write-only custom values to be merged with the values. (see [below for nested schema](#nestedatt--set_wo))
+- `skip_crds` (Boolean) If set, no CRDs will be installed. By default, CRDs are installed if not already present.
+- `timeout` (Number) Time in seconds to wait for any individual Kubernetes operation.
+- `timeouts` (Attributes) (see [below for nested schema](#nestedatt--timeouts))
+- `validate` (Boolean) Validate your manifests against the Kubernetes cluster you are currently pointing at. This is the same validation performed on an install.
+- `values` (List of String) List of values in raw yaml format to pass to helm.
+- `verify` (Boolean) Verify the package before installing it.
+- `version` (String) Specify the exact chart version to install. If this is not specified, the latest version is installed.
+
+### Read-Only
+
+- `current_manifest` (String) Currently deployed manifest
+- `diff` (String) Unified diff output
+- `diff_json` (String) Structured JSON diff
+- `has_changes` (Boolean) Whether any changes were detected
+- `id` (String) The ID of this resource.
+- `proposed_manifest` (String) Proposed manifest
+
+<a id="nestedatt--postrender"></a>
+### Nested Schema for `postrender`
+
+Required:
+
+- `binary_path` (String) The common binary path
+
+Optional:
+
+- `args` (List of String) An argument to the post-renderer (can specify multiple)
+
+
+<a id="nestedatt--set"></a>
+### Nested Schema for `set`
+
+Required:
+
+- `name` (String)
+
+Optional:
+
+- `type` (String)
+- `value` (String)
+
+
+<a id="nestedatt--set_list"></a>
+### Nested Schema for `set_list`
+
+Required:
+
+- `value` (List of String)
+
+Optional:
+
+- `name` (String)
+
+
+<a id="nestedatt--set_sensitive"></a>
+### Nested Schema for `set_sensitive`
+
+Required:
+
+- `name` (String)
+- `value` (String, Sensitive)
+
+Optional:
+
+- `type` (String)
+
+
+<a id="nestedatt--set_wo"></a>
+### Nested Schema for `set_wo`
+
+Required:
+
+- `name` (String)
+- `value` (String)
+
+Optional:
+
+- `type` (String)
+
+
+<a id="nestedatt--timeouts"></a>
+### Nested Schema for `timeouts`
+
+Optional:
+
+- `read` (String) A string that can be [parsed as a duration](https://pkg.go.dev/time#ParseDuration) consisting of numbers and unit suffixes, such as "30s" or "2h45m". Valid time units are "s" (seconds), "m" (minutes), "h" (hours).
+
+
+
+
+## Example Usage
+
+### Check what would be created for a new release
+
+The following example shows using `helm_diff` to preview what resources would be created when deploying a new release that doesn't exist yet.
+
+```terraform
+# Deploy initial release with specific configuration
+resource "helm_release" "mariadb" {
+  name       = "mariadb-instance"
+  namespace  = "default"
+  repository = "https://charts.helm.sh/stable"
+
+  chart   = "mariadb"
+  version = "7.1.0"
+
+  set {
+    name  = "service.port"
+    value = "13306"
+  }
+
+  set {
+    name  = "replication.enabled"
+    value = "false"
+  }
+}
+
+# Check what would change if we modify the configuration
+data "helm_diff" "mariadb_upgrade" {
+  name       = "mariadb-instance"
+  namespace  = "default"
+  repository = "https://charts.helm.sh/stable"
+
+  chart   = "mariadb"
+  version = "7.1.0"  # Same version
+
+  set = [
+    {
+      name  = "service.port"
+      value = "3306" 
+    },
+    {
+      name  = "replication.enabled"
+      value = "true"
+    }
+  ]
+
+  depends_on = [helm_release.mariadb]
+}
+
+output "has_changes" {
+  description = "Whether the proposed config differs from deployed"
+  value       = data.helm_diff.mariadb_upgrade.has_changes
+}
+
+output "what_will_change" {
+  description = "Detailed diff of configuration changes"
+  value       = data.helm_diff.mariadb_upgrade.diff
+}
+
+output "changes_json" {
+  description = "JSON structure showing modified resources"
+  value       = data.helm_diff.mariadb_upgrade.diff_json
+}
+```
+
+### Verify deployed release matches desired configuration
+
+The following example shows using `helm_diff` to verify that a deployed release matches your desired configuration (drift detection).
+
+```terraform
+data "helm_diff" "mariadb_instance" {
+  name       = "mariadb-instance"
+  namespace  = "default"
+  repository = "https://charts.helm.sh/stable"
+
+  chart   = "mariadb"
+  version = "7.1.0"
+
+  set = [
+    {
+      name  = "service.port"
+      value = "13306"
+    }
+  ]
+
+  set_sensitive = [
+    {
+      name  = "rootUser.password"
+      value = "s3cr3t!"
+    }
+  ]
+}
+
+
+output "has_changes" {
+  value = data.helm_diff.mariadb_instance.has_changes
+}
+
+output "diff_output" {
+  value = data.helm_diff.mariadb_instance.diff
+}
+
+output "current_manifest" {
+  value = data.helm_diff.mariadb_instance.current_manifest
+}
+
+output "proposed_manifest" {
+  value = data.helm_diff.mariadb_instance.proposed_manifest
+}
+```
+
+### Preview configuration changes before applying
+
+The following example shows using `helm_diff` to preview what would change if you modify the configuration of an existing release.
+
+```terraform
+resource "helm_release" "mariadb" {
+  name       = "mariadb-instance"
+  namespace  = "default"
+  repository = "https://charts.helm.sh/stable"
+
+  chart   = "mariadb"
+  version = "7.1.0"
+
+  set {
+    name  = "service.port"
+    value = "13306"
+  }
+
+  set {
+    name  = "replication.enabled"
+    value = "false"
+  }
+}
+
+data "helm_diff" "mariadb_upgrade" {
+  name       = "mariadb-instance"
+  namespace  = "default"
+  repository = "https://charts.helm.sh/stable"
+
+  chart   = "mariadb"
+  version = "7.1.0"
+
+  set = [
+    {
+      name  = "service.port"
+      value = "3306"  
+    },
+    {
+      name  = "replication.enabled"
+      value = "true"
+    }
+  ]
+
+  depends_on = [helm_release.mariadb]
+}
+
+output "has_changes" {
+  value       = data.helm_diff.mariadb_upgrade.has_changes
+}
+
+output "what_will_change" {
+  value       = data.helm_diff.mariadb_upgrade.diff
+}
+
+output "changes_json" {
+  value       = data.helm_diff.mariadb_upgrade.diff_json
+}
+```