fix: adjust doc and code to support sku free tier is no longer available

internal/services/loganalytics/log_analytics_workspace_resource.go

@@ -21,6 +21,7 @@ import (
 	"github.com/hashicorp/terraform-provider-azurerm/helpers/azure"
 	"github.com/hashicorp/terraform-provider-azurerm/helpers/tf"
 	"github.com/hashicorp/terraform-provider-azurerm/internal/clients"
+	"github.com/hashicorp/terraform-provider-azurerm/internal/features"
 	"github.com/hashicorp/terraform-provider-azurerm/internal/services/loganalytics/migration"
 	"github.com/hashicorp/terraform-provider-azurerm/internal/services/loganalytics/validate"
 	"github.com/hashicorp/terraform-provider-azurerm/internal/tags"
@@ -31,7 +32,7 @@ import (
 )
 
 func resourceLogAnalyticsWorkspace() *pluginsdk.Resource {
-	return &pluginsdk.Resource{
+	schema := &pluginsdk.Resource{
 		Create: resourceLogAnalyticsWorkspaceCreateUpdate,
 		Read:   resourceLogAnalyticsWorkspaceRead,
 		Update: resourceLogAnalyticsWorkspaceCreateUpdate,
@@ -107,7 +108,6 @@ func resourceLogAnalyticsWorkspace() *pluginsdk.Resource {
 				Optional: true,
 				Computed: true,
 				ValidateFunc: validation.StringInSlice([]string{
-					string(workspaces.WorkspaceSkuNameEnumFree),
 					string(workspaces.WorkspaceSkuNameEnumPerGBTwoZeroOneEight),
 					string(workspaces.WorkspaceSkuNameEnumPerNode),
 					string(workspaces.WorkspaceSkuNameEnumPremium),
@@ -179,6 +179,21 @@ func resourceLogAnalyticsWorkspace() *pluginsdk.Resource {
 			"tags": commonschema.Tags(),
 		},
 	}
+
+	if !features.FourPointOh() {
+		schema.Schema["sku"].ValidateFunc = validation.StringInSlice([]string{
+			string(workspaces.WorkspaceSkuNameEnumFree),
+			string(workspaces.WorkspaceSkuNameEnumPerGBTwoZeroOneEight),
+			string(workspaces.WorkspaceSkuNameEnumPerNode),
+			string(workspaces.WorkspaceSkuNameEnumPremium),
+			string(workspaces.WorkspaceSkuNameEnumStandalone),
+			string(workspaces.WorkspaceSkuNameEnumStandard),
+			string(workspaces.WorkspaceSkuNameEnumCapacityReservation),
+			"Unlimited", // TODO check if this is actually no longer valid, removed in v28.0.0 of the SDK
+		}, false)
+	}
+
+	return schema
 }
 
 func resourceLogAnalyticsWorkspaceCustomDiff(ctx context.Context, d *pluginsdk.ResourceDiff, _ interface{}) error {

website/docs/r/log_analytics_workspace.html.markdown

@@ -41,14 +41,12 @@ The following arguments are supported:
 
 * `local_authentication_disabled` - (Optional) Specifies if the log Analytics workspace should enforce authentication using Azure AD. Defaults to `false`.
 
-* `sku` - (Optional) Specifies the SKU of the Log Analytics Workspace. Possible values are `Free`, `PerNode`, `Premium`, `Standard`, `Standalone`, `Unlimited`, `CapacityReservation`, and `PerGB2018` (new SKU as of `2018-04-03`). Defaults to `PerGB2018`.
+* `sku` - (Optional) Specifies the SKU of the Log Analytics Workspace. Possible values are `PerNode`, `Premium`, `Standard`, `Standalone`, `Unlimited`, `CapacityReservation`, and `PerGB2018` (new SKU as of `2018-04-03`). Defaults to `PerGB2018`.
 
 ~> **NOTE:** A new pricing model took effect on `2018-04-03`, which requires the SKU `PerGB2018`. If you're provisioned resources before this date you have the option of remaining with the previous Pricing SKU and using the other SKUs defined above. More information about [the Pricing SKUs is available at the following URI](https://aka.ms/PricingTierWarning).
 
 ~> **NOTE:** Changing `sku` forces a new Log Analytics Workspace to be created, except when changing between `PerGB2018` and `CapacityReservation`. However, changing `sku` to `CapacityReservation` or changing `reservation_capacity_in_gb_per_day` to a higher tier will lead to a 31-days commitment period, during which the SKU cannot be changed to a lower one. Please refer to [official documentation](https://learn.microsoft.com/en-us/azure/azure-monitor/logs/cost-logs#commitment-tiers) for further information.
 
-~> **NOTE:** The `Free` SKU has a default `daily_quota_gb` value of `0.5` (GB).
-
 * `retention_in_days` - (Optional) The workspace data retention in days. Possible values are either 7 (Free Tier only) or range between 30 and 730.
 
 * `daily_quota_gb` - (Optional) The workspace daily quota for ingestion in GB. Defaults to -1 (unlimited) if omitted.