Add folder UID validation (#1551)

Closes #1543
Using the regex found here: https://github.com/grafana/grafana/blob/main/pkg/util/shortid_generator.go#L33-L35

Author: julienduchesne

internal/resources/grafana/resource_alerting_rule_group.go

@@ -55,10 +55,11 @@ This resource requires Grafana 9.1.0 or later.
 				Description: "The name of the rule group.",
 			},
 			"folder_uid": {
-				Type:        schema.TypeString,
-				Required:    true,
-				ForceNew:    true,
-				Description: "The UID of the folder that the group belongs to.",
+				Type:         schema.TypeString,
+				Required:     true,
+				ForceNew:     true,
+				Description:  "The UID of the folder that the group belongs to.",
+				ValidateFunc: folderUIDValidation,
 			},
 			"interval_seconds": {
 				Type:        schema.TypeInt,

internal/resources/grafana/resource_folder.go

@@ -3,6 +3,7 @@ package grafana
 import (
 	"context"
 	"encoding/json"
+	"regexp"
 	"strconv"
 
 	goapi "github.com/grafana/grafana-openapi-client-go/client"
@@ -13,8 +14,11 @@ import (
 	"github.com/grafana/terraform-provider-grafana/v2/internal/common"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/validation"
 )
 
+var folderUIDValidation = validation.StringMatch(regexp.MustCompile(`^[a-zA-Z0-9\-\_]+$`), "folder UIDs can only be alphanumeric, dashes, or underscores")
+
 func resourceFolder() *common.Resource {
 	schema := &schema.Resource{
 
@@ -34,11 +38,12 @@ func resourceFolder() *common.Resource {
 		Schema: map[string]*schema.Schema{
 			"org_id": orgIDAttribute(),
 			"uid": {
-				Type:        schema.TypeString,
-				Computed:    true,
-				Optional:    true,
-				ForceNew:    true,
-				Description: "Unique identifier.",
+				Type:         schema.TypeString,
+				Computed:     true,
+				Optional:     true,
+				ForceNew:     true,
+				Description:  "Unique identifier.",
+				ValidateFunc: folderUIDValidation,
 			},
 			"title": {
 				Type:        schema.TypeString,

internal/resources/grafana/resource_folder_permission.go

@@ -30,10 +30,11 @@ Manages the entire set of permissions for a folder. Permissions that aren't spec
 
 		Schema: map[string]*schema.Schema{
 			"folder_uid": {
-				Type:        schema.TypeString,
-				Required:    true,
-				ForceNew:    true,
-				Description: "The UID of the folder.",
+				Type:         schema.TypeString,
+				Required:     true,
+				ForceNew:     true,
+				Description:  "The UID of the folder.",
+				ValidateFunc: folderUIDValidation,
 			},
 		},
 	}

internal/resources/grafana/resource_library_panel.go

@@ -73,6 +73,7 @@ Manages Grafana library panels.
 					_, new = SplitOrgResourceID(new)
 					return old == new
 				},
+				ValidateFunc: folderUIDValidation,
 			},
 			"name": {
 				Type:        schema.TypeString,