fix(rdb): check user exist (#1720)

Co-authored-by: Rémy Léone <[email protected]>

Author: Monitob

docs/resources/rdb_user.md

@@ -21,7 +21,7 @@ resource "random_password" "db_password" {
 
 resource "scaleway_rdb_user" "db_admin" {
   instance_id = scaleway_rdb_instance.main.id
-  name        = "titi"
+  name        = "devtools"
   password    = random_password.db_password.result
   is_admin    = true
 }

scaleway/resource_rdb_user.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"strings"
 
+	"github.com/hashicorp/terraform-plugin-log/tflog"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
@@ -137,6 +138,11 @@ func resourceScalewayRdbUserRead(ctx context.Context, d *schema.ResourceData, me
 		}
 		return diag.FromErr(err)
 	}
+	if len(res.Users) == 0 {
+		tflog.Warn(ctx, fmt.Sprintf("couldn'd find user with name: [%s]", userName))
+		d.SetId("")
+		return nil
+	}
 
 	user := res.Users[0]
 	_ = d.Set("instance_id", newRegionalID(region, instanceID).String())