Fix 101-synapse (#187)

* fix 101-synapse

Co-authored-by: zjhe <hezijie@microsoft.com>

quickstart/101-synapse/synapse_workspace.tf

@@ -1,3 +1,17 @@
+resource "random_password" "password" {
+  count = var.synadmin_password == null ? 1 : 0
+
+  length      = 20
+  min_lower   = 1
+  min_upper   = 1
+  min_numeric = 1
+  min_special = 1
+}
+
+locals {
+  synadmin_password = try(random_password.password[0].result, var.synadmin_password)
+}
+
 resource "azurerm_synapse_workspace" "default" {
   name                                 = "syn-${local.basename}"
   resource_group_name                  = azurerm_resource_group.default.name
@@ -5,14 +19,18 @@ resource "azurerm_synapse_workspace" "default" {
   storage_data_lake_gen2_filesystem_id = azurerm_storage_data_lake_gen2_filesystem.default.id
 
   sql_administrator_login          = var.synadmin_username
-  sql_administrator_login_password = var.synadmin_password
+  sql_administrator_login_password = local.synadmin_password
 
   managed_resource_group_name = "${azurerm_resource_group.default.name}-syn-managed"
 
-  aad_admin {
-    login     = var.aad_login.name
-    object_id = var.aad_login.object_id
-    tenant_id = var.aad_login.tenant_id
+  dynamic "aad_admin" {
+    for_each = var.aad_login == null ? [] : ["aad_admin"]
+
+    content {
+      login     = var.aad_login.name
+      object_id = var.aad_login.object_id
+      tenant_id = var.aad_login.tenant_id
+    }
   }
 
   identity {