Add basic observability example to classic dataset (#3697)

* Add basic observability example to classic dataset

* Add boilerplate and observability schema

* Lint fix

* Add observability schema to project-factory module

* Extend duplicate-diff

* Fix tests

* Remove unused schemas

modules/project/alerts.tf

@@ -135,7 +135,7 @@ resource "google_monitoring_alert_policy" "alerts" {
       # first try to get a channel created by this module
       google_monitoring_notification_channel.channels[x].name,
       # otherwise check the context
-      var.context.notification_channels[x],
+      local.ctx.notification_channels[x],
       # if nothing else, use the provided channel as is
       x
     )

modules/project/logging-metrics.tf

@@ -1,5 +1,5 @@
 /**
- * Copyright 2025 Google LLC
+ * Copyright 2026 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -71,7 +71,7 @@ resource "google_logging_metric" "metrics" {
   disabled    = each.value.disabled
   bucket_name = try(
     # first try to check the context
-    var.context.log_buckets[each.value.bucket_name],
+    local.ctx.log_buckets[each.value.bucket_name],
     # if nothing else, use the provided channel as is
     each.value.bucket_name
   )

modules/project/notification-channels.tf

@@ -1,5 +1,5 @@
 /**
- * Copyright 2025 Google LLC
+ * Copyright 2026 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -45,8 +45,16 @@ resource "google_monitoring_notification_channel" "channels" {
   description  = each.value.description
   display_name = each.value.display_name
   enabled      = each.value.enabled
-  labels       = each.value.labels
-  user_labels  = each.value.user_labels
+  labels = each.value.labels == null ? null : {
+    for k, v in each.value.labels :
+    # allow interpolation of email addresses and pubsub topics
+    k => try(
+      local.ctx.email_addresses[v],
+      local.ctx.pubsub_topics[v],
+      v
+    )
+  }
+  user_labels = each.value.user_labels
   dynamic "sensitive_labels" {
     for_each = each.value.sensitive_labels[*]
     content {