Terraform GCPt: Value does not match the regular expression in topic name

Question

I create a notification channel for my alerts:

resource "google_monitoring_notification_channel" "slack_notification_channel" {
  display_name = "${var.project_name_prefix}-notification-channel"
  type         = "pubsub"
  labels = {
    topic = "${var.pubsub_topic_name}"
  }
}

Public and subscriber:

resource "google_pubsub_topic" "pubsub_topic" {
  name = "${var.pubsub_topic_name}"
}

resource "google_pubsub_subscription" "pubsub_subscription" {
  name  = "${var.project_name_prefix}-subscription"
  topic = "${var.pubsub_topic_name}"

  ack_deadline_seconds = 10

  push_config {
    push_endpoint = "${var.push_endpoint_link}"

    attributes = {
      x-goog-version = "v1"
    }
  }
}

Name of the topic: "develop-alerts-topic". Problem with terraform output (In manual I create topic easy):

googleapi: Error 400: Field notification_channel.labels[topic] had an invalid value of "develop-alerts-topic": Value does not match the regular expression "projects/[^/]+/topics/[^/]+".

Could you please help me understand the problem why I get an error (but all elements created)??

Answer 1

You have to reuse your topic definition

resource "google_pubsub_topic" "pubsub_topic" {
  name = "${var.pubsub_topic_name}"
}

In your subscription defintition, like this

resource "google_pubsub_subscription" "pubsub_subscription" {
  name  = "${var.project_name_prefix}-subscription"
  # Reuse the definition of your topic. and get the name
  topic = google_pubsub_topic.pubsub_topic.name

  ack_deadline_seconds = 10

  push_config {
    push_endpoint = "${var.push_endpoint_link}"

    attributes = {
      x-goog-version = "v1"
    }
  }
}

You have an example in the documentation