Terraform Datadog Query Is Invalid

I'm trying to test out creating a monitor for google pub sub and am getting an "Invalid Query" error. This is the query text when i view source of another working monitor, so i'm confused as to why this isn't working.

Error: Error: error creating monitor: 400 Bad Request: {"errors":["The value provided for parameter 'query' is invalid"]}

Terraform:

resource "datadog_monitor" "bad_stuff_sub_monitor" {
  name               = "${var.customer_name} Bad Stuff Monitor"
  type               = "metric alert"
  message            = "${var.customer_name} Bad Stuff Topic getting too big. Notify: ${var.datadog_monitor_notify_list}"
  escalation_message = "Escalation message @pagerduty"

  query = "avg:gcp.pubsub.subscription.num_undelivered_messages{project_id:terraform_gcp_test}"

  thresholds = {
    ok                = 0
    warning           = 1
    warning_recovery  = 0
    critical          = 2
    critical_recovery = 1
  }

  notify_no_data    = false
  renotify_interval = 1440

  notify_audit = false
  timeout_h    = 60
  include_tags = true

  # ignore any changes in silenced value; using silenced is deprecated in favor of downtimes
  lifecycle {
    ignore_changes = [silenced]
  }

  tags = [var.customer_name, var.project_name]
}

So I ended up just looking at the tests in the datadog terraform provider and noticing the query format they are testing.

  query = "avg(last_30m):avg:gcp.pubsub.subscription.num_undelivered_messages{project_id:${var.project_name},subscription_id:{project_id:terraform_gcp_test} > 2"

It seems you need to specify a time range and also add in a comparison threshold that matches your critical alert threshold. That was what was missing.