modules/slos/main.tf

data "google_project" "project" {
  project_id = var.project_id
}

resource "google_monitoring_service" "service" {
  project      = var.project_id
  service_id   = var.service_name
  display_name = var.service_name

  basic_service {
    service_type = "ISTIO_CANONICAL_SERVICE"
    service_labels = {
      mesh_uid                    = "proj-${data.google_project.project.number}"
      canonical_service_namespace = var.service_name
      canonical_service           = var.service_name
    }
  }
}


module "slo_latency" {
  source = "terraform-google-modules/slo/google//modules/slo-native"
  config = {
    project_id        = var.project_id
    service           = var.service_name
    slo_id            = "${var.service_name}-latency-slo"
    display_name      = "Latency - ${var.latency_threshold}ms - ${var.latency_goal} - Calendar ${var.latency_calendar_period} Day"
    goal              = var.latency_goal
    calendar_period   = var.latency_calendar_period
    type              = "basic_sli"
    method            = "latency"
    latency_threshold = "${var.latency_threshold}s"
  }
  depends_on = [google_monitoring_service.service]
}


resource "google_monitoring_alert_policy" "latency_alert_policy" {
  project      = var.project_id
  display_name = "${var.service_name}-latency-alert"
  combiner     = "OR"
  conditions {
    display_name = " Burn rate for ${var.service_name} Latency with ${var.latency_alert_threshold} for ${var.latency_alert_lookback_duration}s lookback period"
    condition_threshold {
      filter     = "select_slo_burn_rate(${module.slo_latency.name},${var.latency_alert_lookback_duration}s)"
      duration   = "0s"
      comparison = "COMPARISON_GT"
    }
  }
}

module "slo_availability" {
  source = "terraform-google-modules/slo/google//modules/slo-native"
  config = {
    project_id      = var.project_id
    service         = var.service_name
    slo_id          = "${var.service_name}-availability-slo"
    display_name    = "Availability - ${var.availability_goal} - Calendar ${var.availability_calendar_period} Day"
    goal            = var.availability_goal
    calendar_period = var.availability_calendar_period
    type            = "basic_sli"
    method          = "availability"
  }
  depends_on = [google_monitoring_service.service]
}


resource "google_monitoring_alert_policy" "availability_alert_policy" {
  project      = var.project_id
  display_name = "${var.service_name}-availability-alert"
  combiner     = "OR"
  conditions {
    display_name = " Burn rate for ${var.service_name} Availability with ${var.availability_alert_threshold} for ${var.availability_alert_lookback_duration}s lookback period"
    condition_threshold {
      filter     = "select_slo_burn_rate(${module.slo_availability.name},${var.availability_alert_lookback_duration}s)"
      duration   = "0s"
      comparison = "COMPARISON_GT"
    }
  }
}