MON-289 add dropped connections monitor

middleware/nginx/inputs.tf

@@ -60,3 +60,38 @@ variable "nginx_connect_threshold_critical" {
   type        = "string"
   default     = "1.1754943508222875e-38"
 }
+
+variable "nginx_dropped_silenced" {
+  description = "Groups to mute for Nginx dropped connections monitor"
+  type        = "map"
+  default     = {}
+}
+
+variable "nginx_dropped_extra_tags" {
+  description = "Extra tags for Nginx dropped connections monitor"
+  type        = "list"
+  default     = []
+}
+
+variable "nginx_dropped_message" {
+  description = "Custom message for Nginx dropped connections monitor"
+  type        = "string"
+  default     = ""
+}
+
+variable "nginx_dropped_time_aggregator" {
+  description = "Monitor aggregator for Nginx dropped connections [available values: min, max or avg]"
+  type        = "string"
+  default     = "min"
+}
+
+variable "nginx_dropped_timeframe" {
+  description = "Monitor timeframe for Nginx dropped connections [available values: `last_#m` (1, 5, 10, 15, or 30), `last_#h` (1, 2, or 4), or `last_1d`]"
+  type        = "string"
+  default     = "last_5m"
+}
+
+variable "nginx_dropped_threshold_critical" {
+  description = "php fpm busy critical threshold"
+  default     = 0
+}

middleware/nginx/monitors-nginx.tf

@@ -27,3 +27,32 @@ resource "datadog_monitor" "datadog_nginx_process" {
 
   tags = ["env:${var.environment}", "type:middleware", "provider:nginx", "resource:nginx", "team:claranet", "created-by:terraform", "${var.nginx_connect_extra_tags}"]
 }
+
+resource "datadog_monitor" "datadog_nginx_dropped_connections" {
+  name    = "[${var.environment}] Nginx dropped connections {{#is_alert}}{{{comparator}}} {{threshold}} ({{value}}){{/is_alert}}{{#is_warning}}{{{comparator}}} {{warn_threshold}} ({{value}}){{/is_warning}}"
+  message = "${coalesce(var.nginx_dropped_message, var.message)}"
+
+  type = "metric alert"
+
+  query = "${var.nginx_dropped_time_aggregator}(${var.nginx_dropped_timeframe}):avg:nginx.net.conn_dropped_per_s${module.filter-tags.query_alert} by {host} > ${var.nginx_dropped_threshold_critical}"
+
+  thresholds {
+    warning  = "${var.nginx_dropped_threshold_warning}"
+    critical = "${var.nginx_dropped_threshold_critical}"
+  }
+
+  notify_no_data      = false
+  evaluation_delay    = "${var.evaluation_delay}"
+  new_host_delay      = "${var.new_host_delay}"
+  notify_audit        = false
+  timeout_h           = 0
+  include_tags        = true
+  locked              = false
+  require_full_window = true
+
+  silenced = "${var.nginx_dropped_silenced}"
+
+  tags = ["env:${var.environment}", "type:middleware", "provider:nginx", "resource:nginx", "team:claranet", "created-by:terraform", "${var.nginx_dropped_extra_tags}"]
+}
+
+