created custom metrics auto scraping

aks/application/README.md

@@ -96,6 +96,8 @@ If `azure_enable_monitoring` is `true`, it’s expected that the following resou
 - A resource group named `${azure_resource_prefix}-${service_short}-mn-rg` (where `mn` stands for monitoring and `rg` stands for resource group).
 - A monitor action group named `${azure_resource_prefix}-${service_name}` within the above resource group.
 
+If `enable_prometheus_monitoring` is `true` then  custom metrics are scraped for the application
+
 ## Outputs
 
 ### `hostname`

aks/application/resources.tf

@@ -5,6 +5,11 @@ locals {
   http_probe_enabled = var.is_web && var.probe_path != null
   exec_probe_enabled = !var.is_web && length(var.probe_command) != 0
   probe_enabled      = local.http_probe_enabled || local.exec_probe_enabled
+  prometheus_scrape_annotations = {
+    "prometheus.io/scrape" = "true"
+    "prometheus.io/path"   = "/metrics"
+    "prometheus.io/port"   = var.web_port
+  }
 }
 
 resource "kubernetes_deployment" "main" {
@@ -27,6 +32,9 @@ resource "kubernetes_deployment" "main" {
         labels = {
           app = local.app_name
         }
+
+        annotations = var.enable_prometheus_monitoring ? local.prometheus_scrape_annotations : {}
+
       }
 
       spec {

aks/application/tfdocs.md

@@ -35,6 +35,7 @@ No modules.
 | <a name="input_cluster_configuration_map"></a> [cluster\_configuration\_map](#input\_cluster\_configuration\_map) | Configuration map for the cluster | <pre>object({<br>    resource_group_name = string,<br>    resource_prefix     = string,<br>    dns_zone_prefix     = optional(string),<br>    cpu_min             = number<br>  })</pre> | n/a | yes |
 | <a name="input_command"></a> [command](#input\_command) | Custom command that overwrites Docker image | `list(string)` | `[]` | no |
 | <a name="input_docker_image"></a> [docker\_image](#input\_docker\_image) | Path to the docker image | `string` | n/a | yes |
+| <a name="input_enable_prometheus_monitoring"></a> [enable\_prometheus\_monitoring](#input\_enable\_prometheus\_monitoring) | a boolean to indicate whether to scrape(true) custom metrics for application or not(false) | `bool` | `false` | no |
 | <a name="input_environment"></a> [environment](#input\_environment) | Current application environment | `string` | n/a | yes |
 | <a name="input_github_personal_access_token"></a> [github\_personal\_access\_token](#input\_github\_personal\_access\_token) | Github Personal Access Token (PAT) of github\_username | `string` | `null` | no |
 | <a name="input_github_username"></a> [github\_username](#input\_github\_username) | Github user authorised to access the private registry | `string` | `null` | no |

aks/application/variables.tf

@@ -104,6 +104,12 @@ variable "probe_path" {
   description = "Path for the liveness and startup probe. The probe can be disabled by setting this to null."
 }
 
+variable "enable_prometheus_monitoring" {
+  type        = bool
+  default     = false
+  description = " a boolean to indicate whether to scrape(true) custom metrics for application or not(false)"
+}
+
 variable "probe_command" {
   type        = list(string)
   nullable    = false