DTOSS-11646: Setup Container Apps container probes

We need to configure a container probe (liveness/readiness) for our Azure Container Apps deployment.
By default, the web application should only have a heath probe if the variable probe_path is set.
If probe_path is null then it's disabled.
Please note that we cannot do this for the Postgres DB container as there is no Django / restful interface to implement.

Author: mrlockstar

infrastructure/modules/container-app/main.tf

@@ -103,6 +103,20 @@ resource "azurerm_container_app" "main" {
           secret_name = lower(env.value.name)
         }
       }
+
+      dynamic "liveness_probe" {
+        for_each = local.probe_enabled ? [1] : []
+
+        content {
+          transport               = "HTTP"
+          path                    = var.probe_path
+          port                    = local.effective_liveness_port
+          initial_delay           = 45
+          interval_seconds        = 10
+          timeout                 = 2
+          failure_count_threshold = 4
+        }
+      }
     }
     min_replicas = var.min_replicas
   }
@@ -145,6 +159,7 @@ resource "azurerm_container_app" "main" {
       }
     }
   }
+
 }
 
 # Enable Microsoft Entra ID authentication if specified

infrastructure/modules/container-app/variables.tf

@@ -93,6 +93,12 @@ variable "exposed_port" {
   default     = null
 }
 
+variable "liveness_probe_port" {
+  description = "Port for the liveness probe to check. Default is var.port."
+  type        = number
+  default     = null
+}
+
 variable "memory" {
   description = "Memory allocated to the app (GiB). Also dictates the CPU allocation: CPU(%)=MEMORY(Gi)/2. Maximum: 4Gi"
   default     = "0.5"
@@ -190,6 +196,12 @@ variable "replica_restart_alert_threshold" {
   default     = 1
 }
 
+variable "probe_path" {
+  description = "Path for the liveness probe. If null, liveness probe is disabled."
+  type        = string
+  default     = null
+}
+
 locals {
   memory = "${var.memory}Gi"
   cpu    = var.memory / 2
@@ -202,5 +214,7 @@ locals {
     PT6H  = "PT5M"
     PT12H = "PT5M"
   }
-  alert_frequency = local.alert_frequency_map[var.alert_window_size]
+  alert_frequency         = local.alert_frequency_map[var.alert_window_size]
+  probe_enabled           = var.probe_path != null
+  effective_liveness_port = var.liveness_probe_port != null ? var.liveness_probe_port : var.port
 }

infrastructure/modules/dashboard/variables.tf

@@ -24,7 +24,7 @@ variable "tags" {
 }
 
 variable "dashboard_properties" {
-  type = string
-  default = "{}"
+  type        = string
+  default     = "{}"
   description = "JSON data representing dashboard body. See above for details on how to obtain this from the Portal."
 }