Fix function app slot host id collision (#39)

pagopa · Jun 7, 2024 · 394638f · 394638f
1 parent c146916
commit 394638f
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Showing 4 changed files with 13 additions and 3 deletions.
diff --git a/infra/modules/azure_function_app/README.md b/infra/modules/azure_function_app/README.md
@@ -12,7 +12,7 @@
 
 | Name | Version |
 |------|---------|
-| <a name="provider_azurerm"></a> [azurerm](#provider\_azurerm) | 3.104.0 |
+| <a name="provider_azurerm"></a> [azurerm](#provider\_azurerm) | 3.107.0 |
 
 ## Modules
 

diff --git a/infra/modules/azure_function_app/function_app.tf b/infra/modules/azure_function_app/function_app.tf
@@ -1,5 +1,5 @@
 resource "azurerm_linux_function_app" "this" {
-  name                = "${local.project}-${var.environment.domain}-${var.environment.app_name}-func-${var.environment.instance_number}"
+  name                = local.function_app.name
   location            = var.environment.location
   resource_group_name = var.resource_group_name
 
@@ -43,6 +43,8 @@ resource "azurerm_linux_function_app" "this" {
       # https://learn.microsoft.com/en-us/azure/azure-functions/functions-reference?tabs=blob&pivots=programming-language-csharp#connecting-to-host-storage-with-an-identity
       SLOT_TASK_HUBNAME = "ProductionTaskHub",
     },
+    # https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0004#options-for-addressing-collisions
+    length(local.function_app.name) > 32 ? { AzureFunctionsWebHost__hostid = "production" } : {},
     var.app_settings,
     local.application_insights.enable ? {
       # https://docs.microsoft.com/en-us/azure/azure-monitor/app/sampling
@@ -55,6 +57,7 @@ resource "azurerm_linux_function_app" "this" {
       [
         "SLOT_TASK_HUBNAME",
       ],
+      length(local.function_app.name) > 32 ? ["AzureFunctionsWebHost__hostid"] : [],
       var.sticky_app_setting_names,
     )
   }

diff --git a/infra/modules/azure_function_app/function_app_slot.tf b/infra/modules/azure_function_app/function_app_slot.tf
@@ -1,7 +1,7 @@
 resource "azurerm_linux_function_app_slot" "this" {
   count = local.function_app.is_slot_enabled
 
-  name            = "staging"
+  name            = local.function_app_slot.name
   function_app_id = azurerm_linux_function_app.this.id
 
   storage_account_name          = azurerm_storage_account.this.name
@@ -44,6 +44,8 @@ resource "azurerm_linux_function_app_slot" "this" {
       # https://learn.microsoft.com/en-us/azure/azure-functions/functions-reference?tabs=blob&pivots=programming-language-csharp#connecting-to-host-storage-with-an-identity
       SLOT_TASK_HUBNAME = "StagingTaskHub",
     },
+    # https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0004#options-for-addressing-collisions
+    length("${azurerm_linux_function_app.this.name}-${local.function_app_slot.name}") > 32 ? { AzureFunctionsWebHost__hostid = local.function_app_slot.name } : {},
     var.slot_app_settings
   )
 

diff --git a/infra/modules/azure_function_app/locals.tf b/infra/modules/azure_function_app/locals.tf
@@ -7,11 +7,16 @@ locals {
   }
 
   function_app = {
+    name                   = "${local.project}-${var.environment.domain}-${var.environment.app_name}-func-${var.environment.instance_number}"
     sku_name               = var.tier == "test" ? "B1" : var.tier == "standard" ? "P0v3" : "P1v3"
     zone_balancing_enabled = var.tier != "test"
     is_slot_enabled        = var.tier == "test" ? 0 : 1
   }
 
+  function_app_slot = {
+    name = "staging"
+  }
+
   application_insights = {
     enable = var.application_insights_connection_string != null
   }