From daa340ff8099b91f64b98d3175ca9d7458cddd60 Mon Sep 17 00:00:00 2001
From: Roman Volykh <rvolykh@gmail.com>
Date: Fri, 19 Dec 2025 12:30:24 +0200
Subject: [PATCH] fix: Specify Lambda concurrent executions

---
 infra/cmd_poweron.tf                | 5 +++--
 infra/main.tf                       | 5 +++--
 infra/modules/alerting/telegram.tf  | 2 +-
 infra/modules/alerting/variables.tf | 5 +++++
 infra/modules/handler/main.tf       | 2 +-
 infra/modules/handler/variables.tf  | 5 +++++
 infra/observability.tf              | 9 +++++----
 7 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/infra/cmd_poweron.tf b/infra/cmd_poweron.tf
index d4c9b8e..7b166e6 100644
--- a/infra/cmd_poweron.tf
+++ b/infra/cmd_poweron.tf
@@ -9,8 +9,9 @@ module "telegram_bot_queue_cmd_poweron" {
 module "telegram_bot_cmd_poweron" {
   source = "./modules/handler"
 
-  function_name = "telegram-bot-cmd-poweron"
-  source_path   = "${path.root}/../apps/poweron"
+  function_name                  = "telegram-bot-cmd-poweron"
+  reserved_concurrent_executions = 3
+  source_path                    = "${path.root}/../apps/poweron"
 
   sqs_batch_size = 10
   sqs_queue_arn  = module.telegram_bot_queue_cmd_poweron.sqs_queue_arn
diff --git a/infra/main.tf b/infra/main.tf
index b8506d8..eb12aa3 100644
--- a/infra/main.tf
+++ b/infra/main.tf
@@ -42,8 +42,9 @@ module "telegram_bot_api" {
 module "telegram_bot_handler_mux" {
   source = "./modules/handler"
 
-  function_name = "telegram-bot-mux"
-  source_path   = "${path.root}/../apps/mux"
+  function_name                  = "telegram-bot-mux"
+  reserved_concurrent_executions = 3
+  source_path                    = "${path.root}/../apps/mux"
 
   sqs_batch_size = 10
   sqs_queue_arn  = module.telegram_bot_queue_mux.sqs_queue_arn
diff --git a/infra/modules/alerting/telegram.tf b/infra/modules/alerting/telegram.tf
index edbb6a0..6626daa 100644
--- a/infra/modules/alerting/telegram.tf
+++ b/infra/modules/alerting/telegram.tf
@@ -7,7 +7,7 @@ resource "aws_lambda_function" "telegram" {
   runtime                        = "provided.al2023"
   timeout                        = 10
   memory_size                    = 128
-  reserved_concurrent_executions = 10
+  reserved_concurrent_executions = var.reserved_concurrent_executions
 
   environment {
     variables = {
diff --git a/infra/modules/alerting/variables.tf b/infra/modules/alerting/variables.tf
index 2e78d85..a2a56e3 100644
--- a/infra/modules/alerting/variables.tf
+++ b/infra/modules/alerting/variables.tf
@@ -3,6 +3,11 @@ variable "name" {
   type        = string
 }
 
+variable "reserved_concurrent_executions" {
+  description = "Reserved concurrent executions for the Lambda function"
+  type        = number
+}
+
 variable "emails" {
   description = "Emails to subscribe to the SNS topic"
   type        = list(string)
diff --git a/infra/modules/handler/main.tf b/infra/modules/handler/main.tf
index ea2fbb7..15ec303 100644
--- a/infra/modules/handler/main.tf
+++ b/infra/modules/handler/main.tf
@@ -7,7 +7,7 @@ resource "aws_lambda_function" "this" {
   runtime                        = "provided.al2023"
   timeout                        = var.timeout
   memory_size                    = var.memory_size
-  reserved_concurrent_executions = 10
+  reserved_concurrent_executions = var.reserved_concurrent_executions
 
   environment {
     variables = var.environment_variables
diff --git a/infra/modules/handler/variables.tf b/infra/modules/handler/variables.tf
index 1812d33..4335c22 100644
--- a/infra/modules/handler/variables.tf
+++ b/infra/modules/handler/variables.tf
@@ -3,6 +3,11 @@ variable "function_name" {
   type        = string
 }
 
+variable "reserved_concurrent_executions" {
+  description = "Reserved concurrent executions for the Lambda function"
+  type        = number
+}
+
 variable "source_path" {
   description = "Path to the directory containing main.go (the module will build the binary and create a ZIP)"
   type        = string
diff --git a/infra/observability.tf b/infra/observability.tf
index cdc2734..d0710fb 100644
--- a/infra/observability.tf
+++ b/infra/observability.tf
@@ -35,10 +35,11 @@ resource "aws_cloudwatch_metric_alarm" "non_empty_dlq" {
 module "telegram_bot_alerting" {
   source = "./modules/alerting"
 
-  name                         = "telegram-bot-alerting"
-  emails                       = var.alerting_emails
-  telegram_chat_id             = var.alerting_telegram_chat_id
-  ssm_param_telegram_api_token = module.telegram_bot_api_token.name
+  name                           = "telegram-bot-alerting"
+  reserved_concurrent_executions = 2
+  emails                         = var.alerting_emails
+  telegram_chat_id               = var.alerting_telegram_chat_id
+  ssm_param_telegram_api_token   = module.telegram_bot_api_token.name
   role_policies = [
     // policy 0
     [