feat: support config via tags (#1)

Author: michaelwittig

README.md

@@ -23,6 +23,22 @@ terraform init
 terraform apply
 ```
 
+## Config via tags
+
+You can also configure this module by tagging the SQS queue (requires v1.0.0 or higher). Tags take precedence over variables (tags override variables).
+
+| tag key                                                            | default value                                                        | allowed values                                |
+| ------------------------------------------------------------------ | -------------------------------------------------------------------- | ----------------------------------------------|
+| `marbot`                                                           | on                                                                   | on,off                                        |
+| `marbot:approximate-age-of-oldest-message`                         | variable `approximate_age_of_oldest_message`                         | static,off                                    |
+| `marbot:approximate-age-of-oldest-message:threshold`               | variable `approximate_age_of_oldest_message_threshold`               | >= 0                                          |
+| `marbot:approximate-age-of-oldest-message:period`                  | variable `approximate_age_of_oldest_message_period`                  | <= 86400 and multiple of 60                   |
+| `marbot:approximate-age-of-oldest-message:evaluation-periods`      | variable `approximate_age_of_oldest_message_evaluation_periods`      | >= 1 and $period*$evaluation-periods <= 86400 |
+| `marbot:approximate-number-of-messages-visible`                    | variable `approximate_number_of_messages_visible`                    | static,off                                    |
+| `marbot:approximate-number-of-messages-visible:threshold`          | variable `approximate_number_of_messages_visible_threshold`          | >= 0                                          |
+| `marbot:approximate-number-of-messages-visible:period`             | variable `approximate_number_of_messages_visible_period`             | <= 86400 and multiple of 60                   |
+| `marbot:approximate-number-of-messages-visible:evaluation-periods` | variable `approximate_number_of_messages_visible_evaluation_periods` | >= 1 and $period*$evaluation-periods <= 86400 |
+
 ## Update procedure
 
 1. Update the `version`

main.tf

@@ -12,8 +12,27 @@ data "aws_caller_identity" "current" {}
 
 data "aws_region" "current" {}
 
+data "aws_sqs_queue" "queue" {
+  name = var.queue_name
+}
+
 locals {
   topic_arn = var.create_topic == false ? var.topic_arn : join("", aws_sns_topic.marbot.*.arn)
+  enabled   = var.enabled && lookup(data.aws_sqs_queue.queue.tags, "marbot", "on") != "off"
+
+  approximate_age_of_oldest_message                        = lookup(data.aws_sqs_queue.queue.tags, "marbot:approximate-age-of-oldest-message", var.approximate_age_of_oldest_message)
+  approximate_age_of_oldest_message_threshold              = try(tonumber(lookup(data.aws_sqs_queue.queue.tags, "marbot:approximate-age-of-oldest-message:threshold", var.approximate_age_of_oldest_message_threshold)), var.approximate_age_of_oldest_message_threshold)
+  approximate_age_of_oldest_message_period_raw             = try(tonumber(lookup(data.aws_sqs_queue.queue.tags, "marbot:approximate-age-of-oldest-message:period", var.approximate_age_of_oldest_message_period)), var.approximate_age_of_oldest_message_period)
+  approximate_age_of_oldest_message_period                 = min(max(floor(local.approximate_age_of_oldest_message_period_raw / 60) * 60, 60), 86400)
+  approximate_age_of_oldest_message_evaluation_periods_raw = try(tonumber(lookup(data.aws_sqs_queue.queue.tags, "marbot:approximate-age-of-oldest-message:evaluation-periods", var.approximate_age_of_oldest_message_evaluation_periods)), var.approximate_age_of_oldest_message_evaluation_periods)
+  approximate_age_of_oldest_message_evaluation_periods     = min(max(local.approximate_age_of_oldest_message_evaluation_periods_raw, 1), floor(86400 / local.approximate_age_of_oldest_message_period))
+
+  approximate_number_of_messages_visible                        = lookup(data.aws_sqs_queue.queue.tags, "marbot:approximate-number-of-messages-visible", var.approximate_number_of_messages_visible)
+  approximate_number_of_messages_visible_threshold              = try(tonumber(lookup(data.aws_sqs_queue.queue.tags, "marbot:approximate-number-of-messages-visible:threshold", var.approximate_number_of_messages_visible_threshold)), var.approximate_number_of_messages_visible_threshold)
+  approximate_number_of_messages_visible_period_raw             = try(tonumber(lookup(data.aws_sqs_queue.queue.tags, "marbot:approximate-number-of-messages-visible:period", var.approximate_number_of_messages_visible_period)), var.approximate_number_of_messages_visible_period)
+  approximate_number_of_messages_visible_period                 = min(max(floor(local.approximate_number_of_messages_visible_period_raw / 60) * 60, 60), 86400)
+  approximate_number_of_messages_visible_evaluation_periods_raw = try(tonumber(lookup(data.aws_sqs_queue.queue.tags, "marbot:approximate-number-of-messages-visible:evaluation-periods", var.approximate_number_of_messages_visible_evaluation_periods)), var.approximate_number_of_messages_visible_evaluation_periods)
+  approximate_number_of_messages_visible_evaluation_periods     = min(max(local.approximate_number_of_messages_visible_evaluation_periods_raw, 1), floor(86400 / local.approximate_number_of_messages_visible_period))
 }
 
 ##########################################################################
@@ -23,14 +42,14 @@ locals {
 ##########################################################################
 
 resource "aws_sns_topic" "marbot" {
-  count = (var.create_topic && var.enabled) ? 1 : 0
+  count = (var.create_topic && local.enabled) ? 1 : 0
 
   name_prefix = "marbot"
   tags        = var.tags
 }
 
 resource "aws_sns_topic_policy" "marbot" {
-  count = (var.create_topic && var.enabled) ? 1 : 0
+  count = (var.create_topic && local.enabled) ? 1 : 0
 
   arn    = join("", aws_sns_topic.marbot.*.arn)
   policy = data.aws_iam_policy_document.topic_policy.json
@@ -72,7 +91,7 @@ data "aws_iam_policy_document" "topic_policy" {
 
 resource "aws_sns_topic_subscription" "marbot" {
   depends_on = [aws_sns_topic_policy.marbot]
-  count      = (var.create_topic && var.enabled) ? 1 : 0
+  count      = (var.create_topic && local.enabled) ? 1 : 0
 
   topic_arn              = join("", aws_sns_topic.marbot.*.arn)
   protocol               = "https"
@@ -98,7 +117,7 @@ JSON
 
 resource "aws_cloudwatch_event_rule" "monitoring_jump_start_connection" {
   depends_on = [aws_sns_topic_subscription.marbot]
-  count      = (var.module_version_monitoring_enabled && var.enabled) ? 1 : 0
+  count      = (var.module_version_monitoring_enabled && local.enabled) ? 1 : 0
 
   name                = "marbot-sqs-queue-connection-${random_id.id8.hex}"
   description         = "Monitoring Jump Start connection (created by marbot)"
@@ -107,7 +126,7 @@ resource "aws_cloudwatch_event_rule" "monitoring_jump_start_connection" {
 }
 
 resource "aws_cloudwatch_event_target" "monitoring_jump_start_connection" {
-  count = (var.module_version_monitoring_enabled && var.enabled) ? 1 : 0
+  count = (var.module_version_monitoring_enabled && local.enabled) ? 1 : 0
 
   rule      = join("", aws_cloudwatch_event_rule.monitoring_jump_start_connection.*.name)
   target_id = "marbot"
@@ -116,7 +135,7 @@ resource "aws_cloudwatch_event_target" "monitoring_jump_start_connection" {
 {
   "Type": "monitoring-jump-start-tf-connection",
   "Module": "sqs-queue",
-  "Version": "0.7.0",
+  "Version": "1.0.0",
   "Partition": "${data.aws_partition.current.partition}",
   "AccountId": "${data.aws_caller_identity.current.account_id}",
   "Region": "${data.aws_region.current.name}"
@@ -138,17 +157,17 @@ resource "random_id" "id8" {
 
 resource "aws_cloudwatch_metric_alarm" "approximate_age_of_oldest_message" {
   depends_on = [aws_sns_topic_subscription.marbot]
-  count      = (var.approximate_age_of_oldest_message_threshold >= 0 && var.enabled) ? 1 : 0
+  count      = (local.approximate_age_of_oldest_message == "static" && local.enabled) ? 1 : 0
 
   alarm_name          = "marbot-sqs-queue-message-age-${random_id.id8.hex}"
   alarm_description   = "Queue contains old messages. Is message processing failing or is the message procesing capacity too low? (created by marbot)"
   namespace           = "AWS/SQS"
   metric_name         = "ApproximateAgeOfOldestMessage"
   statistic           = "Maximum"
-  period              = 60
-  evaluation_periods  = 1
+  period              = local.approximate_age_of_oldest_message_period
+  evaluation_periods  = local.approximate_age_of_oldest_message_evaluation_periods
   comparison_operator = "GreaterThanThreshold"
-  threshold           = var.approximate_age_of_oldest_message_threshold
+  threshold           = local.approximate_age_of_oldest_message_threshold
   alarm_actions       = [local.topic_arn]
   ok_actions          = [local.topic_arn]
   dimensions = {
@@ -162,17 +181,17 @@ resource "aws_cloudwatch_metric_alarm" "approximate_age_of_oldest_message" {
 
 resource "aws_cloudwatch_metric_alarm" "approximate_number_of_messages_visible" {
   depends_on = [aws_sns_topic_subscription.marbot]
-  count      = (var.approximate_number_of_messages_visible_threshold >= 0 && var.enabled) ? 1 : 0
+  count      = (local.approximate_number_of_messages_visible == "static" && local.enabled) ? 1 : 0
 
   alarm_name          = "marbot-sqs-queue-length-${random_id.id8.hex}"
   alarm_description   = "Queue contains too many messages. Is message processing failing or is the message procesing capacity too low? (created by marbot)"
   namespace           = "AWS/SQS"
   metric_name         = "ApproximateNumberOfMessagesVisible"
   statistic           = "Maximum"
-  period              = 60
-  evaluation_periods  = 1
+  period              = local.approximate_number_of_messages_visible_period
+  evaluation_periods  = local.approximate_number_of_messages_visible_evaluation_periods
   comparison_operator = "GreaterThanThreshold"
-  threshold           = var.approximate_number_of_messages_visible_threshold
+  threshold           = local.approximate_number_of_messages_visible_threshold
   alarm_actions       = [local.topic_arn]
   ok_actions          = [local.topic_arn]
   dimensions = {

variables.tf

@@ -1,3 +1,22 @@
+# We can not only check the var.topic_arn !="" because of the Terraform error:  The "count" value depends on resource attributes that cannot be determined until apply, so Terraform cannot predict how many instances will be created.
+variable "create_topic" {
+  type        = bool
+  description = "Create SNS topic? If set to false you must set topic_arn as well!"
+  default     = true
+}
+
+variable "topic_arn" {
+  type        = string
+  description = "Optional SNS topic ARN if create_topic := false (usually the output of the modules marbot-monitoring-basic or marbot-standalone-topic)."
+  default     = ""
+}
+
+variable "stage" {
+  type        = string
+  description = "marbot stage (never change this!)."
+  default     = "v1"
+}
+
 variable "endpoint_id" {
   type        = string
   description = "Your marbot endpoint ID (to get this value: select a channel where marbot belongs to and send a message like this: \"@marbot show me my endpoint id\")."
@@ -26,33 +45,54 @@ variable "queue_name" {
   description = "The SQS queue name that you want to monitor."
 }
 
+
+
+variable "approximate_age_of_oldest_message" {
+  type        = string
+  description = "Old messages (static|off)."
+  default     = "static"
+}
+
 variable "approximate_age_of_oldest_message_threshold" {
   type        = number
-  description = "The maximum age (in seconds) of a message in the queue (set to -1 to disable)."
+  description = "The maximum age (in seconds) of a message in the queue (>= 0)."
   default     = 600
 }
 
-variable "approximate_number_of_messages_visible_threshold" {
+variable "approximate_age_of_oldest_message_period" {
   type        = number
-  description = "The maximum number of messages in the queue waiting for processing (set to -1 to disable)"
-  default     = 10
+  description = "The period in seconds over which the specified statistic is applied (<= 86400 and multiple of 60)."
+  default     = 60
 }
 
-# We can not only check the var.topic_arn !="" because of the Terraform error:  The "count" value depends on resource attributes that cannot be determined until apply, so Terraform cannot predict how many instances will be created.
-variable "create_topic" {
-  type        = bool
-  description = "Create SNS topic? If set to false you must set topic_arn as well!"
-  default     = true
+variable "approximate_age_of_oldest_message_evaluation_periods" {
+  type        = number
+  description = "The number of periods over which data is compared to the specified threshold (>= 1 and $period*$evaluation_periods <= 86400)."
+  default     = 1
 }
 
-variable "topic_arn" {
+
+
+variable "approximate_number_of_messages_visible" {
   type        = string
-  description = "Optional SNS topic ARN if create_topic := false (usually the output of the modules marbot-monitoring-basic or marbot-standalone-topic)."
-  default     = ""
+  description = "Waiting messages (static|off)."
+  default     = "static"
 }
 
-variable "stage" {
-  type        = string
-  description = "marbot stage (never change this!)."
-  default     = "v1"
+variable "approximate_number_of_messages_visible_threshold" {
+  type        = number
+  description = "The maximum number of messages in the queue waiting for processing (>= 0)."
+  default     = 10
+}
+
+variable "approximate_number_of_messages_visible_period" {
+  type        = number
+  description = "The period in seconds over which the specified statistic is applied (<= 86400 and multiple of 60)."
+  default     = 60
+}
+
+variable "approximate_number_of_messages_visible_evaluation_periods" {
+  type        = number
+  description = "The number of periods over which data is compared to the specified threshold (>= 1 and $period*$evaluation_periods <= 86400)."
+  default     = 1
 }