Merge pull request #11 from DNXLabs/feature/cloudfront-alarms

Adding CloudFront CW alarms

_variables.tf

@@ -135,4 +135,44 @@ variable "response_page_path" {
 variable "lambda_edge" {
   default     = []
   description = "Lambda EDGE configuration"
+}
+
+variable "default_threshold" {
+  description = "The default threshold for the metric."
+  default     = 5
+}
+
+variable "default_evaluation_periods" {
+  description = "The default amount of evaluation periods."
+  default     = 2
+}
+
+variable "default_period" {
+  description = "The default evaluation period."
+  default     = 60
+}
+
+variable "default_comparison_operator" {
+  description = "The default comparison operator."
+  default     = "GreaterThanOrEqualToThreshold"
+}
+
+variable "default_statistic" {
+  description = "The default statistic."
+  default     = "Average"
+}
+variable "alarms" {
+  type        = map(any)
+  default     = {}
+  description = <<EOF
+The keys of the map are the metric names. This list must be given as a comma-separated string.
+The following arguments are supported:
+  - comparison_operator: GreaterThanOrEqualToThreshold, GreaterThanThreshold, LessThanThreshold, LessThanOrEqualToThreshold
+  - evaluation_periods: The number of periods over which data is compared to the specified threshold.
+  - period: The period in seconds over which the specified statistic is applied.
+  - statistic: The statistic to apply to the alarm's associated metric.
+  - threshold: The number of occurances over a given period.
+  - actions: The actions to execute when the alarm transitions into an ALARM state (ARN). 
+  - ok_actions: The list of actions to execute when this alarm transitions into an OK state from any other state (ARN). 
+EOF
 }

cloudwatch-alarms-cloudfront.tf

@@ -0,0 +1,62 @@
+resource "aws_cloudwatch_metric_alarm" "cloufront_alarm" {
+  count = length(var.alarms)
+
+  alarm_name = format("cloudfront-%s-%s",
+    aws_cloudfront_distribution.default[0].id,
+    element(keys(var.alarms), count.index)
+  )
+
+  comparison_operator = lookup(
+    var.alarms[element(keys(var.alarms), count.index)],
+    "comparison_operator",
+    var.default_comparison_operator
+  )
+
+  evaluation_periods = lookup(
+    var.alarms[element(keys(var.alarms), count.index)],
+    "evaluation_periods",
+    var.default_evaluation_periods
+  )
+
+  metric_name = element(keys(var.alarms), count.index)
+
+  namespace = "AWS/CloudFront"
+
+  period = lookup(
+    var.alarms[element(keys(var.alarms), count.index)],
+    "period",
+    var.default_period
+  )
+
+  statistic = lookup(
+    var.alarms[element(keys(var.alarms), count.index)],
+    "statistic",
+    var.default_statistic
+  )
+
+  threshold = lookup(
+    var.alarms[element(keys(var.alarms), count.index)],
+    "threshold",
+    var.default_threshold
+  )
+
+  dimensions = {
+    DistributionId = aws_cloudfront_distribution.default[0].id
+    Region         = "Global"
+  }
+
+  alarm_actions = compact(split(",", lookup(
+    var.alarms[element(keys(var.alarms), count.index)],
+    "actions",
+    ""
+  )))
+
+  ok_actions = compact(split(",", lookup(
+    var.alarms[element(keys(var.alarms), count.index)],
+    "ok_actions",
+    ""
+  )))
+
+  insufficient_data_actions = []
+  treat_missing_data        = "ignore"
+}

examples/cloudfront-simple-alarm.tf

@@ -0,0 +1,24 @@
+resource "aws_s3_bucket" "app_frontend" {
+  bucket_prefix = "my-frontend-app-"
+  acl           = "private"
+}
+
+module "app_frontend" {
+  source = "git::https://github.com/DNXLabs/terraform-aws-static-app.git?ref=2.0.1" # Always check the latest version
+
+  name            = "my-frontend-app"
+  s3_bucket_id    = aws_s3_bucket.app_frontend.id
+  hostnames       = ["www.example.com"]
+  certificate_arn = "arn:aws:acm:us-east-1:<account-id>:certificate/<certificate-hash>" # Replace the <account-id> and <certificate-hash> from a valid certificate
+  hosted_zone     = "example.com"
+  hostname_create = true
+
+  alarms = {
+    "TotalErrorRate" = {
+      threshold = 1 #(%)
+    }
+    "5xxErrorRate" = {
+      threshold = 5 #(%)
+    }
+  }
+}