cloudwatch.tf

locals {
  cloudwatch_alarm_default_thresholds = {
    "database_connections" = 500
    "cpu_utilization"      = 70
    "disk_queue_depth"     = 20
    "aurora_replica_lag"   = 2000
    "freeable_memory"      = 200000000
    "swap_usage"           = 100000000
  }

  cloudwatch_create_alarms = var.create_resources && var.cloudwatch_create_alarms ? true : false
}

resource "aws_cloudwatch_metric_alarm" "disk_queue_depth" {
  count               = local.cloudwatch_create_alarms ? 1 : 0
  alarm_name          = "rds-${aws_rds_cluster.main[0].id}-writer-DiskQueueDepth"
  comparison_operator = "GreaterThanOrEqualToThreshold"
  evaluation_periods  = "1"
  metric_name         = "DiskQueueDepth"
  namespace           = "AWS/RDS"
  period              = "60"
  statistic           = "Maximum"
  threshold = lookup(
    var.cloudwatch_alarm_default_thresholds,
    "disk_queue_depth",
    local.cloudwatch_alarm_default_thresholds["disk_queue_depth"],
  )
  alarm_description = "RDS Maximum DiskQueueDepth for RDS aurora cluster ${aws_rds_cluster.main[0].id} writer"
  alarm_actions     = var.cloudwatch_alarm_actions
  ok_actions        = var.cloudwatch_alarm_actions

  dimensions = {
    DBClusterIdentifier = aws_rds_cluster.main[0].id
    Role                = "WRITER"
  }
}

resource "aws_cloudwatch_metric_alarm" "database_connections_writer" {
  count               = local.cloudwatch_create_alarms ? 1 : 0
  alarm_name          = "rds-${aws_rds_cluster.main[0].id}-writer-DatabaseConnections"
  comparison_operator = "GreaterThanOrEqualToThreshold"
  evaluation_periods  = "1"
  metric_name         = "DatabaseConnections"
  namespace           = "AWS/RDS"
  period              = "60"
  statistic           = "Sum"
  threshold = lookup(
    var.cloudwatch_alarm_default_thresholds,
    "database_connections",
    local.cloudwatch_alarm_default_thresholds["database_connections"],
  )
  alarm_description = "RDS Maximum connection for RDS aurora cluster ${aws_rds_cluster.main[0].id} writer"
  alarm_actions     = var.cloudwatch_alarm_actions
  ok_actions        = var.cloudwatch_alarm_actions

  dimensions = {
    DBClusterIdentifier = aws_rds_cluster.main[0].id
    Role                = "WRITER"
  }
}

resource "aws_cloudwatch_metric_alarm" "database_connections_reader" {
  count               = local.cloudwatch_create_alarms && var.replica_count > 0 ? 1 : 0
  alarm_name          = "rds-${aws_rds_cluster.main[0].id}-reader-DatabaseConnections"
  comparison_operator = "GreaterThanOrEqualToThreshold"
  evaluation_periods  = "1"
  metric_name         = "DatabaseConnections"
  namespace           = "AWS/RDS"
  period              = "60"
  statistic           = "Maximum"
  threshold = lookup(
    var.cloudwatch_alarm_default_thresholds,
    "database_connections",
    local.cloudwatch_alarm_default_thresholds["database_connections"],
  )
  alarm_description = "RDS Maximum connection for RDS aurora cluster ${aws_rds_cluster.main[0].id} reader(s)"
  alarm_actions     = var.cloudwatch_alarm_actions
  ok_actions        = var.cloudwatch_alarm_actions

  dimensions = {
    DBClusterIdentifier = aws_rds_cluster.main[0].id
    Role                = "READER"
  }
}

resource "aws_cloudwatch_metric_alarm" "cpu_utilization_writer" {
  count               = local.cloudwatch_create_alarms ? 1 : 0
  alarm_name          = "rds-${aws_rds_cluster.main[0].id}-writer-CPU"
  comparison_operator = "GreaterThanOrEqualToThreshold"
  evaluation_periods  = "2"
  metric_name         = "CPUUtilization"
  namespace           = "AWS/RDS"
  period              = "60"
  statistic           = "Maximum"
  threshold = lookup(
    var.cloudwatch_alarm_default_thresholds,
    "cpu_utilization",
    local.cloudwatch_alarm_default_thresholds["cpu_utilization"],
  )
  alarm_description = "RDS CPU for RDS aurora cluster ${aws_rds_cluster.main[0].id} writer"
  alarm_actions     = var.cloudwatch_alarm_actions
  ok_actions        = var.cloudwatch_alarm_actions

  dimensions = {
    DBClusterIdentifier = aws_rds_cluster.main[0].id
    Role                = "WRITER"
  }
}

resource "aws_cloudwatch_metric_alarm" "cpu_utilization_reader" {
  count               = local.cloudwatch_create_alarms && var.replica_count > 0 ? 1 : 0
  alarm_name          = "rds-${aws_rds_cluster.main[0].id}-reader-CPU"
  comparison_operator = "GreaterThanOrEqualToThreshold"
  evaluation_periods  = "2"
  metric_name         = "CPUUtilization"
  namespace           = "AWS/RDS"
  period              = "60"
  statistic           = "Maximum"
  threshold = lookup(
    var.cloudwatch_alarm_default_thresholds,
    "cpu_utilization",
    local.cloudwatch_alarm_default_thresholds["cpu_utilization"],
  )
  alarm_description = "RDS CPU for RDS aurora cluster ${aws_rds_cluster.main[0].id} reader(s)"
  alarm_actions     = var.cloudwatch_alarm_actions
  ok_actions        = var.cloudwatch_alarm_actions

  dimensions = {
    DBClusterIdentifier = aws_rds_cluster.main[0].id
    Role                = "READER"
  }
}

resource "aws_cloudwatch_metric_alarm" "aurora_replica_lag" {
  count               = local.cloudwatch_create_alarms && var.replica_count > 0 ? 1 : 0
  alarm_name          = "rds-${aws_rds_cluster.main[0].id}-reader-AuroraReplicaLag"
  comparison_operator = "GreaterThanOrEqualToThreshold"
  evaluation_periods  = "5"
  metric_name         = "AuroraReplicaLag"
  namespace           = "AWS/RDS"
  period              = "60"
  statistic           = "Maximum"
  threshold = lookup(
    var.cloudwatch_alarm_default_thresholds,
    "aurora_replica_lag",
    local.cloudwatch_alarm_default_thresholds["aurora_replica_lag"],
  )
  alarm_description = "RDS CPU for RDS aurora cluster ${aws_rds_cluster.main[0].id}"
  alarm_actions     = var.cloudwatch_alarm_actions
  ok_actions        = var.cloudwatch_alarm_actions

  dimensions = {
    DBClusterIdentifier = aws_rds_cluster.main[0].id
    Role                = "READER"
  }
}

resource "aws_cloudwatch_metric_alarm" "swap_usage_writer" {
  count               = local.cloudwatch_create_alarms ? 1 : 0
  alarm_name          = "rds-${aws_rds_cluster.main[0].id}-writer-SwapUsage"
  comparison_operator = "GreaterThanOrEqualToThreshold"
  evaluation_periods  = "2"
  metric_name         = "SwapUsage"
  namespace           = "AWS/RDS"
  period              = "60"
  statistic           = "Maximum"
  threshold = lookup(
    var.cloudwatch_alarm_default_thresholds,
    "swap_usage",
    local.cloudwatch_alarm_default_thresholds["swap_usage"],
  )
  alarm_description = "RDS swap usage for RDS aurora cluster ${aws_rds_cluster.main[0].id} writer"
  alarm_actions     = var.cloudwatch_alarm_actions
  ok_actions        = var.cloudwatch_alarm_actions

  dimensions = {
    DBClusterIdentifier = aws_rds_cluster.main[0].id
    Role                = "WRITER"
  }
}

resource "aws_cloudwatch_metric_alarm" "swap_usage_reader" {
  count               = local.cloudwatch_create_alarms && var.replica_count > 0 ? 1 : 0
  alarm_name          = "rds-${aws_rds_cluster.main[0].id}-reader-SwapUsage"
  comparison_operator = "GreaterThanOrEqualToThreshold"
  evaluation_periods  = "2"
  metric_name         = "SwapUsage"
  namespace           = "AWS/RDS"
  period              = "60"
  statistic           = "Maximum"
  threshold = lookup(
    var.cloudwatch_alarm_default_thresholds,
    "swap_usage",
    local.cloudwatch_alarm_default_thresholds["swap_usage"],
  )
  alarm_description = "RDS swap usage for RDS aurora cluster ${aws_rds_cluster.main[0].id} reader(s)"
  alarm_actions     = var.cloudwatch_alarm_actions
  ok_actions        = var.cloudwatch_alarm_actions

  dimensions = {
    DBClusterIdentifier = aws_rds_cluster.main[0].id
    Role                = "READER"
  }
}

resource "aws_cloudwatch_metric_alarm" "freeable_memory_writer" {
  count               = local.cloudwatch_create_alarms ? 1 : 0
  alarm_name          = "rds-${aws_rds_cluster.main[0].id}-writer-FreeableMemory"
  comparison_operator = "LessThanOrEqualToThreshold"
  evaluation_periods  = "2"
  metric_name         = "FreeableMemory"
  namespace           = "AWS/RDS"
  period              = "60"
  statistic           = "Minimum"
  threshold = lookup(
    var.cloudwatch_alarm_default_thresholds,
    "freeable_memory",
    local.cloudwatch_alarm_default_thresholds["freeable_memory"],
  )
  alarm_description = "RDS freeable memory for RDS aurora cluster ${aws_rds_cluster.main[0].id} writer"
  alarm_actions     = var.cloudwatch_alarm_actions
  ok_actions        = var.cloudwatch_alarm_actions

  dimensions = {
    DBClusterIdentifier = aws_rds_cluster.main[0].id
    Role                = "WRITER"
  }
}

resource "aws_cloudwatch_metric_alarm" "freeable_memory_reader" {
  count               = local.cloudwatch_create_alarms && var.replica_count > 0 ? 1 : 0
  alarm_name          = "rds-${aws_rds_cluster.main[0].id}-reader-FreeableMemory"
  comparison_operator = "LessThanOrEqualToThreshold"
  evaluation_periods  = "2"
  metric_name         = "FreeableMemory"
  namespace           = "AWS/RDS"
  period              = "60"
  statistic           = "Minimum"
  threshold = lookup(
    var.cloudwatch_alarm_default_thresholds,
    "freeable_memory",
    local.cloudwatch_alarm_default_thresholds["freeable_memory"],
  )
  alarm_description = "RDS freeable memory for RDS aurora cluster ${aws_rds_cluster.main[0].id} reader(s)"
  alarm_actions     = var.cloudwatch_alarm_actions
  ok_actions        = var.cloudwatch_alarm_actions

  dimensions = {
    DBClusterIdentifier = aws_rds_cluster.main[0].id
    Role                = "READER"
  }
}

resource "aws_cloudwatch_log_group" "this" {
  for_each = toset([for log in var.enabled_cloudwatch_logs_exports : log if var.create_cloudwatch_log_group])

  name              = "/aws/rds/instance/${var.identifier_prefix}${var.name}/${each.value}"
  retention_in_days = var.cloudwatch_log_group_retention_in_days

  tags = var.tags
}