Implement Memcached Module (#1)

* Init

* Update README.md

* Use label module

* Address PR comments

* Address PR comments

README.md

@@ -1 +1 @@
-# tf-memcache
+# tf_memcached

main.tf

@@ -0,0 +1,150 @@
+# Define composite variables for resources
+module "label" {
+  source    = "git::https://github.com/cloudposse/tf_label.git?ref=tags/0.1.0"
+  namespace = "${var.namespace}"
+  name      = "${var.name}"
+  stage     = "${var.stage}"
+}
+
+resource "null_resource" "host" {
+  count = "${var.cluster_size}"
+
+  triggers = {
+    name = "${replace(aws_elasticache_cluster.default.cluster_address, ".cfg.", format(".%04d.", count.index + 1))}:11211"
+  }
+
+  lifecycle {
+    create_before_destroy = true
+  }
+}
+
+#
+# Security Group Resources
+#
+resource "aws_security_group" "default" {
+  vpc_id = "${var.vpc_id}"
+  name   = "${module.label.id}"
+
+  ingress {
+    from_port       = "11211"                    # Memcache
+    to_port         = "11211"
+    protocol        = "tcp"
+    security_groups = ["${var.security_groups}"]
+  }
+
+  egress {
+    from_port   = 0
+    to_port     = 0
+    protocol    = "-1"
+    cidr_blocks = ["0.0.0.0/0"]
+  }
+
+  tags {
+    Name      = "${module.label.id}"
+    Namespace = "${var.namespace}"
+    Stage     = "${var.stage}"
+  }
+}
+
+resource "aws_elasticache_subnet_group" "default" {
+  name       = "${module.label.id}"
+  subnet_ids = ["${var.subnets}"]
+}
+
+resource "aws_elasticache_parameter_group" "default" {
+  name   = "${module.label.id}"
+  family = "memcached1.4"
+
+  parameter {
+    name  = "max_item_size"
+    value = "${var.max_item_size}"
+  }
+}
+
+#
+# ElastiCache Resources
+#
+resource "aws_elasticache_cluster" "default" {
+  cluster_id             = "${module.label.id}"
+  engine                 = "memcached"
+  engine_version         = "${var.engine_version}"
+  node_type              = "${var.instance_type}"
+  num_cache_nodes        = "${var.cluster_size}"
+  parameter_group_name   = "${aws_elasticache_parameter_group.default.name}"
+  subnet_group_name      = "${aws_elasticache_subnet_group.default.name}"
+  security_group_ids     = ["${aws_security_group.default.id}"]
+  maintenance_window     = "${var.maintenance_window}"
+  notification_topic_arn = "${var.notification_topic_arn}"
+  port                   = "11211"
+  az_mode                = "${var.cluster_size == 1 ? "single-az" : "cross-az" }"
+  availability_zones     = ["${slice(var.availability_zones, 0, var.cluster_size)}"]
+
+  tags {
+    Name      = "${module.label.id}"
+    Namespace = "${var.namespace}"
+    Stage     = "${var.stage}"
+  }
+}
+
+#
+# CloudWatch Resources
+#
+resource "aws_cloudwatch_metric_alarm" "cache_cpu" {
+  alarm_name          = "${module.label.id}-cpu-utilization"
+  alarm_description   = "Memcached cluster CPU utilization"
+  comparison_operator = "GreaterThanThreshold"
+  evaluation_periods  = "1"
+  metric_name         = "CPUUtilization"
+  namespace           = "AWS/ElastiCache"
+  period              = "300"
+  statistic           = "Average"
+
+  threshold = "${var.alarm_cpu_threshold_percent}"
+
+  dimensions {
+    CacheClusterId = "${module.label.id}"
+  }
+
+  alarm_actions = ["${var.alarm_actions}"]
+  depends_on    = ["aws_elasticache_cluster.default"]
+}
+
+resource "aws_cloudwatch_metric_alarm" "cache_memory" {
+  alarm_name          = "${module.label.id}-freeable-memory"
+  alarm_description   = "Memcached cluster freeable memory"
+  comparison_operator = "LessThanThreshold"
+  evaluation_periods  = "1"
+  metric_name         = "FreeableMemory"
+  namespace           = "AWS/ElastiCache"
+  period              = "60"
+  statistic           = "Average"
+
+  threshold = "${var.alarm_memory_threshold_bytes}"
+
+  dimensions {
+    CacheClusterId = "${module.label.id}"
+  }
+
+  alarm_actions = ["${var.alarm_actions}"]
+  depends_on    = ["aws_elasticache_cluster.default"]
+}
+
+module "dns" {
+  source    = "git::https://github.com/cloudposse/tf_hostname.git?ref=tags/0.1.0"
+  namespace = "${var.namespace}"
+  name      = "${var.name}"
+  stage     = "${var.stage}"
+  ttl       = 60
+  zone_id   = "${var.zone_id}"
+  records   = ["${aws_elasticache_cluster.default.cluster_address}"]
+}
+
+module "dns_config" {
+  source    = "git::https://github.com/cloudposse/tf_hostname.git?ref=tags/0.1.0"
+  namespace = "${var.namespace}"
+  name      = "config.${var.name}"
+  stage     = "${var.stage}"
+  ttl       = 60
+  zone_id   = "${var.zone_id}"
+  records   = ["${aws_elasticache_cluster.default.configuration_endpoint}"]
+}

output.tf

@@ -0,0 +1,19 @@
+output "id" {
+  value = "${aws_elasticache_cluster.default.id}"
+}
+
+output "security_group_id" {
+  value = "${aws_security_group.default.id}"
+}
+
+output "port" {
+  value = "11211"
+}
+
+output "config_host" {
+  value = "${module.dns_config.hostname}"
+}
+
+output "hosts" {
+  value = "${join(",", null_resource.host.*.triggers.name)}"
+}

variables.tf

@@ -0,0 +1,72 @@
+variable "namespace" {
+  default = "global"
+}
+
+variable "stage" {
+  default = "default"
+}
+
+variable "name" {
+  default = "memcache"
+}
+
+variable "security_groups" {
+  type = "list"
+}
+
+variable "vpc_id" {
+  default = ""
+}
+
+variable "max_item_size" {
+  default = "10485760"
+}
+
+variable "subnets" {
+  type    = "list"
+  default = []
+}
+
+variable "maintenance_window" {
+  default = "wed:03:00-wed:04:00"
+}
+
+variable "cluster_size" {
+  default = "1"
+}
+
+variable "instance_type" {
+  default = "cache.t2.micro"
+}
+
+variable "engine_version" {
+  default = "1.4.33"
+}
+
+variable "notification_topic_arn" {
+  default = ""
+}
+
+variable "alarm_cpu_threshold_percent" {
+  default = "75"
+}
+
+variable "alarm_memory_threshold_bytes" {
+  # 10MB
+  default = "10000000"
+}
+
+variable "alarm_actions" {
+  type    = "list"
+  default = []
+}
+
+variable "apply_immediately" {
+  default = "true"
+}
+
+variable "availability_zones" {
+  type = "list"
+}
+
+variable "zone_id" {}