167 add cache (#177)

* added cache

* allow EKS worker to access cache store

* add cache service with template

* small fix

* updated after review

* set default: no cache

* small fix

* a few changes after review

Author: sshi100

templates/kubernetes/terraform/environments/prod/main.tf

@@ -84,4 +84,6 @@ module "kubernetes" {
 
   notification_service_enabled          = <%if eq (index .Params `sendgridApiKey`) "" %>false<% else %>true<% end %>
   notification_service_highly_available = true
+
+  cache_store =  "<% index .Params `cacheStore` %>"
 }

templates/kubernetes/terraform/environments/stage/main.tf

@@ -83,4 +83,6 @@ module "kubernetes" {
 
   notification_service_enabled          = <%if eq (index .Params `sendgridApiKey`) "" %>false<% else %>true<% end %>
   notification_service_highly_available = false
+
+  cache_store = "<% index .Params `cacheStore` %>"
 }

templates/kubernetes/terraform/modules/kubernetes/cache_service.tf

@@ -0,0 +1,29 @@
+data "aws_elasticache_replication_group" "redis" {
+  count = var.cache_store == "redis" ? 1 : 0
+
+  replication_group_id = "${var.project}-${var.environment}-redis"
+}
+
+data "aws_elasticache_cluster" "memcached" {
+  count = var.cache_store == "memcached" ? 1 : 0
+
+  cluster_id = "${var.project}-${var.environment}-memcached"
+}
+
+locals {
+  endpoint_address = var.cache_store == "redis" ? data.aws_elasticache_replication_group.redis[0].primary_endpoint_address : var.cache_store == "memcached" ? data.aws_elasticache_cluster.memcached[0].cluster_address : ""
+}
+
+resource "kubernetes_service" "app_cache" {
+  count = local.endpoint_address == "" ? 0 : 1
+
+  ## this should match the deployable backend's name/namespace
+  metadata {
+    namespace = kubernetes_namespace.app_namespace.metadata[0].name
+    name      = "cache-${var.cache_store}"
+  }
+  spec {
+    type          = "ExternalName"
+    external_name = local.endpoint_address
+  }
+}

templates/kubernetes/terraform/modules/kubernetes/variables.tf

@@ -141,3 +141,9 @@ variable "notification_service_highly_available" {
   type        = bool
   default     = true
 }
+
+variable "cache_store" {
+  description = "Cache store - redis or memcached"
+  type        = string
+  default     = "none"
+}

templates/terraform/environments/prod/main.tf

@@ -110,6 +110,15 @@ module "prod" {
   sendgrid_enabled = <%if eq (index .Params `sendgridApiKey`) "" %>false<% else %>true<% end %>
   sendgrid_api_key_secret_name = "${local.project}-sendgrid-<% index .Params `randomSeed` %>"
 
+  # Cache configuration
+  ## you may define "redis" or "memcached" as your cache store. If you define "none", there will be no cache service launched.
+  ## Check https://docs.aws.amazon.com/AmazonElastiCache/latest/mem-ug/SelectEngine.html to compare redis or memcached.
+  cache_store = "<% index .Params `cacheStore` %>"
+
+  ## See how to define node and instance type: https://docs.aws.amazon.com/AmazonElastiCache/latest/mem-ug/nodes-select-size.html
+  cache_cluster_size  = 1
+  cache_instance_type = "cache.r6g.large"
+
   # Roles configuration
   roles = [
     {

templates/terraform/environments/stage/main.tf

@@ -130,6 +130,15 @@ module "stage" {
   sendgrid_enabled = <%if eq (index .Params `sendgridApiKey`) "" %>false<% else %>true<% end %>
   sendgrid_api_key_secret_name = "${local.project}-sendgrid-<% index .Params `randomSeed` %>"
 
+  # Cache configuration
+  ## you may define "redis" or "memcached" as your cache store. If you define "none", there will be no cache service launched.
+  ## Check https://docs.aws.amazon.com/AmazonElastiCache/latest/mem-ug/SelectEngine.html to compare redis or memcached.
+  cache_store = "<% index .Params `cacheStore` %>"
+
+  ## See how to define node and instance type: https://docs.aws.amazon.com/AmazonElastiCache/latest/mem-ug/nodes-select-size.html
+  cache_cluster_size  = 1
+  cache_instance_type = "cache.t2.micro"
+
   # Roles configuration
   roles = [
     {

templates/terraform/modules/environment/main.tf

@@ -179,6 +179,27 @@ module "user_access" {
   users = local.user_access_users
 }
 
+module "cache" {
+  count = var.cache_store == "none" ? 0 : 1
+
+  source  = "commitdev/zero/aws//modules/cache"
+  version = "0.1.16"
+
+  project     = var.project
+  environment = var.environment
+
+  cache_store = var.cache_store
+
+  vpc_id     = module.vpc.vpc_id
+  subnet_ids = module.vpc.private_subnets
+
+  cluster_size       = var.cache_cluster_size
+  instance_type      = var.cache_instance_type
+  availability_zones = module.vpc.azs
+  security_groups    = [module.eks.worker_security_group_id]
+
+  redis_transit_encryption_enabled = var.cache_redis_transit_encryption_enabled
+}
 
 output "s3_hosting" {
   description = "used by access policy for s3 hosting bucket"

templates/terraform/modules/environment/variables.tf

@@ -181,3 +181,27 @@ variable "ci_user_name" {
   type        = string
   description = "CI user name" 
 }
+
+variable "cache_instance_type" {
+  type        = string
+  default     = "cache.t2.micro"
+  description = "Elastic cache instance type"
+}
+
+variable "cache_cluster_size" {
+  type        = number
+  default     = 1
+  description = "Number of nodes in cluster"
+}
+
+variable "cache_store" {
+  type        = string
+  default     = "none"
+  description = "Cache store - redis or memcached"
+}
+
+variable "cache_redis_transit_encryption_enabled" {
+  description = "Enable TLS for redis traffic. When this is enabled, your application needs to handle TLS connection. Note: redis-cli can not handle TLS."
+  type        = bool
+  default     = true
+}

zero-module.yml

@@ -66,6 +66,12 @@ parameters:
     options:
       - "postgres"
       - "mysql"
+  - field: cacheStore
+    label: "Cache store to use (default: no cache)"
+    options:
+      - "none"
+      - "redis"
+      - "memcached"
   - field: loggingType
     label: Application logging to configure. Cloudwatch is cheaper with a more limited feature set. Elasticsearch + Kibana will set up more infrastructure but enable a much richer logging search and visualization experience.
     options: