feat: initial commit of application storage composition.

terraform/aws/modules/composition/application-storage/data.tf

@@ -0,0 +1,43 @@
+# Data sources for Aurora composition module
+
+# Current AWS region
+data "aws_region" "current" {}
+
+# Current AWS caller identity (account ID)
+data "aws_caller_identity" "current" {}
+
+# VPC information for validation and reference
+data "aws_vpc" "selected" {
+  id = var.vpc_id
+}
+
+# Subnet information for validation
+data "aws_subnets" "database" {
+  filter {
+    name   = "subnet-id"
+    values = var.database_subnet_ids
+  }
+}
+
+# Get subnet details for each database subnet
+data "aws_subnet" "database" {
+  for_each = toset(var.database_subnet_ids)
+  id       = each.value
+}
+
+# Application security group information for validation
+data "aws_security_group" "application" {
+  id = var.application_security_group_id
+}
+
+# Get available Aurora PostgreSQL engine versions (for validation)
+data "aws_rds_engine_versions" "postgresql" {
+  engine         = "aurora-postgresql"
+  preferred_versions = [var.engine_version]
+}
+
+# Default KMS key for RDS (if no custom key provided)
+data "aws_kms_key" "rds_default" {
+  count  = var.kms_key_id == null ? 1 : 0
+  key_id = "alias/aws/rds"
+}

terraform/aws/modules/composition/application-storage/locals.tf

@@ -0,0 +1,48 @@
+# Local values for naming and tagging
+locals {
+  # Naming convention following the established pattern
+  name_prefix = "${var.environment}-${var.project_name}-app-storage"
+
+  # Instance class mapping by environment
+  instance_class_map = {
+    dev     = "db.r6g.large"    # 2 vCPUs, 16 GB RAM - suitable for development
+    integ   = "db.r6g.xlarge"   # 4 vCPUs, 32 GB RAM - suitable for integration testing
+    prod    = "db.r6g.xlarge"   # 4 vCPUs, 32 GB RAM - production workload
+    sandbox = "db.r6g.large"    # 2 vCPUs, 16 GB RAM - sandbox environment
+    sbx     = "db.r6g.large"    # 2 vCPUs, 16 GB RAM - sandbox environment (short form)
+  }
+
+  # Select instance class based on environment or override
+  instance_class = coalesce(
+    var.instance_class_override,
+    lookup(local.instance_class_map, var.environment, "db.r6g.large")
+  )
+
+  # Common tags applied to all resources - following established pattern
+  common_tags = merge(var.tags, {
+    Environment = var.environment
+    Service     = "application-storage"
+    ManagedBy   = "Terraform"
+    Module      = "composition/application-storage"
+  })
+
+  # Environment-specific configuration flags
+  is_production = contains(["prod", "production"], var.environment)
+  is_sandbox    = contains(["sandbox", "sbx"], var.environment)
+  is_dev        = contains(["dev", "development"], var.environment)
+
+  # Dynamic configuration based on environment
+  enhanced_monitoring_enabled = local.is_production ? true : var.monitoring_interval > 0
+  performance_insights_enabled = local.is_production ? true : var.performance_insights_enabled
+  deletion_protection_enabled = local.is_production ? true : var.deletion_protection
+
+  # Backup configuration adjustments
+  backup_retention_days = local.is_production ? max(var.backup_retention_period, 14) : var.backup_retention_period
+
+  # RDS Proxy configuration
+  rds_proxy_enabled = var.enable_rds_proxy
+
+  # Environment-specific RDS Proxy defaults
+  proxy_max_connections = local.is_production ? 100 : 75
+  proxy_max_idle_connections = local.is_production ? 25 : 50
+}