modules/backend/variables.tf

/**
 * Copyright 2024 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

variable "project_id" {
  description = "The project to deploy load balancer backend resources."
  type        = string
}

variable "region" {
  description = "The region where the load balancer backend service will be created"
  type        = string
}

variable "name" {
  description = "Name for the load balancer backend service."
  type        = string
}

variable "host_path_mappings" {
  description = "The list of host/path for which traffic should be sent to this backend service"
  type = list(object({
    host = string
    path = string
  }))
  default = [{ host : "*", path : "/*" }]
}

variable "serverless_neg_backends" {
  description = "The list of serverless backends which serves the traffic. A region can have only one serverless backend."
  type = list(object({
    region          = string
    type            = string // cloud-run, cloud-function, and app-engine
    service_name    = string
    service_version = optional(string)
    capacity_scaler = optional(number, 1.0)
  }))
  default = []

  validation {
    condition     = length(distinct([for backend in var.serverless_neg_backends : backend.region])) == length(var.serverless_neg_backends)
    error_message = "The 'region' within each 'serverless_neg_backends' block must be unique."
  }
}

variable "groups" {
  description = "The list of backend instance group which serves the traffic."
  type = list(object({
    group       = string
    description = optional(string)

    balancing_mode               = optional(string)
    capacity_scaler              = optional(number, 1.0)
    max_connections              = optional(number)
    max_connections_per_instance = optional(number)
    max_connections_per_endpoint = optional(number)
    max_rate                     = optional(number)
    max_rate_per_instance        = optional(number)
    max_rate_per_endpoint        = optional(number)
    max_utilization              = optional(number)
  }))
  default = []
}

variable "load_balancing_scheme" {
  description = "Load balancing scheme type (EXTERNAL for classic external load balancer, EXTERNAL_MANAGED for Envoy-based load balancer, and INTERNAL_MANAGED for internal load balancer)"
  type        = string
  default     = "EXTERNAL_MANAGED"
}

variable "protocol" {
  description = "The protocol this BackendService uses to communicate with backends."
  type        = string
  default     = "HTTP"
}

variable "port_name" {
  description = "Name of backend port. The same name should appear in the instance groups referenced by this service. Required when the load balancing scheme is EXTERNAL."
  type        = string
  default     = "http"
}

variable "description" {
  description = "Description of the backend service."
  type        = string
  default     = null
}

variable "health_check" {
  description = "Input for creating HttpHealthCheck or HttpsHealthCheck resource for health checking this BackendService. A health check must be specified unless the backend service uses an internet or serverless NEG as a backend."
  type = object({
    host                = optional(string, null)
    request_path        = optional(string, null)
    request             = optional(string, null)
    response            = optional(string, null)
    port                = optional(number, null)
    port_name           = optional(string, null)
    proxy_header        = optional(string, null)
    port_specification  = optional(string, null)
    protocol            = optional(string, null)
    check_interval_sec  = optional(number, 10)
    timeout_sec         = optional(number, 10)
    healthy_threshold   = optional(number, 2)
    unhealthy_threshold = optional(number, 2)
    logging             = optional(bool, true)
  })
  default = null
}

variable "firewall_networks" {
  description = "Names of the networks to create firewall rules in"
  type        = list(string)
  default     = ["default"]
}

variable "firewall_projects" {
  description = "Names of the projects to create firewall rules in"
  type        = list(string)
  default     = ["default"]
}

variable "target_tags" {
  description = "List of target tags for health check firewall rule. Exactly one of target_tags or target_service_accounts should be specified."
  type        = list(string)
  default     = []
}

variable "target_service_accounts" {
  description = "List of target service accounts for health check firewall rule. Exactly one of target_tags or target_service_accounts should be specified."
  type        = list(string)
  default     = []
}

variable "firewall_source_ranges" {
  description = "Source ranges for regional Application Load Balancer's proxies. This should be set to ip_cidr_range of your REGIONAL_MANAGED_PROXY subnet."
  type        = list(string)
  default     = ["10.129.0.0/23"]
}

variable "connection_draining_timeout_sec" {
  description = "Time for which instance will be drained (not accept new connections, but still work to finish started)."
  type        = number
  default     = null
}

variable "enable_cdn" {
  description = "Enable Cloud CDN for this BackendService."
  type        = bool
  default     = false
}

variable "session_affinity" {
  description = "Type of session affinity to use. Possible values are: NONE, CLIENT_IP, CLIENT_IP_PORT_PROTO, CLIENT_IP_PROTO, GENERATED_COOKIE, HEADER_FIELD, HTTP_COOKIE, STRONG_COOKIE_AFFINITY."
  type        = string
  default     = null
}

variable "affinity_cookie_ttl_sec" {
  description = "Lifetime of cookies in seconds if session_affinity is GENERATED_COOKIE."
  type        = number
  default     = null
}

variable "locality_lb_policy" {
  description = "The load balancing algorithm used within the scope of the locality."
  type        = string
  default     = null
}

variable "security_policy" {
  description = "The resource URL for the security policy to associate with the backend service"
  type        = string
  default     = null
}

variable "timeout_sec" {
  description = "This has different meaning for different type of load balancing. Please refer https://cloud.google.com/load-balancing/docs/backend-service#timeout-setting"
  type        = number
  default     = null
}