Despliegue desde CI sin secretos (federación OIDC)

# Despliegue desde CI sin secretos — GCP
#
# Workload Identity Pool + provider OIDC de GitHub con una condición CEL sobre
# IDs inmutables, y una service account de despliegue que solo puede
# impersonar el principalSet de ese repositorio.

locals {
  # Las cuatro APIs que pide la guía de Google para pipelines.
  apis = ["iam.googleapis.com", "cloudresourcemanager.googleapis.com", "iamcredentials.googleapis.com", "sts.googleapis.com"]

  envs_cel = join(", ", [for e in sort(tolist(var.environments)) : "'${e}'"])

  # Sin condición, cualquier repo de GitHub podría obtener tokens: el issuer es compartido.
  attribute_condition = "assertion.repository_owner_id == '${var.github.owner_id}' && assertion.repository_id == '${var.github.repository_id}' && assertion.environment in [${local.envs_cel}]"

  attribute_mapping = {
    "google.subject"                = "assertion.sub"
    "attribute.repository_id"       = "assertion.repository_id"
    "attribute.repository_owner_id" = "assertion.repository_owner_id"
    "attribute.environment"         = "assertion.environment"
  }
}

resource "google_project_service" "required" {
  for_each = toset(local.apis)

  project            = var.project_id
  service            = each.value
  disable_on_destroy = false
}

resource "google_iam_workload_identity_pool" "github" {
  project                   = var.project_id
  workload_identity_pool_id = var.pool_id
  display_name              = "GitHub Actions"
  description               = "Tokens OIDC de GitHub Actions"

  depends_on = [google_project_service.required]
}

resource "google_iam_workload_identity_pool_provider" "github" {
  #checkov:skip=CKV_GCP_125:El check solo reconoce condiciones sobre assertion.sub con nombres; esta condición usa repository_owner_id y repository_id (inmutables), que es lo que recomienda Google.
  project                            = var.project_id
  workload_identity_pool_id          = google_iam_workload_identity_pool.github.workload_identity_pool_id
  workload_identity_pool_provider_id = "github-oidc"
  display_name                       = "GitHub OIDC"

  attribute_mapping   = local.attribute_mapping
  attribute_condition = local.attribute_condition

  oidc {
    issuer_uri = "https://token.actions.githubusercontent.com"
  }
}

resource "google_service_account" "deploy" {
  project      = var.project_id
  account_id   = "gha-deploy"
  display_name = "GitHub Actions deploy"
}

# Solo el principalSet de este repositorio puede impersonar la SA.
resource "google_service_account_iam_member" "workload_identity_user" {
  service_account_id = google_service_account.deploy.name
  role               = "roles/iam.workloadIdentityUser"
  member             = "principalSet://iam.googleapis.com/${google_iam_workload_identity_pool.github.name}/attribute.repository_id/${var.github.repository_id}"
}

resource "google_project_iam_member" "deploy" {
  for_each = var.deploy_roles

  project = var.project_id
  role    = each.value
  member  = "serviceAccount:${google_service_account.deploy.email}"
}

variable "project_id" {
  description = "Proyecto donde viven el pool y la service account de despliegue."
  type        = string
}

variable "region" {
  description = "Región por defecto del provider."
  type        = string
  default     = "us-central1"
}

variable "pool_id" {
  description = "ID del workload identity pool (4-32, minúsculas). Un pool borrado bloquea su ID ~30 días (gotcha: pool-soft-delete-30-days)."
  type        = string
  default     = "github"

  validation {
    condition     = can(regex("^[a-z0-9-]{4,32}$", var.pool_id)) && !startswith(var.pool_id, "gcp-")
    error_message = "pool_id: 4-32 caracteres [a-z0-9-], sin el prefijo reservado gcp-."
  }
}

variable "github" {
  description = <<-EOT
    Repositorio que puede desplegar. En GCP la condición se arma sobre los IDs numéricos (inmutables), no sobre
    los nombres: un nombre de org o repo reciclado no hereda la confianza.
  EOT
  type = object({
    owner_id      = number
    repository_id = number
  })
}

variable "environments" {
  description = "Environments de GitHub que pueden desplegar."
  type        = set(string)
  default     = ["production"]

  validation {
    condition     = length(var.environments) >= 1 && alltrue([for e in var.environments : can(regex("^[A-Za-z0-9_.-]+$", e))])
    error_message = "environments: al menos uno, solo letras, números, '.', '_' o '-'."
  }
}

variable "deploy_roles" {
  description = "Roles de proyecto que necesita el despliegue (mínimo privilegio)."
  type        = set(string)

  validation {
    condition     = length(setintersection(var.deploy_roles, ["roles/owner", "roles/editor", "roles/iam.serviceAccountUser", "roles/iam.serviceAccountTokenCreator"])) == 0
    error_message = "deploy_roles: nada de owner/editor ni roles que permitan actuar como otras service accounts a nivel proyecto."
  }
}

output "workload_identity_provider" {
  description = "workload_identity_provider para google-github-actions/auth (usa el número de proyecto, no el ID)."
  value       = google_iam_workload_identity_pool_provider.github.name
}

output "service_account" {
  description = "service_account para google-github-actions/auth."
  value       = google_service_account.deploy.email
}

output "attribute_condition" {
  description = "Condición CEL que evalúa cada token."
  value       = local.attribute_condition
}

output "workflow_snippet" {
  description = "Fragmento mínimo del workflow."
  value       = <<-YAML
    permissions:
      id-token: write   # sin esto el job no puede pedir el token OIDC
      contents: read
    jobs:
      deploy:
        environment: ${sort(tolist(var.environments))[0]}
        steps:
          - uses: google-github-actions/auth@v3
            with:
              workload_identity_provider: ${google_iam_workload_identity_pool_provider.github.name}
              service_account: ${google_service_account.deploy.email}
  YAML
}

terraform {
  required_version = ">= 1.7.0"

  required_providers {
    google = {
      source  = "hashicorp/google"
      version = "~> 8.6"
    }
  }
}

provider "google" {
  project = var.project_id
  region  = var.region
}

# Despliegue desde CI sin secretos — AWS
#
# OIDC provider de GitHub (uno por cuenta) y un rol IAM cuya trust policy
# exige el audience de STS y un sub exacto por environment.

locals {
  github_host = "token.actions.githubusercontent.com"
  repo_path   = var.github.owner_id == null ? "${var.github.owner}/${var.github.repository}" : "${var.github.owner}@${var.github.owner_id}/${var.github.repository}@${var.github.repository_id}"

  # Si el job declara `environment:`, el sub es este (y no el de la rama).
  subjects = sort([for env in var.environments : "repo:${local.repo_path}:environment:${env}"])

  provider_arn = var.create_oidc_provider ? aws_iam_openid_connect_provider.github[0].arn : data.aws_iam_openid_connect_provider.github[0].arn

  trust_conditions = {
    StringEquals = {
      "${local.github_host}:aud" = "sts.amazonaws.com"
      "${local.github_host}:sub" = local.subjects
    }
  }
}

# Sin thumbprint_list: para GitHub, IAM valida el certificado contra su librería
# de CAs raíz y no usa el thumbprint (gotcha: thumbprint-not-used).
resource "aws_iam_openid_connect_provider" "github" {
  count = var.create_oidc_provider ? 1 : 0

  url            = "https://${local.github_host}"
  client_id_list = ["sts.amazonaws.com"]
}

data "aws_iam_openid_connect_provider" "github" {
  count = var.create_oidc_provider ? 0 : 1

  url = "https://${local.github_host}"
}

resource "aws_iam_role" "deploy" {
  name                 = var.name
  description          = "GitHub Actions ${local.repo_path} (${join(", ", local.subjects)})"
  max_session_duration = var.max_session_duration

  assume_role_policy = jsonencode({
    Version = "2012-10-17"
    Statement = [{
      Effect    = "Allow"
      Action    = "sts:AssumeRoleWithWebIdentity"
      Principal = { Federated = local.provider_arn }
      Condition = local.trust_conditions
    }]
  })
}

resource "aws_iam_role_policy_attachment" "deploy" {
  for_each = var.policy_arns

  role       = aws_iam_role.deploy.name
  policy_arn = each.value
}

variable "name" {
  description = "Nombre del rol de despliegue (ej. \"deploy-web\")."
  type        = string

  validation {
    condition     = can(regex("^[a-zA-Z0-9+=,.@_-]{3,64}$", var.name))
    error_message = "name: 3-64 caracteres válidos para un rol IAM."
  }
}

variable "region" {
  description = "Región del provider (IAM es global)."
  type        = string
  default     = "us-east-1"
}

variable "create_oidc_provider" {
  description = "Crear el OIDC provider de GitHub. Hay uno solo por URL y por cuenta: si ya existe, false y se referencia (gotcha: one-oidc-provider-per-account)."
  type        = bool
  default     = true
}

variable "github" {
  description = <<-EOT
    Repositorio que puede desplegar. owner_id y repository_id (numéricos) activan el formato inmutable del
    claim sub ("repo:owner@123/repo@456:..."), que GitHub usa por defecto en repos creados, renombrados o
    transferidos desde el 15/07/2026.
  EOT
  type = object({
    owner         = string
    repository    = string
    owner_id      = optional(number)
    repository_id = optional(number)
  })

  validation {
    condition     = (var.github.owner_id == null) == (var.github.repository_id == null)
    error_message = "github: owner_id y repository_id van juntos (formato inmutable) o ninguno de los dos."
  }
}

variable "environments" {
  description = "Environments de GitHub que pueden asumir el rol (match exacto con StringEquals)."
  type        = set(string)
  default     = ["production"]

  validation {
    condition     = length(var.environments) >= 1 && alltrue([for e in var.environments : !can(regex("[*?]", e))])
    error_message = "environments: al menos uno y sin comodines (el módulo usa StringEquals a propósito)."
  }
}

variable "policy_arns" {
  description = "Policies administradas que necesita el despliegue (mínimo privilegio)."
  type        = set(string)

  validation {
    condition     = !contains(var.policy_arns, "arn:aws:iam::aws:policy/AdministratorAccess")
    error_message = "policy_arns: AdministratorAccess no. Acotá los permisos a lo que despliega el pipeline."
  }
}

variable "max_session_duration" {
  description = "Duración máxima de la sesión en segundos (1 h a 12 h). Si el apply dura más que la sesión, falla a mitad de camino."
  type        = number
  default     = 3600

  validation {
    condition     = var.max_session_duration >= 3600 && var.max_session_duration <= 43200
    error_message = "max_session_duration: entre 3600 y 43200."
  }
}

variable "tags" {
  description = "Tags comunes."
  type        = map(string)
  default     = {}
}

output "role_arn" {
  description = "role-to-assume para aws-actions/configure-aws-credentials (no es un secreto)."
  value       = aws_iam_role.deploy.arn
}

output "subjects" {
  description = "Valores exactos de sub que acepta la trust policy."
  value       = local.subjects
}

output "workflow_snippet" {
  description = "Fragmento mínimo del workflow."
  value       = <<-YAML
    permissions:
      id-token: write   # sin esto el job no puede pedir el token OIDC
      contents: read
    jobs:
      deploy:
        environment: ${sort(tolist(var.environments))[0]}
        steps:
          - uses: aws-actions/configure-aws-credentials@v4
            with:
              role-to-assume: ${aws_iam_role.deploy.arn}
              aws-region: ${var.region}
  YAML
}

terraform {
  required_version = ">= 1.7.0"

  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 6.67"
    }
  }
}

provider "aws" {
  region = var.region

  default_tags {
    tags = var.tags
  }
}