🏗️ Advanced Patterns & Import

Dynamic blocks, moved block, import, lifecycle hooks, refactoring

Terraform Associate · TF-Associate · ⏱️ 20 min · ❓ 4 savol

🔄 Dynamic Blocks

Takrorlanuvchi nested block larni dinamik yaratish. `dynamic "ingress"` va `content` block. `for_each` bilan combine qilinadi. Masalan: security group rules listdan. Complex resource (ALB listener rules, IAM policy statements) uchun juda foydali.

📦 moved Block (Terraform 1.1+)

Resursni rename yoki module ga ko'chirganda state muammosini hal qiladi. `terraform state mv` o'rniga declarative. `moved { from = aws_instance.old to = aws_instance.new }`. Plan da ko'rsatiladi, no destroy+recreate. Module restructuring da zarur.

📥 import Block (Terraform 1.5+)

Mavjud resursni Terraform boshqaruviga olish — declarative. `import { to = aws_s3_bucket.main id = "my-bucket-name" }`. `terraform plan -generate-config-out=generated.tf` — .tf ham generatsiya qiladi. Eski: `terraform import` buyruq (hali ishlaydi).

🔧 Lifecycle Hooks

`lifecycle` block ichida: create_before_destroy — yangi resurs avval, keyin eski o'chiriladi (zero downtime). prevent_destroy — destroy dan himoya. ignore_changes — qaysi atributlar o'zgarsada Terraform e'tibor bermasin (masalan, ami). replace_triggered_by — boshqa resurs o'zgarganda recreate.

💡 Asosiy nuqtalar

dynamic block: takrorlanuvchi nested block larni for_each bilan
moved block: rename/refactor, no destroy
import block (1.5+): declarative import
create_before_destroy: zero downtime replace
ignore_changes: drift qabul qilish
prevent_destroy: production resursni himoya

📋 Kod misoli

# Dynamic blocks: security group rules
variable "ingress_rules" {
  default = [
    { port = 80,  cidr = "0.0.0.0/0" },
    { port = 443, cidr = "0.0.0.0/0" },
    { port = 22,  cidr = "10.0.0.0/8" }
  ]
}

resource "aws_security_group" "web" {
  dynamic "ingress" {
    for_each = var.ingress_rules
    content {
      from_port   = ingress.value.port
      to_port     = ingress.value.port
      protocol    = "tcp"
      cidr_blocks = [ingress.value.cidr]
    }
  }
}

# moved block: aws_instance.web -> module.compute.aws_instance.web
moved {
  from = aws_instance.web
  to   = module.compute.aws_instance.web
}

# import block (Terraform 1.5+)
import {
  to = aws_s3_bucket.existing
  id = "my-existing-bucket"
}

# lifecycle
resource "aws_instance" "web" {
  ami           = data.aws_ami.latest.id
  instance_type = "t3.micro"
  lifecycle {
    create_before_destroy = true
    prevent_destroy       = true
    ignore_changes        = [ami]
  }
}

🎯 Imtihon maslahatlari

dynamic block — faqat resource ning nested block lari uchun (top-level resource emas)
moved block vs terraform state mv: moved = declarative (kodni review qilish mumkin), state mv = imperative
import block (1.5+) + generate-config-out → .tf fayl avtomatik yaratiladi
ignore_changes = ["ami"] — instance ami o'zgarsa Terraform e'tibor bermaydi (ASG launch template pattern)
replace_triggered_by — dependency chain da rebuild trigger

⚠️ Ko'p adashadigan

dynamic block ni for_each meta-argument bilan aralashtirib yuborish — dynamic=nested block iterator, for_each=resource iterator
moved block destroy+recreate qiladi deb o'ylash — moved faqat state mapping o'zgartiradi
import block .tf faylni ham yaratadi deb o'ylash — faqat -generate-config-out bilan

🧠 Eslab qolish: "DMIL" = Dynamic (blocks), Moved (refactor), Import (existing), Lifecycle (hooks) — Terraform 4 advanced pattern