Basic State Commands

เรียน terraform state list, show, output, graph — commands ที่ใช้ดู state ทั่วไป

terraform state list

แสดง resource ทั้งหมดใน state:

$ terraform state list
aws_s3_bucket.data
aws_s3_bucket.logs
aws_instance.web
aws_security_group.web
data.aws_ami.ubuntu
module.network.aws_vpc.main
module.network.aws_subnet.public[0]
module.network.aws_subnet.public[1]

Filter by Pattern

# แสดงเฉพาะ S3 buckets
terraform state list "*s3*"

# แสดงเฉพาะ resource ใน module
terraform state list "module.network.*"

Count Resources

terraform state list | wc -l

terraform state show

ดูรายละเอียดของ resource:

$ terraform state show aws_s3_bucket.data
# aws_s3_bucket.data:
resource "aws_s3_bucket" "data" {
    arn                         = "arn:aws:s3:::my-data-bucket"
    bucket                      = "my-data-bucket"
    bucket_domain_name          = "my-data-bucket.s3.amazonaws.com"
    bucket_regional_domain_name = "my-data-bucket.s3.ap-southeast-1.amazonaws.com"
    force_destroy               = false
    hosted_zone_id              = "Z3O0J2DXBE1FTB"
    id                          = "my-data-bucket"
    region                      = "ap-southeast-1"
    request_payer               = "BucketOwner"
    tags                        = {
        "Environment" = "prod"
    }
    tags_all                    = {
        "Environment" = "prod"
    }
}

ใช้ดู:

• ARN, ID ของ resource
• Attribute ทั้งหมด (รวม computed)
• Current state ตาม Terraform's view

ดู Module Resource

terraform state show 'module.network.aws_vpc.main'

ดูใน count / for_each

terraform state show 'aws_subnet.public[0]'
terraform state show 'aws_iam_user.team["alice"]'

terraform output

ดู output values:

# ดูทั้งหมด
$ terraform output
bucket_name = "my-data-bucket"
vpc_id      = "vpc-12345"

# ดูตัวเดียว
$ terraform output bucket_name
"my-data-bucket"

# Raw (no quotes — เหมาะ shell)
$ terraform output -raw bucket_name
my-data-bucket

# JSON
$ terraform output -json
{
  "bucket_name": {
    "value": "my-data-bucket",
    "type": "string"
  }
}

Use Cases

# Pipe ไป ssh
ssh ec2-user@$(terraform output -raw web_public_ip)

# Save to file
terraform output -json > outputs.json

# Pass to script
DATABASE_URL=$(terraform output -raw db_url) ./deploy.sh

terraform graph

Generate dependency graph:

terraform graph

Output (DOT format):

digraph {
  compound = "true"
  newrank = "true"
  subgraph "root" {
    "[root] aws_instance.web (expand)" -> "[root] aws_subnet.public (expand)"
    "[root] aws_subnet.public (expand)" -> "[root] aws_vpc.main (expand)"
  }
}

Render เป็น Image

# Install graphviz
brew install graphviz

# Generate PNG
terraform graph | dot -Tpng > graph.png

# SVG
terraform graph | dot -Tsvg > graph.svg

Filter

# Plan graph (เฉพาะ resource ที่จะเปลี่ยน)
terraform graph -type=plan

# Apply graph
terraform graph -type=apply

# Validate graph
terraform graph -type=validate

terraform refresh

อัปเดต state ให้ตรงกับ reality:

terraform refresh

Deprecated in 0.15+

terraform refresh ยังใช้ได้ แต่แนะนำใช้:

terraform apply -refresh-only

จะแสดง diff ก่อน + ถาม confirm

terraform providers

แสดง providers ที่ใช้:

$ terraform providers
.
├── provider[registry.terraform.io/hashicorp/aws] ~> 5.0
├── provider[registry.terraform.io/hashicorp/random] ~> 3.5
└── module.network
    └── provider[registry.terraform.io/hashicorp/aws] ~> 5.0

List Versions

terraform providers schema -json > schema.json

Lock Cross-Platform

terraform providers lock \
  -platform=linux_amd64 \
  -platform=darwin_arm64 \
  -platform=darwin_amd64 \
  -platform=windows_amd64

→ Update .terraform.lock.hcl ให้รองรับทุก platform

terraform version

$ terraform version
Terraform v1.9.8
on darwin_arm64
+ provider registry.terraform.io/hashicorp/aws v5.70.0

# JSON
terraform version -json

terraform console

REPL สำหรับทดสอบ expression:

$ terraform console

> upper("hello")
"HELLO"

> length([1, 2, 3])
3

> aws_s3_bucket.data.arn
"arn:aws:s3:::my-data-bucket"

> [for i in range(3) : "host-${i}"]
[
  "host-0",
  "host-1",
  "host-2",
]

ใช้ทดสอบ HCL expression / function โดยไม่ต้อง apply

ออก: Ctrl+D หรือ exit

terraform fmt + validate (recap)

# Format
terraform fmt -recursive

# Format check (CI)
terraform fmt -check -recursive

# Validate
terraform validate

terraform get

Download modules (ทำใน terraform init แล้ว — ใช้แยกได้):

terraform get
terraform get -update    # update modules

ตัวอย่าง: Quick Diagnostic

# 1. ดู resource ที่ manage
terraform state list

# 2. ดู resource ที่น่าสงสัย
terraform state show 'aws_instance.web'

# 3. ตรวจ drift
terraform plan -refresh-only

# 4. ดู output
terraform output

# 5. ดู provider
terraform providers

รวม commands ใน script

scripts/inspect.sh

#!/bin/bash
set -e

echo "=== State Inspection ==="
echo ""
echo "Total resources:"
terraform state list | wc -l

echo ""
echo "Resources by type:"
terraform state list | sed 's/\[.*\]//' | awk -F'.' '{print $1}' | sort | uniq -c

echo ""
echo "Outputs:"
terraform output

echo ""
echo "Drift check:"
terraform plan -refresh-only -no-color | grep -E '^\s*~|\s*-' | head -20

สรุป

Command	หน้าที่
state list	List resources ใน state
state show	ดู attributes ของ resource
output	ดู output values
graph	Dependency graph (DOT format)
refresh (deprecated)	Update state จาก reality
providers	List providers ที่ใช้
version	Version ของ Terraform + providers
console	REPL ทดสอบ expression

ต่อไป → Modify State