Terraform state moving script

README.md

Terraform state moving script

This script will use a mapping of old and new Terraform resources path to move from an exisiting state to a new state. This is handy when restructuring a Terraform project.

Steps before running this script:

• In exisiting project:
  • Make sure you have intiiated with the correct state backend (if you are using different state backends)
  • Run terraform state list and grab the paths. you would need to filter between resource paths and other paths like data blocks
• In new structure:
  • Run terraform init
  • Run terraform plan
  • Copy all the new resources paths that would be created (starts with the "+")
• Map between exisiting project paths and new project paths
• Add the mapping to this script

terraform_state_moving_script.py

"""
Requirements: python sh

# Terraform state moving script
This script will use a mapping of old and new Terraform resources path to move from
an exisiting state to a new state. This is handy when restructuring a Terraform project.

Steps before running this script:
    - In exisiting project:
        - Make sure you have intiiated with the correct state backend (if you are using different state backends)
        - Run `terraform state list` and grab the paths. you would need to filter between resource paths and other paths like data blocks
    - In new structure:
        - Run `terraform init`
        - Run `terraform plan`
        - Copy all the new resources paths that would be created (starts with the "+")
    - Map between exisiting project paths and new project paths
    - Add the mapping to this script
"""

from tempfile import NamedTemporaryFile
from sh import terraform

# Map old path to new path
mapping = [
    ('<old target path>', '<new target path>'),
]

# Get the JSON data returned by the `terraform state pull` command
# Represting the current project state
full_state_data = terraform.state('pull')

# Create a temporary file with the current state
source_temp_file = NamedTemporaryFile(mode='w')
source_temp_file.file.write(str(full_state_data))
source_temp_file.file.close()

# Create an empty temporary file for the new state
target_temp_file = NamedTemporaryFile()

# Loop through the resource mapping and move one by one
for source, target in mapping:
    print(source, target)

    # Run `terraform state mv`. moving from current state temp file to new state temp file
    resp = terraform.state(
        'mv',
        '-state-out',
        target_temp_file.name,
        '-state',
        source_temp_file.name,
        source,
        target,
    )

    print(resp)
    print('-' * 100)

# Print the copy command form the temp file to whereever you want the new state file to be in
print('cp', target_temp_file.name, 'terraform.tfstate')