tf-attr-editor - Edit attributes within a list of HCL objects

tf-attr-editor.py

#!/usr/bin/env python3
"""
tf-attr-editor - Edit attributes within a list of HCL objects
"""

import argparse
import subprocess
import sys
from pathlib import Path

import hcl2

__version__ = "0.4.3-debug"


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("-file", required=True)
    parser.add_argument("-path", required=True)
    parser.add_argument("-pos", type=int, required=True)
    parser.add_argument("-field", required=True)
    parser.add_argument("-value", required=True)
    parser.add_argument("--debug", action="store_true", help="Print parsed HCL structure")
    parser.add_argument("--version", action="version", version=f"%(prog)s {__version__}")

    args = parser.parse_args()

    file_path = Path(args.file)
    if not file_path.exists():
        print(f"Error: file {file_path} does not exist", file=sys.stderr)
        sys.exit(1)

    # Parse HCL
    try:
        with open(file_path, "r", encoding="utf-8") as f:
            data = hcl2.load(f)
    except Exception as e:
        print(f"Error: invalid HCL: {e}", file=sys.stderr)
        sys.exit(1)

    if args.debug:
        print("=== DEBUG: Parsed HCL structure ===")
        import pprint
        pprint.pprint(data, indent=2)
        print("=================================")

    # Try to find the list
    target_list = None

    # Case 1: Top-level list
    if args.path in data and isinstance(data[args.path], list):
        target_list = data[args.path]

    # Case 2: locals.my_list
    elif args.path.startswith("locals."):
        list_name = args.path.split(".")[-1]
        for loc in data.get("locals", []):
            if isinstance(loc, dict) and list_name in loc and isinstance(loc[list_name], list):
                target_list = loc[list_name]
                break

    # Case 3: Just "my_list" inside locals
    elif args.path == "my_list":
        for loc in data.get("locals", []):
            if isinstance(loc, dict) and "my_list" in loc and isinstance(loc["my_list"], list):
                target_list = loc["my_list"]
                break

    if target_list is None:
        print(f"Error: list '{args.path}' not found", file=sys.stderr)
        print("Tip: Run with --debug to see the parsed structure", file=sys.stderr)
        sys.exit(1)

    # Rest of the logic (unchanged)
    if not isinstance(target_list, list) or args.pos < 0 or args.pos >= len(target_list):
        print(f"Error: position {args.pos} is out of bounds", file=sys.stderr)
        sys.exit(1)

    target_obj = target_list[args.pos]
    if not isinstance(target_obj, dict):
        print(f"Error: element at position {args.pos} is not an object", file=sys.stderr)
        sys.exit(1)

    if args.field in target_obj:
        print(f"Error: field '{args.field}' already exists", file=sys.stderr)
        sys.exit(1)

    target_obj[args.field] = args.value

    try:
        with open(file_path, "w", encoding="utf-8") as f:
            hcl2.dump(data, f)
    except Exception as e:
        print(f"Error: failed to write file: {e}", file=sys.stderr)
        sys.exit(1)

    try:
        subprocess.run(["terraform", "fmt", "-write=true", str(file_path)], check=True, capture_output=True)
    except Exception:
        pass

    print(f"✅ Successfully added '{args.field}' to object at position {args.pos} in {args.path}")


if __name__ == "__main__":
    main()