54 lines
1.3 KiB
Python
54 lines
1.3 KiB
Python
#!/usr/bin/env python3
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"""
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Print the nixosConfigurations defined in flake.nix.
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Parses flake.nix directly (no `nix eval`, so it works without nix tooling
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and is fast). Brace-matches to find the closing `}` of nixosConfigurations
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so it handles nested attrsets correctly.
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"""
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import re
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import sys
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from pathlib import Path
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def list_hosts(flake_path: Path) -> list[str]:
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src = flake_path.read_text()
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m = re.search(r"nixosConfigurations\s*=\s*\{", src)
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if not m:
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return []
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# Brace-match to find the matching closing }.
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depth, i, close = 0, m.end() - 1, None
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while i < len(src):
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c = src[i]
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if c == "{":
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depth += 1
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elif c == "}":
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depth -= 1
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if depth == 0:
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close = i
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break
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i += 1
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block = src[m.end():close] if close is not None else ""
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return re.findall(
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r"^[ \t]*([A-Za-z_][\w-]*)\s*=\s*nixpkgs\.lib\.nixosSystem",
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block,
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re.M,
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)
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def main() -> int:
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flake = Path(sys.argv[1]) if len(sys.argv) > 1 else Path("flake.nix")
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if not flake.is_file():
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print(f"[-] not a file: {flake}", file=sys.stderr)
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return 1
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for name in list_hosts(flake):
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print(name)
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return 0
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if __name__ == "__main__":
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sys.exit(main())
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