flupdt/cli.py

@@ -7,5 +7,8 @@ def parse_inputs():
     parser.add_argument(
         "flake_path", metavar="flake-path", help="path to flake to evaluate"
     )
+    parser.add_argument(
+        "--keep-hydra", action="store_true",help="allow evaluating Hydra jobs"
+    )
     args = parser.parse_args()
     return args

flupdt/common.py

@@ -21,7 +21,7 @@ def configure_logger(level: str = "INFO") -> None:
     )
 
 
-def bash_wrapper(command: str, path: str = ".") -> tuple[str, int]:
+def bash_wrapper(command: str, path: str = ".") -> tuple[str, str, int]:
     """Execute a bash command and capture the output.
 
     Args:
@@ -34,6 +34,6 @@ def bash_wrapper(command: str, path: str = ".") -> tuple[str, int]:
     """
     # This is a acceptable risk
     process = Popen(command.split(), stdout=PIPE, stderr=PIPE, cwd=path)  # noqa: S603
-    output, _ = process.communicate()
+    output, error = process.communicate()
 
-    return output.decode(), process.returncode
+    return output.decode(), error.decode(), process.returncode

flupdt/flake_eval.py

@@ -0,0 +1,25 @@
+#!/usr/bin/env python3
+
+import logging
+from typing import Optional
+from flupdt.common import bash_wrapper
+import re
+
+drv_re = re.compile(r'.*(/nix/store/.*\.drv).*')
+
+def evaluate_output(path:str, output: str) -> Optional[str]:
+    logging.info(f"evaluating {output}")
+    out = bash_wrapper(f"nix eval {path}#{output}")
+    logging.debug(out[0])
+    logging.debug(out[1])
+    logging.debug(out[2])
+    if out[2] != 0:
+        logging.warning(f"output {output} did not evaluate correctly")
+        return None
+    else:
+        drv_match = drv_re.match(out[0])
+        if drv_match is None:
+            out_msg = "derivation succeeded but output derivation does not contain a derivation"
+            raise RuntimeError(out_msg)
+        drv = drv_match.group(1)
+        logging.debug(f"derivation evaluated to {drv}")

flupdt/flake_show.py

@@ -3,9 +3,16 @@
 import json
 from flupdt.common import bash_wrapper
 import shutil
+import logging
+import re
+
+output_regexes = [
+    re.compile(r'checking derivation (.*)...'),
+    re.compile(r'checking NixOS configuration \'(nixosConfigurations.*)\'\.\.\.')
+]
 
 
-def traverse_json_base(json_dict: dict, path: list[str]):
+def traverse_json_base(json_dict: dict, path: list[str]) -> list[str]:
     final_paths = []
     for key, value in json_dict.items():
         if isinstance(value, dict):
@@ -14,21 +21,46 @@ def traverse_json_base(json_dict: dict, path: list[str]):
                 "nixos-configuration",
                 "derivation",
             ]:
-                final_paths += [".".join(path + [key])]
+                output = ".".join(path + [key])
+                final_paths += [output]
             else:
                 final_paths += traverse_json_base(value, path + [key])
     return final_paths
 
 
-def traverse_json(json_dict: dict):
+def traverse_json(json_dict: dict) -> list[str]:
     return traverse_json_base(json_dict, [])
 
-
-def get_derivations(path_to_flake: str):
-    nix_path = shutil.which("nix")
-    flake_show = bash_wrapper(f"{nix_path} flake show --json", path=path_to_flake)
-    if flake_show[1] != 0:
-        raise RuntimeError("flake show returned non-zero exit code")
-    flake_show_json = json.loads(flake_show[0])
-    derivations = traverse_json(flake_show_json)
+def get_derivations_from_check(nix_path:str,path_to_flake:str)-> list[str]:
+    flake_check = bash_wrapper(f"{nix_path} flake check --verbose --keep-going", path=path_to_flake)
+    if flake_check[2] != 0:
+        logging.warn("nix flake check returned non-zero exit code, collecting all available outputs")
+    error_out = flake_check[1].split('\n')
+    possible_outputs = filter(lambda s: s.startswith("checking"), error_out)
+    derivations = []
+    for output in possible_outputs:
+        for r in output_regexes:
+            logging.debug(f"{output} {r.pattern}")
+            match = r.match(output)
+            if match is not None:
+                logging.debug(match.groups())
+                derivations += [match.groups()[0]]
+    return derivations
+
+def get_derivations(path_to_flake: str) -> list[str]:
+    nix_path = shutil.which("nix")
+    derivations = []
+    if nix_path is None:
+        raise RuntimeError("nix is not available in the PATH, please verify that it is installed")
+    flake_show = bash_wrapper(f"{nix_path} flake show --json", path=path_to_flake)
+    if flake_show[2] != 0:
+        logging.error("flake show returned non-zero exit code")
+        logging.warn("falling back to full evaluation via nix flake check")
+        derivations =  get_derivations_from_check(nix_path, path_to_flake)
+    else:
+        flake_show_json = json.loads(flake_show[0])
+        derivations = traverse_json(flake_show_json)
+    for i in range(len(derivations)):
+        if derivations[i].startswith("nixosConfigurations"):
+             derivations[i] += ".config.system.build.toplevel"
     return derivations

flupdt/main.py

@@ -2,11 +2,21 @@
 
 from flupdt.flake_show import get_derivations
 from flupdt.cli import parse_inputs
-
+from flupdt.flake_eval import evaluate_output
+from flupdt.common import configure_logger
+import logging
 
 def main():
+    configure_logger("INFO")
     args = parse_inputs()
-    print(get_derivations(args.flake_path))
+    flake_path = args.flake_path
+    derivations = get_derivations(flake_path)
+    if not args.keep_hydra and len(list(filter(lambda s: s.startswith("hydraJobs"), derivations))) > 0:
+        logging.info("--keep-hydra flag is not specified, removing Hydra jobs")
+        derivations = filter(lambda s: not s.startswith("hydraJobs"), derivations)
+    logging.info(f"derivations: {list(derivations)}")
+    for d in derivations:
+        evaluate_output(flake_path, d)
 
 
 if __name__ == "__main__":