soxoj/maigret · error · FileNotFoundError

Problem while attempting to access data file '{filename}'.

Error message

Problem while attempting to access data file '{filename}'.

What it means

load_from_file() raises FileNotFoundError('Problem while attempting to access data file ...') when open(filename) itself fails with FileNotFoundError — i.e. the path does not exist, a directory component is missing, or (on some platforms) the path is a directory. The original OSError is chained via 'from error', preserving the underlying cause. Because relative paths resolve against the process CWD, the most common cause is running the script from a different directory than the data file.

Source

Thrown at maigret/sites.py:595

        else:
            raise FileNotFoundError(
                f"Bad response while accessing " f"data file URL '{url}'."
            )

        return self.load_from_json(data)

    def load_from_file(self, filename: "str") -> "MaigretDatabase":
        try:
            with open(filename, "r", encoding="utf-8") as file:
                try:
                    data = json.load(file)
                except Exception as error:
                    raise ValueError(
                        f"Problem parsing json contents from "
                        f"file '{filename}':  {str(error)}."
                    )
        except FileNotFoundError as error:
            raise FileNotFoundError(
                f"Problem while attempting to access " f"data file '{filename}'."
            ) from error

        return self.load_from_json(data)

    def get_scan_stats(self, sites_dict):
        sites = sites_dict or self.sites_dict
        found_flags: Dict[str, int] = {}
        for _, s in sites.items():
            if "presense_flag" in s.stats:
                flag = s.stats["presense_flag"]
                found_flags[flag] = found_flags.get(flag, 0) + 1

        return found_flags

    def extract_ids_from_url(self, url: str) -> dict:
        results = {}
        for s in self._sites:

View on GitHub (pinned to 41674631a9)

Solutions

Print/verify the resolved path first: os.path.abspath(filename) and os.path.isfile(filename); fix the path or CWD.
Prefer absolute paths derived from your package location: pathlib.Path(__file__).parent / 'data.json'.
If the file is missing from a deployment, copy/vendor maigret's resources/data.json into your distribution or download it at startup.
For missing packaged assets in Docker/bundles, add the file to the image/build and reference it by absolute path.

Example fix

# before
db = MaigretDatabase().load_from_file('resources/data.json')  # breaks when CWD differs

# after
from pathlib import Path
DB_PATH = Path(__file__).resolve().parent / 'resources' / 'data.json'
assert DB_PATH.is_file(), f'missing maigret db at {DB_PATH}'
db = MaigretDatabase().load_from_file(str(DB_PATH))

Defensive patterns

Strategy: validation

Validate before calling

import os

path = os.path.abspath('resources/data.json')
if not os.path.isfile(path):
    raise SystemExit(f'maigret data file not found at {path}')
db = MaigretDatabase().load_from_file(path)

Type guard

import os

def file_exists(path: str) -> bool:
    return os.path.isfile(os.path.abspath(path))

Try / catch

try:
    db = MaigretDatabase().load_from_file(path)
except FileNotFoundError as err:
    logger.error('data file missing: %s', err)
    path = download_or_locate_db()  # fetch known-good copy
    db = MaigretDatabase().load_from_file(path)

Prevention

Reference data files with paths anchored to __file__ or absolute paths, never CWD-relative ones.
Include resources/data.json in Docker images and bundles; verify with a smoke test at startup.
Use MaigretDatabase.default_db() which resolves the packaged location for you.

When it happens

Trigger: Calling db.load_from_file('resources/data.json') when the file or the resources/ directory does not exist relative to the current working directory; passing an absolute path with a typo; deploying code where the data file was not packaged into the container/wheel.

Common situations: Running the tool from a different CWD than the checkout (relative path breaks), Docker images or PyInstaller bundles that omit resources/, cloned repo without fetched data files, or CI jobs on a fresh checkout where resources/data.json lives elsewhere.

Understand the failure class

Background: "File not found" and ENOENT errors: why libraries can't find a file that should exist — this error's family across 50 libraries.

Related errors

AI-assisted analysis of soxoj/maigret@41674631a9 (2026-08-27). Data as JSON: /api/errors/c8378c6ac58c42fe. Report an issue: GitHub.