deepset-ai/haystack · error · FileNotFoundError

File not found: {file_path}

Error message

File not found: {file_path}

What it means

load_pipeline_snapshot() opens the given path to read a JSON snapshot and re-raises FileNotFoundError with the resolved path when the file does not exist. It exists so callers resuming from a saved breakpoint get a clear message naming the missing file.

Source

Thrown at haystack/core/pipeline/breakpoint.py:116

    )


def load_pipeline_snapshot(file_path: str | Path) -> PipelineSnapshot:
    """
    Load a saved pipeline snapshot.

    :param file_path: Path to the pipeline_snapshot file.
    :returns:
        Dict containing the loaded pipeline_snapshot.
    """

    file_path = Path(file_path)

    try:
        with open(file_path, encoding="utf-8") as f:
            pipeline_snapshot_dict = json.load(f)
    except FileNotFoundError as e:
        raise FileNotFoundError(f"File not found: {file_path}") from e
    except json.JSONDecodeError as e:
        raise json.JSONDecodeError(f"Invalid JSON file {file_path}: {str(e)}", e.doc, e.pos) from e
    except OSError as e:
        raise OSError(f"Error reading {file_path}: {str(e)}") from e

    try:
        pipeline_snapshot = PipelineSnapshot.from_dict(pipeline_snapshot_dict)
    except ValueError as e:
        raise ValueError(f"Invalid pipeline snapshot from {file_path}: {str(e)}") from e

    logger.info("Successfully loaded the pipeline snapshot from: {file_path}", file_path=file_path)
    return pipeline_snapshot


def _save_pipeline_snapshot(
    pipeline_snapshot: PipelineSnapshot,
    raise_on_failure: bool = True,
    snapshot_callback: SnapshotCallback | None = None,

View on GitHub (pinned to e318778c9b)

Solutions

1. Verify the file exists and fix the path: os.path.exists() / Path(file_path).resolve() before loading.
2. Use absolute paths when saving and resuming snapshots to avoid cwd differences.
3. Catch FileNotFoundError around load_pipeline_snapshot and prompt the user to re-save the snapshot.

Example fix

// before
snapshot = load_pipeline_snapshot("snapshot.json")
// after
from pathlib import Path
p = Path("snapshots").resolve() / "snapshot.json"
if not p.exists():
    raise SystemExit(f"Snapshot missing: {p}")
snapshot = load_pipeline_snapshot(str(p))

from pathlib import Path
p = Path(file_path)
if not p.is_file():
    raise FileNotFoundError(f"Snapshot missing: {p.resolve()}")

def snapshot_file_exists(path) -> bool:
    from pathlib import Path
    return Path(path).is_file()

try:
    snapshot = load_pipeline_snapshot(file_path)
except FileNotFoundError as e:
    logger.error("Snapshot file missing: %s", e)

When it happens

Trigger: Calling load_pipeline_snapshot("path/to/snapshot.json") with a non-existent path; wrong working directory when a relative path is used; file deleted between save and resume.

Common situations: Typo in the snapshot file name; running the resume from a different cwd so a relative path no longer resolves; cleanup scripts removing tmp snapshot files before resume.

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

• Error reading {file_path}: {str(e)}
• Invalid pipeline snapshot: components {invalid_ordered_compo
• Invalid pipeline snapshot: components {invalid_input_data} i
• Invalid pipeline snapshot: components {invalid_component_vis
• The following tool names are not valid: {invalid_tool_names}

AI-assisted analysis of deepset-ai/haystack@e318778c9b (2026-08-30). Data as JSON: /api/errors/c1f9b67d1909ec5d. Report an issue: GitHub.