sgl-project/sglang · error · FileNotFoundError

Prompt text file not found: {path}

Error message

Prompt text file not found: {path}

What it means

DiffusionGenerator._resolve_prompts raises FileNotFoundError when the prompt file given via prompt_path (or the server-level --prompt-file-path) does not exist on disk. Prompts are read line-by-line from this file before any request is built.

Source

Thrown at python/sglang/multimodal_gen/runtime/entrypoints/diffusion_generator.py:485

            external_trace_header=external_trace_header,
        )
        output_batch = self._send_to_scheduler_and_wait_for_response(req)
        if output_batch.error:
            raise RuntimeError(output_batch.error)
        if output_batch.output is None:
            raise RuntimeError("action policy returned no output")
        return output_batch.output[0]

    def _resolve_prompts(
        self,
        prompt: str | list[str] | None,
        prompt_path: str | None = None,
    ) -> list[str]:
        """Collect prompts from the argument or from a prompt file."""
        path = prompt_path or self.server_args.prompt_file_path
        if path is not None:
            if not os.path.exists(path):
                raise FileNotFoundError(f"Prompt text file not found: {path}")
            with open(path, encoding="utf-8") as f:
                prompts = [line.strip() for line in f if line.strip()]
            if not prompts:
                raise ValueError(f"No prompts found in file: {path}")
            logger.info("Found %d prompts in %s", len(prompts), path)
            return prompts

        if prompt is None:
            return [" "]
        if isinstance(prompt, str):
            return [prompt]
        return list(prompt)

    def _log_summary(self, results: list[GenerationResult]) -> None:
        if not results:
            return
        if self.server_args.warmup_mode != "off":
            total_duration_ms = results[0].metrics.get("total_duration_ms", 0)

View on GitHub (pinned to 0132848349)

Solutions

1. Check the path exists: os.path.exists(path) before calling generate
2. Use an absolute path for prompt_path / --prompt-file-path
3. If running in Docker, verify the file is mounted into the container
4. Fix typos or regenerate the prompt file

Example fix

# before
generator.generate(prompt_path="prompts.txt")
# after
from pathlib import Path
p = Path("prompts.txt").resolve()
assert p.exists(), f"missing prompt file: {p}"
generator.generate(prompt_path=str(p))

import os
if prompt_path and not os.path.exists(prompt_path):
    raise SystemExit(f"prompt file missing: {prompt_path}")

When it happens

Trigger: Calling generate(prompt_path='prompts.txt') where prompts.txt is missing; launching with --prompt-file-path pointing to a wrong/relative path; running from a different working directory so a relative path no longer resolves.

Common situations: Relative paths resolved against the wrong CWD (client vs server process); typo in the filename; file not mounted into a container; path from config pointing to a removed file.

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

• No prompts found in file: {path}
• Image path not found: {batch.image_path}
• metal shader source not found: {metal_src}
• unsupported input for causal Conv3D cat/pad CUDA
• unsupported input for usp_merge_heads CUDA

AI-assisted analysis of sgl-project/sglang@0132848349 (2026-08-28). Data as JSON: /api/errors/570a00f14adfb2b5. Report an issue: GitHub.