media info - better imports

pytorrent/services/rtorrent/files.py

@@ -225,6 +225,34 @@ def _media_info_summary(fields: list[dict]) -> dict:
     }
 
 
+def _media_info_hachoir_imports():
+    # Note: Import is checked before reading the media sample so dependency problems fail fast and clearly.
+    import sys
+
+    try:
+        from hachoir.metadata import extractMetadata
+        from hachoir.parser import createParser
+        return createParser, extractMetadata
+    except ModuleNotFoundError as exc:
+        missing = str(getattr(exc, "name", "") or "hachoir")
+        if missing.split(".", 1)[0] == "hachoir":
+            raise RuntimeError(
+                "Python package 'hachoir' is not importable in the application runtime. "
+                "Install it inside the pyTorrent virtualenv and restart the service: "
+                "/opt/pyTorrent/venv/bin/pip install -r /opt/pyTorrent/requirements.txt && systemctl restart pytorrent. "
+                f"Runtime: {sys.executable}."
+            ) from exc
+        raise RuntimeError(
+            f"hachoir is installed, but one of its Python dependencies is missing: {missing}. "
+            f"Runtime: {sys.executable}."
+        ) from exc
+    except Exception as exc:
+        raise RuntimeError(
+            "hachoir was found, but failed during import. "
+            f"Runtime: {sys.executable}. Details: {exc}"
+        ) from exc
+
+
 def torrent_file_media_info(profile: dict, torrent_hash: str, index: int, max_bytes: int = _MEDIA_INFO_SAMPLE_BYTES) -> dict:
     # Note: This endpoint is MediaInfo-like and intentionally avoids external binaries such as mediainfo, ffprobe or ffmpeg.
     selected, remote_path = _torrent_file_remote_path(profile, torrent_hash, index)
@@ -246,6 +274,8 @@ def torrent_file_media_info(profile: dict, torrent_hash: str, index: int, max_by
         result["error"] = "This file extension is not supported by the built-in media info parser."
         return result
 
+    createParser, extractMetadata = _media_info_hachoir_imports()
+
     err = remote_file_readability_error(profile, remote_path) if int(profile.get("is_remote") or 0) else None
     if err:
         raise RuntimeError(err)
@@ -253,12 +283,6 @@ def torrent_file_media_info(profile: dict, torrent_hash: str, index: int, max_by
     tmp_path = None
     try:
         tmp_path, written = _media_info_temp_sample(profile, remote_path, max(1024 * 1024, int(max_bytes)))
-        try:
-            from hachoir.metadata import extractMetadata
-            from hachoir.parser import createParser
-        except Exception as exc:
-            raise RuntimeError("Python package 'hachoir' is required for media info. Install requirements.txt again.") from exc
-
         parser = createParser(tmp_path, real_filename=LocalPath(name).name)
         if parser is None:
             result.update({"sample_bytes": written, "error": "hachoir could not detect this media container."})