Force pi0_libero to be re-downloaded (#275)

src/openpi/shared/download.py

@@ -37,7 +37,7 @@ def get_cache_dir() -> pathlib.Path:
     return cache_dir
 
 
-def maybe_download(url: str, **kwargs) -> pathlib.Path:
+def maybe_download(url: str, *, force_download: bool = False, **kwargs) -> pathlib.Path:
     """Download a file or directory from a remote filesystem to the local cache, and return the local path.
 
     If the local file already exists, it will be returned directly.
@@ -47,6 +47,7 @@ def maybe_download(url: str, **kwargs) -> pathlib.Path:
 
     Args:
         url: URL to the file to download.
+        force_download: If True, the file will be downloaded even if it already exists in the cache.
         **kwargs: Additional arguments to pass to fsspec.
 
     Returns:
@@ -67,33 +68,56 @@ def maybe_download(url: str, **kwargs) -> pathlib.Path:
     local_path = cache_dir / parsed.netloc / parsed.path.strip("/")
     local_path = local_path.resolve()
 
-    # Check if file already exists in cache.
-    if local_path.exists() and not _invalidate_expired_cache(cache_dir, local_path):
-        return local_path
-
-    # Download file from remote file system.
-    logger.info(f"Downloading {url} to {local_path}")
-    with filelock.FileLock(local_path.with_suffix(".lock")):
-        scratch_path = local_path.with_suffix(".partial")
-
-        if _is_openpi_url(url):
-            # Download without credentials.
-            _download_boto3(
-                url,
-                scratch_path,
-                boto_session=boto3.Session(
-                    region_name="us-west-1",
-                ),
-                botocore_config=botocore.config.Config(signature_version=botocore.UNSIGNED),
-            )
-        elif url.startswith("s3://"):
-            # Download with default boto3 credentials.
-            _download_boto3(url, scratch_path)
+    # Check if the cache should be invalidated.
+    invalidate_cache = False
+    if local_path.exists():
+        if force_download or _should_invalidate_cache(cache_dir, local_path):
+            invalidate_cache = True
         else:
-            _download_fsspec(url, scratch_path, **kwargs)
+            return local_path
 
-        shutil.move(scratch_path, local_path)
-        _ensure_permissions(local_path)
+    try:
+        lock_path = local_path.with_suffix(".lock")
+        with filelock.FileLock(lock_path):
+            # Ensure consistent permissions for the lock file.
+            _ensure_permissions(lock_path)
+            # First, remove the existing cache if it is expired.
+            if invalidate_cache:
+                logger.info(f"Removing expired cached entry: {local_path}")
+                if local_path.is_dir():
+                    shutil.rmtree(local_path)
+                else:
+                    local_path.unlink()
+
+            # Download the data to a local cache.
+            logger.info(f"Downloading {url} to {local_path}")
+            scratch_path = local_path.with_suffix(".partial")
+
+            if _is_openpi_url(url):
+                # Download without credentials.
+                _download_boto3(
+                    url,
+                    scratch_path,
+                    boto_session=boto3.Session(
+                        region_name="us-west-1",
+                    ),
+                    botocore_config=botocore.config.Config(signature_version=botocore.UNSIGNED),
+                )
+            elif url.startswith("s3://"):
+                # Download with default boto3 credentials.
+                _download_boto3(url, scratch_path)
+            else:
+                _download_fsspec(url, scratch_path, **kwargs)
+
+            shutil.move(scratch_path, local_path)
+            _ensure_permissions(local_path)
+
+    except PermissionError as e:
+        msg = (
+            f"Local file permission error was encountered while downloading {url}. "
+            f"Please try again after removing the cached data using: `rm -rf {local_path}*`"
+        )
+        raise PermissionError(msg) from e
 
     return local_path
 
@@ -285,11 +309,12 @@ def _get_mtime(year: int, month: int, day: int) -> float:
 # Partial matching will be used from top to bottom and the first match will be chosen.
 # Cached entries will be retained only if they are newer than the expiration timestamp.
 _INVALIDATE_CACHE_DIRS: dict[re.Pattern, float] = {
+    re.compile("openpi-assets/checkpoints/pi0_libero"): _get_mtime(2025, 2, 6),
     re.compile("openpi-assets/checkpoints/"): _get_mtime(2025, 2, 3),
 }
 
 
-def _invalidate_expired_cache(cache_dir: pathlib.Path, local_path: pathlib.Path) -> bool:
+def _should_invalidate_cache(cache_dir: pathlib.Path, local_path: pathlib.Path) -> bool:
     """Invalidate the cache if it is expired. Return True if the cache was invalidated."""
 
     assert local_path.exists(), f"File not found at {local_path}"
@@ -298,13 +323,6 @@ def _invalidate_expired_cache(cache_dir: pathlib.Path, local_path: pathlib.Path)
     for pattern, expire_time in _INVALIDATE_CACHE_DIRS.items():
         if pattern.match(relative_path):
             # Remove if not newer than the expiration timestamp.
-            if local_path.stat().st_mtime <= expire_time:
-                logger.info(f"Removing expired cached entry: {local_path}")
-                if local_path.is_dir():
-                    shutil.rmtree(local_path)
-                else:
-                    local_path.unlink()
-                return True
-            return False
+            return local_path.stat().st_mtime <= expire_time
 
     return False