Don't import pyarrow just to check version

fsspec/spec.py

@@ -2,14 +2,20 @@
 import logging
 import os
 import warnings
-from distutils.version import LooseVersion
 from errno import ESPIPE
 from hashlib import sha256
+from distutils.version import LooseVersion
 from glob import has_magic
 
 from .dircache import DirCache
 from .transaction import Transaction
-from .utils import read_block, tokenize, stringify_path, other_paths
+from .utils import (
+    read_block,
+    tokenize,
+    stringify_path,
+    other_paths,
+    get_package_version_without_import,
+)
 from .config import apply_config
 
 logger = logging.getLogger("fsspec")
@@ -72,16 +78,13 @@ def __call__(cls, *args, **kwargs):
             return obj
 
 
-try:  # optionally derive from pyarrow's FileSystem, if available
+pa_version = get_package_version_without_import("pyarrow")
+if pa_version and LooseVersion(pa_version) < LooseVersion("2.0"):
     import pyarrow as pa
-except ImportError:
-    up = object
+
+    up = pa.filesystem.DaskFileSystem
 else:
-    # only derive from the legacy pyarrow's FileSystem for older pyarrow versions
-    if LooseVersion(pa.__version__) < LooseVersion("2.0"):
-        up = pa.filesystem.DaskFileSystem
-    else:
-        up = object
+    up = object
 
 
 class AbstractFileSystem(up, metaclass=_Cached):

fsspec/utils.py

@@ -3,6 +3,7 @@
 import os
 import pathlib
 import re
+import sys
 from urllib.parse import urlsplit
 
 
@@ -383,10 +384,13 @@ def can_be_local(path):
         return False
 
 
-def setup_logger(logname, level="DEBUG"):
+def setup_logger(logname, level="DEBUG", clear=True):
+    """Add standard logging handler to logger of given name"""
     import logging
 
     logger = logging.getLogger(logname)
+    if clear:
+        logger.handlers.clear()
     handle = logging.StreamHandler()
     formatter = logging.Formatter(
         "%(asctime)s - %(name)s - %(levelname)s " "- %(message)s"
@@ -395,3 +399,39 @@ def setup_logger(logname, level="DEBUG"):
     logger.addHandler(handle)
     logger.setLevel(level)
     return logger
+
+
+def get_package_version_without_import(name):
+    """For given package name, try to find the version without importing it
+
+    Import and package.__version__ is still the backup here, so an import
+    *might* happen.
+
+    Returns either the version string, or None if the package
+    or the version was not readily  found.
+    """
+    if name in sys.modules:
+        mod = sys.modules[name]
+        if hasattr(mod, "__version__"):
+            return mod.__version__
+    if sys.version_info >= (3, 8):
+        try:
+            import importlib.metadata
+
+            return importlib.metadata.distribution(name).version
+        except ImportError:
+            pass
+    else:
+        try:
+            import importlib_metadata
+
+            return importlib_metadata.distribution(name).version
+        except ImportError:
+            pass
+    try:
+        import importlib
+
+        mod = importlib.import_module(name)
+        return mod.__version__
+    except (ImportError, AttributeError):
+        return None