Have the diskcache long_callback manager rely on multiprocess on all …

…platforms
plotly · jonmmease · Aug 18, 2021 · Aug 7, 2021 · Aug 11, 2021 · Aug 11, 2021
commit 0b106242a7944fdab4f7714448043657378a3530
@@ -1,38 +1,30 @@
-import platform
 from . import BaseLongCallbackManager
 
 
 class DiskcacheLongCallbackManager(BaseLongCallbackManager):
     def __init__(self, cache, cache_by=None, expire=None):
-        import diskcache  # pylint: disable=import-outside-toplevel
-
-        if not isinstance(cache, diskcache.Cache):
-            raise ValueError("First argument must be a diskcache.Cache object")
-        super().__init__(cache_by)
-
-        # Handle process class import
-        if platform.system() == "Windows":
-            try:
-                from multiprocess import (  # pylint: disable=import-outside-toplevel
-                    Process,
-                )
-            except ImportError:
-                raise ImportError(
-                    """\
-    When running on Windows, the long_callback decorator requires the
-    multiprocess package which can be install using pip...
+        try:
+            import diskcache  # pylint: disable=import-outside-toplevel
+            from multiprocess import (  # pylint: disable=import-outside-toplevel
+                Process,
+            )
+        except ImportError:
+            raise ImportError(
+                """\
+DiskcacheLongCallbackManager requires the multiprocess and diskcache packages which
+can be installed using pip...
 
-        $ pip install multiprocess
+    $ pip install multiprocess diskcache
 
-    or conda.
+or conda.
 
-        $ conda install -c conda-forge multiprocess\n"""
-                )
-        else:
-            from multiprocessing import (  # pylint: disable=import-outside-toplevel
-                Process,
+    $ conda install -c conda-forge multiprocess diskcache\n"""
             )
 
+        if not isinstance(cache, diskcache.Cache):
+            raise ValueError("First argument must be a diskcache.Cache object")
+        super().__init__(cache_by)
+
         self.Process = Process
         self.cache = cache
         self.callback_futures = dict()

@@ -8,4 +8,5 @@ cryptography<3.4;python_version<"3.7"
 requests[security]>=2.21.0
 beautifulsoup4>=4.8.2
 waitress>=1.4.4
-diskcache=>5.2.1
+diskcache>=5.2.1
+multiprocess>=0.70.12