Make joblib an optional dependency

Author: apdavison

neo/rawio/baserawio.py

@@ -156,7 +156,6 @@ def __init__(self, use_cache=False, cache_path='same_as_resource', **kargs):
 
         self.use_cache = use_cache
         if use_cache:
-            import joblib
             self.setup_cache(cache_path)
         else:
             self._cache = None
@@ -697,7 +696,10 @@ def rescale_epoch_duration(self, raw_duration, dtype='float64',
         return self._rescale_epoch_duration(raw_duration, dtype, event_channel_index)
 
     def setup_cache(self, cache_path, **init_kargs):
-        import joblib
+        try:
+            import joblib
+        except ImportError:
+            raise ImportError("Using the RawIO cache needs joblib to be installed")
 
         if self.rawmode in ('one-file', 'multi-file'):
             resource_name = self.filename

pyproject.toml

@@ -24,8 +24,7 @@ classifiers = [
 dependencies = [
     "packaging",
     "numpy>=1.19.5",
-    "quantities>=0.14.1",
-    "joblib>=1.0.0"
+    "quantities>=0.14.1"
 ]
 
 [project.urls]
@@ -41,6 +40,10 @@ build-backend = "setuptools.build_meta"
 
 [project.optional-dependencies]
 
+iocache = [
+    "joblib>=1.0.0"
+]
+
 test = [
     "pytest",
     "pytest-cov",
@@ -60,6 +63,7 @@ test = [
     "sonpy",
     "pynwb",
     "probeinterface",
+    "joblib>=1.0.0"
 ]
 
 docs = [
@@ -96,5 +100,6 @@ all = [
     "scipy>=1.0.0",
     "sonpy",
     "tqdm",
+    "joblib>=1.0.0"
 ]
 # we do not include 'stfio' in 'all' as it is not pip installable