No longer use CLIENT_HOME, INSTANCE_HOME, or ZEO_CLIENT environment

variables.  Updated docstrings/comments.

src/ZEO/ClientCache.py

@@ -122,16 +122,18 @@ from ZEO.ICache import ICache
 magic = 'ZEC1'
 headersize = 12
 
+MB = 1024**2
+
 class ClientCache:
 
     __implements__ = ICache
 
-    def __init__(self, storage='1', size=20000000, client=None, var=None):
+    def __init__(self, storage='1', size=20*MB, client=None, var=None):
         # Arguments:
         # storage -- storage name (used in filenames and log messages)
         # size -- size limit in bytes of both files together
         # client -- if not None, use a persistent cache file and use this name
-        # var -- directory where to create persistent cache files
+        # var -- directory where to create persistent cache files; default cwd
 
         self._storage = storage
         self._limit = size / 2
@@ -145,15 +147,8 @@ class ClientCache:
 
         if client is not None:
             # Create a persistent cache
-            # CLIENT_HOME and INSTANCE_HOME are builtins set by App.FindHomes
             if var is None:
-                try:
-                    var = CLIENT_HOME
-                except:
-                    try:
-                        var = os.path.join(INSTANCE_HOME, 'var')
-                    except:
-                        var = os.getcwd()
+                var = os.getcwd()
 
             fmt = os.path.join(var, "c%s-%s-%%s.zec" % (storage, client))
             # Initialize pairs of filenames, file objects, and serialnos.

src/ZEO/ClientStorage.py

@@ -141,16 +141,15 @@ class ClientStorage:
         name -- The storage name, defaulting to ''.  If this is false,
             str(addr) is used as the storage name.
 
-        client -- The client name, defaulting to None.  If this is
-            false, the environment value ZEO_CLIENT is used.  If the
-            effective value is true, the client cache is persistent.
-            See ClientCache for more info.
+        client -- A name used to construct persistent cache filenames.
+            Defaults to None, in which case the cache is not persistent.
 
         debug -- Ignored.  This is present only for backwards
             compatibility with ZEO 1.
 
-        var -- The 'var' directory, defaulting to None, in which
-            the persistent cache files should be written.
+        var -- When client is not None, this specifies the directory
+            where the persistent cache files are created.  It defaults
+            to None, in whichcase the current directory is used.
 
         min_disconnect_poll -- The minimum delay in seconds between
             attempts to connect to the server, in seconds.  Defaults
@@ -249,7 +248,7 @@ class ClientStorage:
         self._oid = '\0\0\0\0\0\0\0\0'
 
         # Decide whether to use non-temporary files
-        client = client or os.environ.get('ZEO_CLIENT')
+        client = client
         self._cache = self.ClientCacheClass(storage, cache_size,
                                             client=client, var=var)