proof-of-concept of dynamically loading a backstore instanceuser-backstore-poc

2 files changed, 91 insertions, 1 deletions

diff --git a/targetcli/dynbs_gluster.py b/targetcli/dynbs_gluster.py
new file mode 100644
index 0000000..44ad3b5
--- /dev/null
+++ b/targetcli/dynbs_gluster.py
@@ -0,0 +1,62 @@
+'''
+Implements the targetcli backstores related UI.
+
+Copyright (c) 2015 by Red Hat, Inc
+
+Licensed under the Apache License, Version 2.0 (the "License"); you may
+not use this file except in compliance with the License. You may obtain
+a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+License for the specific language governing permissions and limitations
+under the License.
+'''
+
+from rtslib_fb import UserBackedStorageObject
+
+# Note: Since this is exec'd at the end of ui_backstore.py, both
+# UIUserBackstore and UIUserBackedStorageObject are already in scope.
+
+class UIGlusterBackstore(UIUserBackstore):
+
+    def __init__(self, parent):
+        self.so_cls = UIUserBackedStorageObject
+        super(self.__class__, self).__init__("gluster", parent)
+
+    def ui_command_create(self, name, size, server, volume, path):
+        '''
+        Creates a Gluster-backed storage object.
+
+        SIZE SYNTAX
+        ===========
+        - If size is an int, it represents a number of bytes.
+        - If size is a string, the following units can be used:
+            - B{B} or no unit present for bytes
+            - B{k}, B{K}, B{kB}, B{KB} for kB (kilobytes)
+            - B{m}, B{M}, B{mB}, B{MB} for MB (megabytes)
+            - B{g}, B{G}, B{gB}, B{GB} for GB (gigabytes)
+            - B{t}, B{T}, B{tB}, B{TB} for TB (terabytes)
+
+        'server' is the name of the Gluster server.
+        'volume' is the name of the Gluster volume.
+        'path' is the name of the path in the volume.
+
+        I{server}, I{volume}, and I{path} are also all required.
+        '''
+        self.assert_root()
+
+        size = human_to_bytes(size)
+        config = "gluster/%s@%s/%s" % (server, volume, path)
+        so = UserBackedStorageObject(name, size=size, config=config, level=1)
+        ui_so = UIUserBackedStorageObject(so, self)
+        self.setup_model_alias(so)
+        self.shell.log.info("Created Gluster storage object %s"
+                            % (name,))
+        return self.new_node(ui_so)
+
+
+new_backstore(UIGlusterBackstore)
diff --git a/targetcli/ui_backstore.py b/targetcli/ui_backstore.py
index 90708d9..a8b8b12 100644
--- a/targetcli/ui_backstore.py
+++ b/targetcli/ui_backstore.py
@@ -29,6 +29,8 @@ import os
 import stat
 import re
 
+dynload_backstore_path = "/home/agrover/git/targetcli-fb/targetcli/dynbs_*"
+
 def human_to_bytes(hsize, kilo=1024):
     '''
     This function converts human-readable amounts of bytes to bytes.
@@ -93,6 +95,7 @@ def complete_path(path, stat_fn):
     return sorted(filtered,
                   key=lambda s: '~'+s if s.endswith('/') else s)
 
+
 class UIBackstores(UINode):
     '''
     The backstores container UI.
@@ -107,7 +110,9 @@ class UIBackstores(UINode):
         UIRDMCPBackstore(self)
         UIFileIOBackstore(self)
         UIBlockBackstore(self)
-        UIUserBackedBackstore(self)
+
+        for entry in dyn_bs_list:
+            entry(self)
 
 
 class UIBackstore(UINode):
@@ -182,6 +187,21 @@ class UIBackstore(UINode):
                                      " emulate_model_alias\n  not supported by kernel.")
 
 
+class UIUserBackstore(UIBackstore):
+    '''
+    Common code for user-backed backstores
+    Abstract Base Class, do not instantiate.
+    '''
+    def summary(self):
+            return ("User-backed Storage Objects: %d" % len(self._children), None)
+
+    def refresh(self):
+        self._children = set([])
+        for so in RTSRoot().storage_objects:
+            if so.plugin == 'user' and so.config.startswith(self.name + '/'):
+                ui_so = self.so_cls(so, self)
+
+
 class UIPSCSIBackstore(UIBackstore):
     '''
     PSCSI backstore UI.
@@ -552,3 +572,11 @@ class UIUserBackedStorageObject(UIStorageObject):
             config_str = so.config
 
         return ("%s (%s) %s" % (config_str, bytes_to_human(so.size), so.status), True)
+
+
+dyn_bs_list = []
+def new_backstore(bs_cls):
+    dyn_bs_list.append(bs_cls)
+
+for file in glob.iglob(dynload_backstore_path):
+    execfile(file)