[Kimchi-devel] [PATCH] [WoK 1/2] wok/utils.py: adding utility 'get model instances' methods

[dhbarboza82 at gmail.com]

From: Daniel Henrique Barboza <danielhb at linux.vnet.ibm.com>

To avoid the shameless code repetition we have today widespread
across all plug-ins and WoK itself, this patch consolidates
the process of retrieving all the model instances from the
current dir of a given base (root) model file.

'get_model_instances' is a helper function to retrieve any
Model instances from a given module.

'get_all_model_instances' is a function that consolidates
the logic all plug-ins up to this date were using to load
all the 'Model' instances from the model dir. Refer to the
function doc string for more info.

Signed-off-by: Daniel Henrique Barboza <danielhb at linux.vnet.ibm.com>
---
 src/wok/utils.py | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/src/wok/utils.py b/src/wok/utils.py
index d6bdf0a..f5f864a 100644
--- a/src/wok/utils.py
+++ b/src/wok/utils.py
@@ -23,6 +23,7 @@
 import cherrypy
 import glob
 import grp
+import inspect
 import os
 import psutil
 import pwd
@@ -311,6 +312,65 @@ def listPathModules(path):
     return sorted(modules)
 
 
+def get_model_instances(module_name):
+    instances = []
+    module = import_module(module_name)
+    members = inspect.getmembers(module, inspect.isclass)
+    for cls_name, instance in members:
+        if inspect.getmodule(instance) == module and \
+           cls_name.endswith('Model'):
+            instances.append(instance)
+    return instances
+
+
+def get_all_model_instances(root_model_name, root_model_file,
+                            kwargs):
+    """Function that returns all model instances from all modules
+    found on the same dir as root_model_name module.
+
+    The intended use of this function is to be called from a root
+    model class that subclasses BaseModel to get all model instances
+    contained in its dir. This module array would then be used in
+    the super init call of BaseModel.
+
+    The root model itself is ignored in the return array.
+
+    Args:
+        root_model_name (str): the python name of the root module. For
+            example, in WoK case it would be 'wok.model.model'. This
+            value can be retrieved by calling '__name__' inside the root
+            model file.
+
+        root_model_file (str): the absolute file name of the root model.
+            This can be retrived by calling '__file__' in the root model
+            file.
+
+        kwargs (dict): keyword arguments to be used to initiate the
+            models found. For example, {'objstore': ...}
+
+    Returns:
+        array: an array with all module instances found, excluding the
+            root module itself.
+
+    """
+    models = []
+
+    root_model = os.path.basename(root_model_file)
+    ignore_mod = os.path.splitext(root_model)[0]
+
+    package_namespace = root_model_name.rsplit('.', 1)[0]
+
+    for mod_name in listPathModules(os.path.dirname(root_model_file)):
+        if mod_name.startswith("_") or mod_name == ignore_mod:
+            continue
+
+        instances = get_model_instances(package_namespace + '.' + mod_name)
+        for instance in instances:
+            models.append(instance(**kwargs))
+
+    return models
+
+
 def run_setfacl_set_attr(path, attr="r", user=""):
     set_user = ["setfacl", "--modify", "user:%s:%s" % (user, attr), path]
     out, error, ret = run_command(set_user)
-- 
2.5.5