[Libfix] Remove rpyc_get_connection() dependency from code

Problem:
`g.rpyc_get_connection()` has a limitaion where it can't
convert python2 calls to python3 calls. Due to this a large
number of testcases fail when executed from a python2 machine
on a python3 only setup or visa versa with the below stack trace:
```
E  ========= Remote Traceback (1) =========
E  Traceback (most recent call last):
E  File "/root/tmp.tL8Eqx7d8l/rpyc/core/protocol.py", line 323, in _dispatch_request
E       res = self._HANDLERS[handler](self, *args)
E  File "/root/tmp.tL8Eqx7d8l/rpyc/core/protocol.py", line 591, in _handle_inspect
E       if hasattr(self._local_objects[id_pack], '____conn__'):
E  File "/root/tmp.tL8Eqx7d8l/rpyc/lib/colls.py", line 110, in __getitem__
E       return self._dict[key][0]
E  KeyError: (b'rpyc.core.service.SlaveService', 94282642994712, 140067150858560)
```

Solution:
The solution here is to modify the code to not use
`g.rpyc_get_connection()`. The following changes are done
to accomplish it:
1)Remove code which uses g.rpyc_get_connection() and use generic
logic in functions:
 a. do_bricks_exist_in_shd_volfile()
 b. get_disk_usage()
 c. mount_volume()
 d. list_files()
 f. append_string_to_file()
2)Create files which can be uploaded and executed on
clients/servers to avoid rpc calls in functions:
 a. calculate_hash()
 b. validate_files_in_dir()
3)Modify setup.py to push the below files to
`/usr/share/glustolibs/scripts/`:
 a.compute_hash.py
 b.walk_dir.py

Change-Id: I00a81a88382bf3f8b366753eebdb2999260788ca
Signed-off-by: kshithijiyer <kshithij.ki@gmail.com>

1 files changed, 20 insertions, 7 deletions

diff --git a/glustolibs-gluster/glustolibs/gluster/dht_test_utils.py b/glustolibs-gluster/glustolibs/gluster/dht_test_utils.py
index 8cef3015b..55dcce5c7 100644
--- a/glustolibs-gluster/glustolibs/gluster/dht_test_utils.py
+++ b/glustolibs-gluster/glustolibs/gluster/dht_test_utils.py
@@ -22,7 +22,7 @@ import os
 from glusto.core import Glusto as g
 
 from glustolibs.gluster.glusterfile import (GlusterFile, calculate_hash,
-                                            get_pathinfo)
+                                            get_pathinfo, file_exists)
 from glustolibs.gluster.glusterdir import GlusterDir
 from glustolibs.gluster.layout import Layout
 import glustolibs.gluster.constants as k
@@ -30,6 +30,7 @@ import glustolibs.gluster.exceptions as gex
 from glustolibs.gluster.brickdir import BrickDir
 from glustolibs.gluster.volume_libs import get_subvols, get_volume_type
 from glustolibs.gluster.gluster_init import get_gluster_version
+from glustolibs.misc.misc_libs import upload_scripts
 
 
 def run_layout_tests(mnode, fqpath, layout, test_type):
@@ -120,11 +121,25 @@ def validate_files_in_dir(mnode, rootdir,
     """
     layout_cache = {}
 
-    conn = g.rpyc_get_connection(mnode)
-    if conn is None:
-        g.log.info("Not able to establish connection to node %s" % mnode)
+    script_path = ("/usr/share/glustolibs/scripts/walk_dir.py")
+    if not file_exists(mnode, script_path):
+        if upload_scripts(mnode, script_path,
+                          "/usr/share/glustolibs/scripts/"):
+            g.log.info("Successfully uploaded script "
+                       "walk_dir.py!")
+        else:
+            g.log.error("Faild to upload walk_dir.py!")
+            return False
+    else:
+        g.log.info("compute_hash.py already present!")
+
+    cmd = ("/usr/bin/env python {0} {1}".format(script_path, rootdir))
+    ret, out, _ = g.run(mnode, cmd)
+    if ret:
+        g.log.error('Unable to run the script on node {0}'
+                    .format(mnode))
         return False
-    for walkies in conn.modules.os.walk(rootdir):
+    for walkies in eval(out):
         g.log.info("TESTING DIRECTORY %s..." % walkies[0])
 
         # check directories
@@ -161,8 +176,6 @@ def validate_files_in_dir(mnode, rootdir,
 
                 if test_type & k.TEST_FILE_EXISTS_ON_HASHED_BRICKS:
                     run_hashed_bricks_test(gfile)
-
-    g.rpyc_close_connection(mnode)
     return True