added a shell command with result, leveraged it usage to get output for failures during addfile and mounting within nodes

daemon/core/netns/vnode.py

@@ -172,8 +172,10 @@ class SimpleLxcNode(PyCoreNode):
         source = os.path.abspath(source)
         logger.info("mounting %s at %s" % (source, target))
         try:
-            shcmd = 'mkdir -p "%s" && %s -n --bind "%s" "%s"' % (target, constants.MOUNT_BIN, source, target)
-            self.client.shcmd(shcmd)
+            cmd = 'mkdir -p "%s" && %s -n --bind "%s" "%s"' % (target, constants.MOUNT_BIN, source, target)
+            status, output = self.client.shcmd_result(cmd)
+            if status:
+                raise IOError("error during mount: %s" % output)
             self._mounts.append((source, target))
         except IOError:
             logger.exception("mounting failed for %s at %s", source, target)
@@ -446,8 +448,16 @@ class SimpleLxcNode(PyCoreNode):
         :param str filename: file name to add
         :return: nothing
         """
-        shcmd = 'mkdir -p $(dirname "%s") && mv "%s" "%s" && sync' % (filename, srcname, filename)
-        self.client.shcmd(shcmd)
+        logger.info("adding file from %s to %s", srcname, filename)
+        directory = os.path.dirname(filename)
+
+        try:
+            cmd = 'mkdir -p "%s" && mv "%s" "%s" && sync' % (directory, srcname, filename)
+            status, output = self.client.shcmd_result(cmd)
+            if status:
+                logger.error("error adding file: %s", output)
+        except IOError:
+            logger.exception("error during addfile")
 
     def getaddr(self, ifname, rescan=False):
         """

daemon/core/netns/vnodeclient.py

@@ -6,6 +6,7 @@ by invoking the vcmd shell command.
 """
 
 import os
+import shlex
 
 import vcmd
 
@@ -93,6 +94,10 @@ class VnodeClient(object):
         """
         self._verify_connection()
 
+        # split shell string to shell array for convenience
+        if type(args) == str:
+            args = shlex.split(args)
+
         p, stdin, stdout, stderr = self.popen(args)
         output = stdout.read() + stderr.read()
         stdin.close()
@@ -184,6 +189,17 @@ class VnodeClient(object):
         """
         return self.cmd([sh, "-c", cmdstr])
 
+    def shcmd_result(self, cmd, sh="/bin/sh"):
+        """
+        Execute a shell command and return the exist status and combined output.
+
+        :param str cmd: shell command to run
+        :param str sh: shell to run command in
+        :return: exist status and combined output
+        :rtype: tuple[int, str]
+        """
+        return self.cmdresult([sh, "-c", cmd])
+
     def getaddr(self, ifname, rescan=False):
         """
         Get address for interface on node.

daemon/tests/test_core.py

@@ -186,7 +186,6 @@ class TestCore:
         assert not client.shcmd(command[0])
 
         # check various command using command line
-        vnodeclient.USE_VCMD_MODULE = False
         assert not client.cmd(command)
         status, output = client.cmdresult(command)
         assert not status