tests: Add error.context() for vlan.py script.

This patch add error.context for vlan.py script.
All update the steps in doc string.
Move sub function onto top of function code.

We may still need a patch to sync script with test case.
Signed-off-by: NFeng Yang <fyang@redhat.com>
Acked-by: NSuqin Huang <shuang@redhat.com>

tests/vlan.py

@@ -3,55 +3,58 @@ from autotest.client.shared import error
 from virttest import utils_misc, utils_test, aexpect, utils_net
 
 
+@error.context_aware
 def run_vlan(test, params, env):
     """
     Test 802.1Q vlan of NIC, config it by vconfig command.
 
     1) Create two VMs.
-    2) Setup guests in 10 different vlans by vconfig and using hard-coded
+    2) load 8021q module in guest for vconfig.
+    3) Setup vlans by vconfig in guest and using hard-coded
        ip address.
-    3) Test by ping between same and different vlans of two VMs.
-    4) Test by TCP data transfer, floop ping between same vlan of two VMs.
-    5) Test maximal plumb/unplumb vlans.
-    6) Recover the vlan config.
+    4) Enable arp_ignore for all ipv4 device in guest.
+    5) Repeat steps 2 - 4 in every guest.
+    6) Test by ping between same and different vlans of two VMs.
+    7) Test by flood ping between same vlan of two VMs.
+    8) Test by TCP data transfer between same vlan of two VMs.
+    9) Remove the named vlan-device.
+    10) Test maximal plumb/unplumb vlans.
 
     @param test: QEMU test object.
     @param params: Dictionary with the test parameters.
     @param env: Dictionary with test environment.
     """
-    vm = []
-    session = []
-    ifname = []
-    vm_ip = []
-    digest_origin = []
-    vlan_ip = ['', '']
-    ip_unit = ['1', '2']
-    subnet = params.get("subnet")
-    vlan_num = int(params.get("vlan_num"))
-    maximal = int(params.get("maximal"))
-    file_size = params.get("file_size")
 
-    vm.append(env.get_vm(params["main_vm"]))
-    vm.append(env.get_vm("vm2"))
-    for vm_ in vm:
-        vm_.verify_alive()
 
     def add_vlan(session, v_id, iface="eth0"):
+        txt = "Create a vlan-device on interface %s with vlan id %s" % (iface,
+                                                                        v_id)
+        error.context(txt, logging.info)
         session.cmd("vconfig add %s %s" % (iface, v_id))
 
+
     def set_ip_vlan(session, v_id, ip, iface="eth0"):
         iface = "%s.%s" % (iface, v_id)
+        txt = "Set ip to '%s' for interface '%s'" % (iface, ip)
+        error.context(txt, logging.info)
         session.cmd("ifconfig %s %s" % (iface, ip))
 
+
     def set_arp_ignore(session, iface="eth0"):
+        error.context("Enable arp_ignore for all ipv4 device  in guest",
+                       logging.info)
         ignore_cmd = "echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore"
         session.cmd(ignore_cmd)
 
+
     def rem_vlan(session, v_id, iface="eth0"):
         rem_vlan_cmd = "if [[ -e /proc/net/vlan/%s ]];then vconfig rem %s;fi"
         iface = "%s.%s" % (iface, v_id)
+        error.context("Remove the named vlan-device '%s'." % iface,
+                       logging.info)
         return session.cmd_status(rem_vlan_cmd % (iface, iface))
 
+
     def nc_transfer(src, dst):
         nc_port = utils_misc.find_free_port(1025, 5334, vm_ip[dst])
         listen_cmd = params.get("listen_cmd")
@@ -80,6 +83,37 @@ def run_vlan(test, params, env):
             raise error.TestFail("File transfered differ from origin")
         session[dst].cmd_output("rm -f receive")
 
+
+    def flood_ping(src, dst):
+        # we must use a dedicated session becuase the aexpect
+        # does not have the other method to interrupt the process in
+        # the guest rather than close the session.
+        error.context("Flood ping from %s interface %s to %s" % (vm[src].name,
+                      ifname[src], vlan_ip[dst]), logging.info)
+        session_flood = vm[src].wait_for_login(timeout=60)
+        utils_test.ping(vlan_ip[dst], flood=True,
+                          interface=ifname[src],
+                          session=session_flood, timeout=10)
+        session_flood.close()
+
+
+    vm = []
+    session = []
+    ifname = []
+    vm_ip = []
+    digest_origin = []
+    vlan_ip = ['', '']
+    ip_unit = ['1', '2']
+    subnet = params.get("subnet")
+    vlan_num = int(params.get("vlan_num"))
+    maximal = int(params.get("maximal"))
+    file_size = params.get("file_size")
+
+    vm.append(env.get_vm(params["main_vm"]))
+    vm.append(env.get_vm("vm2"))
+    for vm_ in vm:
+        vm_.verify_alive()
+
     for i in range(2):
         session.append(vm[i].wait_for_login(
             timeout=int(params.get("login_timeout", 360))))
@@ -102,11 +136,12 @@ def run_vlan(test, params, env):
         #stop firewall in vm
         session[i].cmd_output("/etc/init.d/iptables stop")
 
-        #load 8021q module for vconfig
+        error.context("load 8021q module in guest for vconfig", logging.info)
         session[i].cmd("modprobe 8021q")
 
     try:
         for i in range(2):
+            logging.info("Setup vlan environment in guest %s" % vm[i].name)
             for vlan_i in range(1, vlan_num+1):
                 add_vlan(session[i], vlan_i, ifname[i])
                 set_ip_vlan(session[i], vlan_i, "%s.%s.%s" %
@@ -116,13 +151,13 @@ def run_vlan(test, params, env):
         for vlan in range(1, vlan_num+1):
             logging.info("Test for vlan %s", vlan)
 
-            logging.info("Ping between vlans")
+            error.context("Ping test between vlans", logging.info)
             interface = ifname[0] + '.' + str(vlan)
             for vlan2 in range(1, vlan_num+1):
                 for i in range(2):
                     interface = ifname[i] + '.' + str(vlan)
                     dest = subnet +'.'+ str(vlan2)+ '.' + ip_unit[(i+1)%2]
-                    s, _ = utils_test.ping(dest, count=2,
+                    s, o = utils_test.ping(dest, count=2,
                                               interface=interface,
                                               session=session[i], timeout=30)
                     if ((vlan == vlan2) ^ (s == 0)):
@@ -132,35 +167,24 @@ def run_vlan(test, params, env):
             vlan_ip[0] = subnet + '.' + str(vlan) + '.' + ip_unit[0]
             vlan_ip[1] = subnet + '.' + str(vlan) + '.' + ip_unit[1]
 
-            logging.info("Flood ping")
-            def flood_ping(src, dst):
-                # we must use a dedicated session becuase the aexpect
-                # does not have the other method to interrupt the process in
-                # the guest rather than close the session.
-                session_flood = vm[src].wait_for_login(timeout=60)
-                utils_test.ping(vlan_ip[dst], flood=True,
-                                   interface=ifname[src],
-                                   session=session_flood, timeout=10)
-                session_flood.close()
-
             flood_ping(0, 1)
             flood_ping(1, 0)
 
-            logging.info("Transfering data through nc")
+            error.context("Transfering data through nc", logging.info)
             nc_transfer(0, 1)
             nc_transfer(1, 0)
 
     finally:
         for vlan in range(1, vlan_num+1):
+            logging.info("rem vlan: %s", vlan)
             rem_vlan(session[0], vlan, ifname[0])
             rem_vlan(session[1], vlan, ifname[1])
-            logging.info("rem vlan: %s", vlan)
 
     # Plumb/unplumb maximal number of vlan interfaces
     i = 1
     s = 0
     try:
-        logging.info("Testing the plumb of vlan interface")
+        error.context("Testing the plumb of vlan interface", logging.info)
         for i in range (1, maximal+1):
             add_vlan(session[0], i, ifname[0])
     finally: