tests: Adding start and stop topology

Signed-off-by: Ashish Pant <ashish12pant@gmail.com>

Adding methods for staring and stopping routers in topology

tests/topotests/lib/common_config.py

@@ -18,6 +18,90 @@
 # OF THIS SOFTWARE.
 #
 
+import os
+
+from lib.topolog import logger, logger_config
+from lib.topogen import TopoRouter
+
+
+# Creating tmp dir with testsuite name to avoid conflict condition when
+# multiple testsuites run together. All temporary files would be created
+# in this dir and this dir would be removed once testsuite run is
+# completed
+LOGDIR = "/tmp/topotests/"
+TMPDIR = None
+
+
+def start_topology(tgen):
+    """
+    Starting topology, create tmp files which are loaded to routers
+    to start deamons and then start routers
+    * `tgen`  : topogen object
+    """
+
+    global TMPDIR
+    # Starting topology
+    tgen.start_topology()
+
+    # Starting deamons
+    router_list = tgen.routers()
+    TMPDIR = os.path.join(LOGDIR, tgen.modname)
+
+    # Deleting temporary created dir if exists
+    if os.path.exists("{}".format(TMPDIR)):
+        os.system("rm -rf {}".format(TMPDIR))
+
+    # Create testsuite named temporary dir to save
+    # tmp files
+    os.mkdir("{}".format(TMPDIR))
+
+    for rname, router in router_list.iteritems():
+        try:
+            os.chdir(TMPDIR)
+
+            # Creating rouer named dir and empty zebra.conf bgpd.conf files
+            # inside the current directory
+            os.mkdir("{}".format(rname))
+            os.system("chmod -R go+rw {}".format(rname))
+            os.chdir("{}/{}".format(TMPDIR, rname))
+            os.system("touch zebra.conf bgpd.conf")
+
+        except IOError as (errno, strerror):
+            logger.error("I/O error({0}): {1}".format(errno, strerror))
+
+        # Loading empty zebra.conf file to router, to start the zebra deamon
+        router.load_config(
+            TopoRouter.RD_ZEBRA,
+            "{}/{}/zebra.conf".format(TMPDIR, rname)
+            # os.path.join(TMPDIR, "{}/zebra.conf".format(rname))
+        )
+        # Loading empty bgpd.conf file to router, to start the bgp deamon
+        router.load_config(
+            TopoRouter.RD_BGP,
+            "{}/{}/bgpd.conf".format(TMPDIR, rname)
+            # os.path.join(TMPDIR, "{}/bgpd.conf".format(rname))
+        )
+
+    # Starting routers
+    logger.info("Starting all routers once topology is created")
+    tgen.start_router()
+
+
+def stop_topology(tgen):
+    """
+    It will stop topology and remove temporary dirs and files.
+    * `tgen`  : topogen object
+    """
+
+    # This function tears down the whole topology.
+    tgen.stop_topology()
+
+    # Removing tmp dirs and files, once the topology is deleted
+    try:
+        os.system("rm -rf {}".format(TMPDIR))
+    except IOError as (errno, strerror):
+        logger.error("I/O error({0}): {1}".format(errno, strerror))
+
 
 def number_to_row(routerName):
     """
@@ -34,4 +118,5 @@ def number_to_column(routerName):
     Calculation based on name a0 = columnn 0, a1 = column 0, b2= column 1,
     z23 = column 26 etc
     """
-    return ord(routerName[0]) - 97
+    return ord(routerName[0]) - 97
+