[Portstat]: Add -p option to support portstat timer (#16)

scripts/portstat

@@ -15,6 +15,7 @@ import os.path
 import re
 import subprocess
 import sys
+import time
 
 from collections import namedtuple, OrderedDict
 from tabulate import tabulate
@@ -204,6 +205,68 @@ def parse_bcmcmd_ps(bcmcmd_output):
     bcmcmd_lines = bcmcmd_output.split("\n")
 
 
+def get_cnstat():
+    """
+          Get the cnstat from netstat.
+    """
+    try:
+        bcmcmd_output = subprocess.Popen(([BCMCMD_PATH,
+                                           'show counters changed same nz']),
+                                         stdout=subprocess.PIPE,
+                                         shell=False).communicate()[0]
+    except EnvironmentError as e:
+        print e, e.errno
+        sys.exit(e.errno)
+
+    bcm_dict = parse_bcmcmd_output(bcmcmd_output)
+
+    try:
+        netstat_out = subprocess.Popen(([NETSTAT_PATH, '-i']),
+                                       stdout=subprocess.PIPE,
+                                       shell=False).communicate()[0]
+    except EnvironmentError as e:
+        print e, e.errno
+        sys.exit(e.errno)
+
+    netstat_lines = netstat_out.split("\n")
+
+    # Since netstat -i returns some stats as 32-bits, get full 64-bit
+    # stats from /prov/net/dev and display only the 64-bit stats.
+    try:
+        proc_out = subprocess.Popen(([CAT_PATH, '/proc/net/dev']),
+                                    stdout=subprocess.PIPE,
+                                    shell=False).communicate()[0]
+    except EnvironmentError as e:
+        print e, e.errno
+        sys.exit(e.errno)
+
+    proc = {}
+    for line in proc_out.split("\n"):
+        parsed = re.findall("\s*([^ ]+):(.*)", line)
+        if not parsed:
+            continue
+        iface, stats = parsed[0]
+        proc[iface] = stats.split()
+
+    # Build a dictionary of the stats
+    cnstat_dict = OrderedDict()
+
+    cnstat_dict['time'] = datetime.datetime.now()
+
+    # We skip the first 2 lines since they contain no interface information
+    for i in range(2, len(netstat_lines) - 1):
+        netstats = netstat_lines[i].split()
+        if ":" in netstats[0]:
+            continue    # Skip aliased interfaces
+        if ("eth" in netstats[0] or "lo" in netstats[0] or "docker" in netstats[0] or
+                "Vlan" in netstats[0] or "PortChannel" in netstats[0]):
+            continue    # Skip these types of interfaces
+        else:
+            cnstat_dict.update(cnstat_create_bcm_element(i, netstats, bcm_dict[netstats[0]]))
+
+
+    return cnstat_dict
+
 def cnstat_diff_print(cnstat_new_dict, cnstat_old_dict, use_json):
     table = []
 
@@ -261,13 +324,15 @@ Examples:
   portstat -d -t test
   portstat
   portstat -r
+  portstat -p 20
 """)
     parser.add_argument('-c', '--clear', action='store_true', help='Copy & clear stats')
     parser.add_argument('-d', '--delete', action='store_true', help='Delete saved stats, either the uid or the specified tag')
     parser.add_argument('-D', '--delete-all', action='store_true', help='Delete all saved stats')
     parser.add_argument('-j', '--json', action='store_true', help='Display in JSON format')
     parser.add_argument('-r', '--raw', action='store_true', help='Raw stats (unmodified output of netstat)')
     parser.add_argument('-t', '--tag', type=str, help='Save stats with name TAG', default=None)
+    parser.add_argument('-p', '--period', type=int, help='Display stats over a specified period (in seconds).', default=0)
     args = parser.parse_args()
 
     save_fresh_stats = args.clear
@@ -277,6 +342,7 @@ Examples:
     raw_stats = args.raw
     tag_name = args.tag
     uid = str(os.getuid())
+    wait_time_in_seconds = args.period
 
     if not os.geteuid() == 0:
         raise RuntimeError("must be root to run")
@@ -311,45 +377,13 @@ Examples:
             if os.listdir(cnstat_dir) == []:
                 os.rmdir(cnstat_dir)
             sys.exit(0)
+
+    cnstat_dict = get_cnstat()
 
-    try:
-        bcmcmd_output = subprocess.Popen(([BCMCMD_PATH,
-                                           'show counters changed same nz']),
-                                         stdout=subprocess.PIPE,
-                                         shell=False).communicate()[0]
-    except EnvironmentError as e:
-        print e, e.errno
-        sys.exit(e.errno)
-
-    bcm_dict = parse_bcmcmd_output(bcmcmd_output)
-
-    try:
-        netstat_out = subprocess.Popen(([NETSTAT_PATH, '-i']),
-                                       stdout=subprocess.PIPE,
-                                       shell=False).communicate()[0]
-    except EnvironmentError as e:
-        print e, e.errno
-        sys.exit(e.errno)
-
-    netstat_lines = netstat_out.split("\n")
-
-    # Since netstat -i returns some stats as 32-bits, get full 64-bit
-    # stats from /prov/net/dev and display only the 64-bit stats.
-    try:
-        proc_out = subprocess.Popen(([CAT_PATH, '/proc/net/dev']),
-                                    stdout=subprocess.PIPE,
-                                    shell=False).communicate()[0]
-    except EnvironmentError as e:
-        print e, e.errno
-        sys.exit(e.errno)
-
-    proc = {}
-    for line in proc_out.split("\n"):
-        parsed = re.findall("\s*([^ ]+):(.*)", line)
-        if not parsed:
-            continue
-        iface, stats = parsed[0]
-        proc[iface] = stats.split()
+    # Now decide what information to display
+    if raw_stats:
+        cnstat_print(cnstat_dict, use_json)
+        sys.exit(0)
 
     # At this point, either we'll create a file or open an existing one.
     if not os.path.exists(cnstat_dir):
@@ -359,26 +393,6 @@ Examples:
             print e.errno, e
             sys.exit(1)
 
-    # Build a dictionary of the stats
-    cnstat_dict = OrderedDict()
-
-    cnstat_dict['time'] = datetime.datetime.now()
-
-    # We skip the first 2 lines since they contain no interface information
-    for i in range(2, len(netstat_lines) - 1):
-        netstats = netstat_lines[i].split()
-        if ":" in netstats[0]:
-            continue    # Skip aliased interfaces
-        if ("eth" in netstats[0] or "lo" in netstats[0] or "docker" in netstats[0] or
-                "Vlan" in netstats[0] or "PortChannel" in netstats[0]):
-            continue    # Skip these types of interfaces
-        else:
-            cnstat_dict.update(cnstat_create_bcm_element(i, netstats, bcm_dict[netstats[0]]))
-
-    # Now decide what information to display
-    if raw_stats:
-        cnstat_print(cnstat_dict, use_json)
-        sys.exit(0)
 
     if save_fresh_stats:
         try:
@@ -388,20 +402,25 @@ Examples:
         else:
             print "Cleared counters"
             sys.exit(0)
-
-    cnstat_cached_dict = OrderedDict()
-
-    if os.path.isfile(cnstat_fqn_file):
-        try:
-            cnstat_cached_dict = pickle.load(open(cnstat_fqn_file, 'r'))
-            print "Last cached time was " + str(cnstat_cached_dict.get('time'))
-            cnstat_diff_print(cnstat_dict, cnstat_cached_dict, use_json)
-        except IOError as e:
-            print e.errno, e
-    else:
-        if tag_name:
-            print "\nFile '%s' does not exist" % cnstat_fqn_file
-            print "Did you run 'portstat -c -t %s' to record the counters via tag %s?\n" % (tag_name, tag_name)
+
+    if wait_time_in_seconds == 0:
+        cnstat_cached_dict = OrderedDict()
+        if os.path.isfile(cnstat_fqn_file):
+            try:
+                cnstat_cached_dict = pickle.load(open(cnstat_fqn_file, 'r'))
+                print "Last cached time was " + str(cnstat_cached_dict.get('time'))
+                cnstat_diff_print(cnstat_dict, cnstat_cached_dict, use_json)
+            except IOError as e:
+                print e.errno, e
         else:
-            cnstat_print(cnstat_dict, use_json)
+            if tag_name:
+                print "\nFile '%s' does not exist" % cnstat_fqn_file
+                print "Did you run 'portstat -c -t %s' to record the counters via tag %s?\n" % (tag_name, tag_name)
+            else:
+                cnstat_print(cnstat_dict, use_json)
+    else:
+        #wait for the specified time and then gather the new stats and output the difference.
+        time.sleep(wait_time_in_seconds)
+        cnstat_new_dict = get_cnstat()
+        cnstat_diff_print(cnstat_new_dict, cnstat_dict, use_json)