[watermarkstat] Fix issue of fields overwritten before display (sonic…

…-net#862)

Fix the bug where the unicast/multicast queue watermark display was incorrect

- How I did it
Calculate the header list dynamically for PG and queue display
Display the correct queue numbers in the output instead of always starting the index from 0
Calculate the display position relative to the starting index

Signed-off-by: Neetha John <nejo@microsoft.com>

scripts/watermarkstat

@@ -15,9 +15,6 @@ from natsort import natsorted
 from tabulate import tabulate
 
 
-headerPg = ['Port', 'PG0', 'PG1', 'PG2', 'PG3', 'PG4', 'PG5', 'PG6', 'PG7']
-headerUc = ['Port', 'UC0', 'UC1', 'UC2', 'UC3', 'UC4', 'UC5', 'UC6', 'UC7']
-headerMc = ['Port', 'MC8', 'MC9', 'MC10', 'MC11', 'MC12', 'MC13', 'MC14', 'MC15']
 headerBufferPool = ['Pool', 'Bytes']
 
 
@@ -140,22 +137,22 @@ class Watermarkstat(object):
                                "obj_map" : self.port_pg_map,
                                "idx_func": self.get_pg_index,
                                "wm_name" : "SAI_INGRESS_PRIORITY_GROUP_STAT_XOFF_ROOM_WATERMARK_BYTES",
-                               "header"  : headerPg},
+                               "header_prefix": "PG"},
             "pg_shared"     : {"message" : "Ingress shared pool occupancy per PG:",
                                "obj_map" : self.port_pg_map,
                                "idx_func": self.get_pg_index,
                                "wm_name" : "SAI_INGRESS_PRIORITY_GROUP_STAT_SHARED_WATERMARK_BYTES",
-                               "header"  : headerPg},
+                               "header_prefix": "PG"},
             "q_shared_uni"  : {"message" : "Egress shared pool occupancy per unicast queue:",
                                "obj_map" : self.port_uc_queues_map,
                                "idx_func": self.get_queue_index,
                                "wm_name" : "SAI_QUEUE_STAT_SHARED_WATERMARK_BYTES",
-                               "header"  : headerUc},
+                               "header_prefix": "UC"},
             "q_shared_multi": {"message" : "Egress shared pool occupancy per multicast queue:",
                                "obj_map" : self.port_mc_queues_map,
                                "idx_func": self.get_queue_index,
                                "wm_name" : "SAI_QUEUE_STAT_SHARED_WATERMARK_BYTES",
-                               "header"  : headerMc},
+                               "header_prefix": "MC"},
             "buffer_pool"   : {"message": "Shared pool maximum occupancy:",
                                "wm_name": "SAI_BUFFER_POOL_STAT_WATERMARK_BYTES",
                                "header" : headerBufferPool}
@@ -177,28 +174,48 @@ class Watermarkstat(object):
 
         return pg_index
 
+    def build_header(self, wm_type):
+        if wm_type is None:
+            print >> sys.stderr, "Header info is not available!"
+            sys.exit(1)
+
+        self.header_list = ['Port']
+        header_map = wm_type["obj_map"]
+        single_key = header_map.keys()[0]
+        header_len = len(header_map[single_key])
+        min_idx = float("inf")
+
+        for name, counter_oid in header_map[single_key].items():
+            curr_idx = int(wm_type["idx_func"](counter_oid))
+            min_idx = min(min_idx, curr_idx)
+
+        self.min_idx = int(min_idx)
+        self.header_list += ["{}{}".format(wm_type["header_prefix"], idx) for idx in range(self.min_idx, self.min_idx + header_len)]
+
     def get_counters(self, table_prefix, port_obj, idx_func, watermark):
         """
             Get the counters from specific table.
         """
 
-        fields = ["0"] * 8
+        # header list contains the port name followed by the queues/pgs. fields is used to populate the queue/pg values
+        fields = ["0"]* (len(self.header_list) - 1)
 
         for name, obj_id in port_obj.items():
             full_table_id = table_prefix + obj_id
-            pos = int(idx_func(obj_id)) % len(fields)
+            idx = int(idx_func(obj_id))
+            pos = idx - self.min_idx
             counter_data = self.counters_db.get(self.counters_db.COUNTERS_DB, full_table_id, watermark)
             if counter_data is None:
                 fields[pos] = STATUS_NA
             elif fields[pos] != STATUS_NA:
                 fields[pos] = str(int(counter_data))
-        cntr = tuple(fields)
-        return cntr
+        return fields
 
     def print_all_stat(self, table_prefix, key):
         table = []
         type = self.watermark_types[key]
         if key == 'buffer_pool':
+            self.header_list = type['header']
             # Get stats for each buffer pool
             for buf_pool, bp_oid in natsorted(self.buffer_pool_name_to_oid_map.items()):
                 key = table_prefix + bp_oid
@@ -207,15 +224,18 @@ class Watermarkstat(object):
                     data = STATUS_NA
                 table.append((buf_pool, data))
         else:
+            self.build_header(type)
             # Get stat for each port
             for port in natsorted(self.counter_port_name_map):
+                row_data = list()
                 data = self.get_counters(table_prefix,
                                          type["obj_map"][port], type["idx_func"], type["wm_name"])
-                table.append((port, data[0], data[1], data[2], data[3],
-                              data[4], data[5], data[6], data[7]))
+                row_data.append(port)
+                row_data.extend(data)
+                table.append(tuple(row_data))
 
         print(type["message"])
-        print tabulate(table, type["header"], tablefmt='simple', stralign='right')
+        print tabulate(table, self.header_list, tablefmt='simple', stralign='right')
 
     def send_clear_notification(self, data):
         msg = json.dumps(data, separators=(',', ':'))