Merge pull request sonic-net#64 from judyjoseph/multi_asic_ledd_xcvr

* platform daemon (Xcvrd, Ledd) changes for multi asic platform
  * Updates in ledd daemon to use namespaces and get the namespace from selector object.
  * Updates to xcvrd daemon to use the asic_id in talking to the right DB.
  * Updated based on new sonic-py-common API's
  * Invoke initializeGlobalConfig() in the SfpUpdate/DomInfoUpdate processes as well.

sonic-ledd/scripts/ledd

@@ -10,6 +10,8 @@ try:
     import sys
 
     from sonic_py_common import daemon_base
+    from sonic_py_common import multi_asic
+    from sonic_py_common.interface import backplane_prefix
     from swsscommon import swsscommon
 except ImportError as e:
     raise ImportError (str(e) + " - required module not found")
@@ -35,6 +37,9 @@ SELECT_TIMEOUT = 1000
 
 LEDUTIL_LOAD_ERROR = 1
 
+# The empty namespace refers to linux host namespace.
+EMPTY_NAMESPACE = ''
+
 class DaemonLedd(daemon_base.DaemonBase):
 
     # Run daemon
@@ -65,15 +70,24 @@ class DaemonLedd(daemon_base.DaemonBase):
             self.log_error("Failed to load ledutil: %s" % (str(e)), True)
             sys.exit(LEDUTIL_LOAD_ERROR)
 
-        # Open a handle to the Application database
-        appl_db = daemon_base.db_connect("APPL_DB")
+        # Load the namespace details first from the database_global.json file.
+        swsscommon.SonicDBConfig.initializeGlobalConfig()
+
+        # Get the namespaces in the platform. For multi-asic devices we get the namespaces
+        # of front-end ascis which have front-panel interfaces.
+        namespaces = multi_asic.get_front_end_namespaces()
 
         # Subscribe to PORT table notifications in the Application DB
+        appl_db, sst = {}, {}
         sel = swsscommon.Select()
-        sst = swsscommon.SubscriberStateTable(appl_db, swsscommon.APP_PORT_TABLE_NAME)
-        sel.addSelectable(sst)
 
-        # Listen indefinitely for changes to the PORT table in the Application DB
+        for namespace in namespaces:
+            # Open a handle to the Application database, in all namespaces
+            appl_db[namespace] = daemon_base.db_connect("APPL_DB", namespace=namespace)
+            sst[namespace] = swsscommon.SubscriberStateTable(appl_db[namespace], swsscommon.APP_PORT_TABLE_NAME)
+            sel.addSelectable(sst[namespace])
+
+        # Listen indefinitely for changes to the PORT table in the Application DB's
         while True:
             # Use timeout to prevent ignoring the signals we want to handle
             # in signal_handler() (e.g. SIGTERM for graceful shutdown)
@@ -86,17 +100,20 @@ class DaemonLedd(daemon_base.DaemonBase):
                 self.log_warning("sel.select() did not  return swsscommon.Select.OBJECT")
                 continue
 
-            (key, op, fvp) = sst.pop()
-
-            # TODO: Once these flag entries have been removed from the DB,
-            # we can remove this check
-            if key in ["PortConfigDone", "PortInitDone"]:
-                continue
+            # Get the namespace from the selectable object and use it to index the SubscriberStateTable handle.
+            ns=c.getDbNamespace()
+            (key, op, fvp) = sst[ns].pop()
+            if fvp:
+                # TODO: Once these flag entries have been removed from the DB,
+                # we can remove this check
+                if key in ["PortConfigDone", "PortInitDone"]:
+                    continue
 
-            fvp_dict = dict(fvp)
+                fvp_dict = dict(fvp)
 
-            if op == "SET" and "oper_status" in fvp_dict:
-                led_control.port_link_state_change(key, fvp_dict["oper_status"])
+                if op == "SET" and "oper_status" in fvp_dict:
+                    if not key.startswith(backplane_prefix()):
+                        led_control.port_link_state_change(key, fvp_dict["oper_status"])
 
         return 1