[docker-lldpd]: Various fixes (sonic-net#1650)

    * We don't need configure anything until we have interfaces created
    * Don't run lldpcli for a port, until a port is up and running
    * Remove lldpd socket before starting lldpd
    * Fix sample files for lldpd configuration
    * Another attempt to make the test working
    * Quick fix for lldpd paused after start bug

    RB=1294300
    G=lnos-reviewers
    R=ntrianta,pmao,rmolina,sfardeen,zxu
    A=

dockers/docker-lldp-sv2/lldpd.conf.j2

@@ -1,6 +1,3 @@
 {% if MGMT_INTERFACE %}
 configure ports eth0 lldp portidsubtype local {{ MGMT_INTERFACE.keys()[0][0] }}
 {% endif %}
-{% for local_port in DEVICE_NEIGHBOR %}
-configure ports {{ local_port }} lldp portidsubtype local {{ PORT[local_port]['alias'] }} description {{ DEVICE_NEIGHBOR[local_port]['name'] }}:{{ DEVICE_NEIGHBOR[local_port]['port'] }}
-{% endfor %}

dockers/docker-lldp-sv2/lldpmgrd

@@ -20,6 +20,7 @@ try:
     import subprocess
     import sys
     import syslog
+    import os.path
     from swsscommon import swsscommon
 except ImportError as err:
     raise ImportError("%s - required module not found" % str(err))
@@ -70,6 +71,19 @@ def signal_handler(sig, frame):
     else:
         log_warning("Caught unhandled signal '" + sig + "'")
 
+# ========================== Helpers ==================================
+
+def is_port_up(port_name):
+    filename = "/sys/class/net/%s/operstate" % port_name
+    if not os.path.exists(filename):
+        return False
+
+    with open(filename) as fp:
+        state = fp.read()
+        if 'up' in state:
+            return True
+        else:
+            return False
 
 # ============================== Classes ==============================
 
@@ -161,6 +175,11 @@ class LldpManager(object):
         to_delete = []
 
         for (port_name, cmd) in self.pending_cmds.iteritems():
+            if not is_port_up(port_name):
+                # it doesn't make any sense to configure lldpd if the target port is unavailable
+                # let's postpone the command for the next iteration
+                continue
+
             log_debug("Running command: '{}'".format(cmd))
 
             proc = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)

dockers/docker-lldp-sv2/start.sh

@@ -6,8 +6,32 @@ mkdir -p /var/sonic
 echo "# Config files managed by sonic-config-engine" > /var/sonic/config_status
 
 rm -f /var/run/rsyslogd.pid
+rm -f /var/run/lldpd.socket
 
 supervisorctl start rsyslogd
 supervisorctl start lldpd
 supervisorctl start lldp-syncd
 supervisorctl start lldpmgrd
+
+# Current lldpd version has a bug.
+# When lldpd starts it is in the pause state by default
+# But then it execute 'lldpcli resume' to configure and unpause itself.
+# When lldpd execute lldpcli, it doesn't check the return code
+# Sometimes lldpcli returns failure, but lldpd doesn't catch it
+# and keeps working paused and unconfigured
+#
+# The fix below addresses the issue.
+#
+
+# wait until lldpd started
+until [[ -e /var/run/lldpd.socket ]];
+do
+    sleep 1;
+done
+
+# Manually try to resume lldpd, until it's successful
+while /bin/true;
+do
+    lldpcli -u /var/run/lldpd.socket -c /etc/lldpd.conf -c /etc/lldpd.d resume > /dev/null && break
+    sleep 1
+done

src/sonic-config-engine/tests/sample_output/lldpd.conf

@@ -1,6 +1,2 @@
 configure ports eth0 lldp portidsubtype local eth0
-configure ports Ethernet112 lldp portidsubtype local fortyGigE0/112 description ARISTA01T1:Ethernet1/1
-configure ports Ethernet116 lldp portidsubtype local fortyGigE0/116 description ARISTA02T1:Ethernet1/1
-configure ports Ethernet120 lldp portidsubtype local fortyGigE0/120 description ARISTA03T1:Ethernet1/1
-configure ports Ethernet124 lldp portidsubtype local fortyGigE0/124 description ARISTA04T1:Ethernet1/1