[Sflow] Enable/disable container auto-restart based on configuration.

dockers/docker-sflow/Dockerfile.j2

@@ -29,7 +29,7 @@ RUN sed -ri '/^DAEMON_ARGS=""/c DAEMON_ARGS="-c /var/log/hsflowd.crash"' /etc/in
 
 COPY ["start.sh", "/usr/bin/"]
 COPY ["supervisord.conf", "/etc/supervisor/conf.d/"]
-COPY ["files/supervisor-proc-exit-listener", "/usr/bin"]
+COPY ["supervisor-proc-exit-listener", "/usr/bin"]
 COPY ["critical_processes", "/etc/supervisor"]
 
 ENTRYPOINT ["/usr/bin/supervisord"]

dockers/docker-sflow/supervisor-proc-exit-listener

@@ -0,0 +1,59 @@
+#!/usr/bin/env python
+
+import os
+import signal
+import sys
+import syslog
+import swsssdk
+
+from supervisor import childutils
+
+CONTAINER_NAME = 'sflow'
+
+# Contents of file should be the names of critical processes (as defined in
+# supervisor.conf file), one per line
+CRITICAL_PROCESSES_FILE = '/etc/supervisor/critical_processes'
+
+# This table in database contains the features for container and each 
+# feature for a row will be configured a state or number.
+CONTAINER_FEATURE_TABLE_NAME = 'CONTAINER_FEATURE'
+
+def main():
+    # Read the list of critical processes from a file
+    with open(CRITICAL_PROCESSES_FILE, 'r') as f:
+        critical_processes = [line.rstrip('\n') for line in f]
+
+    while True:
+        # Transition from ACKNOWLEDGED to READY
+        childutils.listener.ready()
+
+        line = sys.stdin.readline()
+        headers = childutils.get_headers(line)
+        payload = sys.stdin.read(int(headers['len']))
+
+        # Transition from READY to ACKNOWLEDGED
+        childutils.listener.ok()
+
+        # We only care about PROCESS_STATE_EXITED events
+        if headers['eventname'] == 'PROCESS_STATE_EXITED':
+            payload_headers, payload_data = childutils.eventdata(payload + '\n')
+
+            expected = int(payload_headers['expected'])
+            processname = payload_headers['processname']
+            groupname = payload_headers['groupname']
+
+            config_db = swsssdk.ConfigDBConnector()
+            config_db.connect()
+            docker_config = config_db.get_table(CONTAINER_FEATURE_TABLE_NAME)
+            if docker_config and docker_config.has_key(CONTAINER_NAME):
+                restart_feature = docker_config[CONTAINER_NAME].get('auto_restart')
+
+            # If auto-restart feature is enabled and a critical process exited unexpectedly, terminate supervisor
+            if restart_feature == 'enabled' and expected == 0 and (processname in critical_processes or groupname in critical_processes):
+                MSG_FORMAT_STR = "Process {} exited unxepectedly. Terminating supervisor..."
+                msg = MSG_FORMAT_STR.format(payload_headers['processname'])
+                syslog.syslog(syslog.LOG_INFO, msg)
+                os.kill(os.getppid(), signal.SIGTERM)
+
+if __name__ == "__main__":
+    main()

rules/docker-sflow.mk

@@ -33,4 +33,3 @@ $(DOCKER_SFLOW)_RUN_OPT += -v /host/warmboot:/var/warmboot
 $(DOCKER_SFLOW)_BASE_IMAGE_FILES += psample:/usr/bin/psample
 $(DOCKER_SFLOW)_BASE_IMAGE_FILES += sflowtool:/usr/bin/sflowtool
 $(DOCKER_SFLOW)_BASE_IMAGE_FILES += monit_sflow:/etc/monit/conf.d
-$(DOCKER_SFLOW)_FILES += $(SUPERVISOR_PROC_EXIT_LISTENER_SCRIPT)