Utils for session logging test cases and SLO

    corresponding review for the test cases is https://review.opencontrail.org/#/c/38724/

Change-Id: Id1c5f6c153aa17374eb0f5eb07838e350583c4bd
Partial-bug: #1741461
Partial-bug: #1741836
Partial-bug: #1740493

common/flow_tests/base.py

@@ -1,6 +1,8 @@
 import re
 
 from common.vrouter.base import BaseVrouterTest
+from tcutils.util import get_random_name, retry
+import random
 
 class FlowTestBase(BaseVrouterTest):
 
@@ -32,6 +34,37 @@ def get_flows_exported(self, agent_name, last="1m"):
             return None
     # end get_flows_exported
 
+    def get_sessions_exported(self, node_ip, start_time, end_time):
+        '''
+            Gets the total sessions exported within mentioned time range
+            by a particular vrouter node
+        '''
+        table_name = "SessionSeriesTable"
+        select_fields = ["forward_action", "sample_count", "vrouter_ip"]
+
+        sessions_exported = 0
+        res_s = self.ops_inspect[self.inputs.collector_ips[0]].post_query(
+            table_name, start_time=start_time, end_time=end_time,
+            select_fields=select_fields, session_type='server')
+
+        res_c = self.ops_inspect[self.inputs.collector_ips[0]].post_query(
+            table_name, start_time=start_time, end_time=end_time,
+            select_fields=select_fields, session_type='client')
+
+        self.logger.debug("Server sessions: %s\n Client sessions: %s" % (
+            res_s, res_c))
+        for record in res_s:
+            if node_ip == record['vrouter_ip']:
+                sessions_exported += record['sample_count']
+        for record in res_c:
+            if node_ip == record['vrouter_ip']:
+                sessions_exported += record['sample_count']
+        if not sessions_exported:
+            self.logger.debug("No sessions exported from the vrouter %s"\
+                " in last %s seconds" % (node_ip, last))
+
+        return sessions_exported
+
     def setup_flow_export_rate(self, value):
         ''' Set flow export rate and handle the cleanup
         '''
@@ -41,3 +74,91 @@ def setup_flow_export_rate(self, value):
         self.addCleanup(vnc_lib_fixture.set_flow_export_rate, current_rate)
     # end setup_flow_export_rate
 
+    def enable_logging_on_compute(self, node_ip, log_type,
+            restart_on_cleanup=True):
+        ''' Enable local logging on compute node
+            log_type: can be agent/syslog
+        '''
+        container_name = 'agent'
+        conf_file = '/etc/contrail/contrail-vrouter-agent.conf'
+        service_name = 'contrail-vrouter-agent'
+        #Take backup of original conf file to revert back later
+        conf_file_backup = '/tmp/'+ get_random_name(conf_file.split('/')[-1])
+        cmd = 'cp %s %s' % (conf_file, conf_file_backup)
+        status = self.inputs.run_cmd_on_server(node_ip, cmd,
+            container=container_name)
+
+        self.addCleanup(
+            self.restore_default_config_file, conf_file,
+            conf_file_backup, service_name, node_ip, container_name,
+            restart_on_cleanup)
+
+        oper = 'set'
+        section = 'DEFAULT'
+        self.update_contrail_conf(service_name, oper, section,
+            'log_flow', 1, node_ip, container_name)
+        self.update_contrail_conf(service_name, oper, section,
+            'log_local', 1, node_ip, container_name)
+        self.update_contrail_conf(service_name, oper, section,
+            'log_level', 'SYS_INFO', node_ip, container_name)
+
+        if log_type == 'syslog':
+            self.update_contrail_conf(service_name, oper, section,
+                'use_syslog', 1, node_ip, container_name)
+
+        self.inputs.restart_service(service_name, [node_ip],
+            container=container_name, verify_service=True)
+    #end enable_logging_on_compute
+
+    def restore_default_config_file(self, conf_file, conf_file_backup,
+            service_name, node_ip, container=None, restart_on_cleanup=True):
+        '''Restore config file from conf_file_backup
+            conf_file: full path of config file location
+            conf_file_backup: full path of backup config file from where it will be restored
+            service_name: service name
+        '''
+        cmd = "mv %s %s" % (conf_file_backup, conf_file)
+        output = self.inputs.run_cmd_on_server(
+            node_ip,
+            cmd,
+            container=container)
+
+        if restart_on_cleanup:
+            self.inputs.restart_service(service_name, [node_ip],
+                container=container, verify_service=True)
+
+    @retry(delay=1, tries=10)
+    def search_session_in_log(self, log_file, node_ip, session_log,
+            object_name='SessionEndpointObject'):
+        '''Search session in log file on node node_ip'''
+
+        container_name = 'agent'
+        username = self.inputs.host_data[node_ip]['username']
+        password = self.inputs.host_data[node_ip]['password']
+        cmd = 'grep -a %s %s | grep -aP "%s"' % (object_name, log_file,
+            session_log)
+        output = self.inputs.run_cmd_on_server(
+            node_ip, cmd, username, password, container=container_name)
+
+        if not output:
+            return False, None
+        else:
+            self.logger.debug("\nSession Expected: %s, \nSession found: %s",
+                session_log, output)
+            return True, output
+
+    def search_session_in_agent_log(self, node_ip, session_log):
+        '''Search session in agent log file'''
+
+        log_file = '/var/log/contrail/contrail-vrouter-agent.log*'
+        object_name = 'SessionEndpointObject'
+        return self.search_session_in_log(log_file, node_ip, session_log,
+            object_name=object_name)
+
+    def search_session_in_syslog(self, node_ip, session_log):
+        '''Search session in syslog'''
+
+        log_file = '/var/log/syslog*'
+        object_name = 'SessionData'
+        return self.search_session_in_log(log_file, node_ip, session_log,
+            object_name=object_name)