Make datetime format in log files to be configurable

This patch adds possibility to configure in Tobiko what is the
format of the OpenStack services log lines format and how to
parse it to get date time from lines.

Change-Id: Ibe2c92e2a1dfbbd23f00cf1c635f9799a5c3e613

tobiko/openstack/topology/_neutron.py

@@ -22,6 +22,7 @@ from oslo_log import log
 
 import tobiko
 from tobiko.openstack import neutron
+from tobiko.openstack.topology import _config
 from tobiko.openstack.topology import _topology
 from tobiko.shell import files
 
@@ -47,10 +48,13 @@ class NeutronNovaCommonReader(tobiko.SharedFixture):
     log_digger: files.MultihostLogFileDigger
     groups: typing.List[str]
     message_pattern: str
-    datetime_pattern = re.compile(r'(\d{4}-\d{2}-\d{2} [0-9:.]+) .+')
+    datetime_pattern: typing.Pattern
+    config = tobiko.required_setup_fixture(_config.OpenStackTopologyConfig)
     service_name = neutron.SERVER
 
     def setup_fixture(self):
+        self.datetime_pattern = re.compile(
+            self.config.conf.log_datetime_pattern)
         self.log_digger = self.useFixture(
             _topology.get_log_file_digger(
                 service_name=self.service_name,

tobiko/openstack/topology/config.py

@@ -35,6 +35,10 @@ OPTIONS = [
                default=None,
                choices=['', '4', '6'],
                help="Limit connectivity to cloud to IPv4 o IPv6"),
+    cfg.StrOpt('log_datetime_pattern',
+               default=r"(\d{4}-\d{2}-\d{2} [0-9:.]+) .+",
+               help="Regex to be used to parse date and time from "
+                    "the OpenStack services' log lines. "),
 ]