Discover config file for mongodb

mongodb 2.6 uses diff config file as opposed to
lower versions. Given diff file candidates code
selects config file that is available

Change-Id: I8fe9eea39a47aa890834a0c55e98c062f9b9fd15
Closes-Bug: #1368468

3 files changed, 21 insertions, 12 deletions

diff --git a/trove/guestagent/common/operating_system.py b/trove/guestagent/common/operating_system.py
index 9223bd2b..1f90f591 100644
--- a/trove/guestagent/common/operating_system.py
+++ b/trove/guestagent/common/operating_system.py
@@ -29,6 +29,12 @@ def get_os():
         return DEBIAN
 
 
+def file_discovery(file_candidates):
+    for file in file_candidates:
+        if os.path.isfile(file):
+            return file
+
+
 def service_discovery(service_candidates):
     """
     This function discovering how to start, stop, enable, disable service
diff --git a/trove/guestagent/datastore/mongodb/service.py b/trove/guestagent/datastore/mongodb/service.py
index 31016e3a..2f3832bd 100644
--- a/trove/guestagent/datastore/mongodb/service.py
+++ b/trove/guestagent/datastore/mongodb/service.py
@@ -30,6 +30,8 @@ from trove.openstack.common.gettextutils import _
 
 LOG = logging.getLogger(__name__)
 CONF = cfg.CONF
+CONFIG_FILE = (operating_system.
+               file_discovery(system.CONFIG_CANDIDATES))
 
 
 class MongoDBApp(object):
@@ -174,11 +176,10 @@ class MongoDBApp(object):
                     t.write(config_contents)
 
                 LOG.info(_("Moving %(a)s to %(b)s")
-                         % {'a': system.TMP_CONFIG,
-                            'b': system.CONFIG})
+                         % {'a': system.TMP_CONFIG, 'b': CONFIG_FILE})
                 utils.execute_with_timeout("mv",
                                            system.TMP_CONFIG,
-                                           system.CONFIG,
+                                           CONFIG_FILE,
                                            run_as_root=True,
                                            root_helper="sudo")
             except Exception:
@@ -189,10 +190,10 @@ class MongoDBApp(object):
 
     def _read_config(self):
         try:
-            with open(system.CONFIG, 'r') as f:
+            with open(CONFIG_FILE, 'r') as f:
                 return f.read()
         except IOError:
-            LOG.info(_("Config file %s not found") % system.CONFIG)
+            LOG.info(_("Config file %s not found") % CONFIG_FILE)
             return ''
 
     def _delete_config_parameters(self, config_contents, parameters):
@@ -235,10 +236,11 @@ class MongoDBApp(object):
         self.start_db_with_conf_changes(contents)
 
     def write_mongos_upstart(self):
-
+        upstart_contents = (system.MONGOS_UPSTART_CONTENTS.
+                            format(config_file_placeholder=CONFIG_FILE))
         LOG.info(_("Writing %s") % system.TMP_MONGOS_UPSTART)
         with open(system.TMP_MONGOS_UPSTART, 'w') as t:
-            t.write(system.MONGOS_UPSTART_CONTENTS)
+            t.write(upstart_contents)
 
         LOG.info(_("Moving %(a)s to %(b)s")
                  % {'a': system.TMP_MONGOS_UPSTART,
@@ -335,7 +337,7 @@ class MongoDbAppStatus(service.BaseDbStatus):
         if self.is_config_server is None:
             try:
                 cmd = ("grep '^configsvr[ \t]*=[ \t]*true$' %s"
-                       % system.CONFIG)
+                       % CONFIG_FILE)
                 utils.execute_with_timeout(cmd, shell=True)
                 self.is_config_server = True
             except exception.ProcessExecutionError:
@@ -346,7 +348,7 @@ class MongoDbAppStatus(service.BaseDbStatus):
         if self.is_query_router is None:
             try:
                 cmd = ("grep '^configdb[ \t]*=.*$' %s"
-                       % system.CONFIG)
+                       % CONFIG_FILE)
                 utils.execute_with_timeout(cmd, shell=True)
                 self.is_query_router = True
             except exception.ProcessExecutionError:
diff --git a/trove/guestagent/datastore/mongodb/system.py b/trove/guestagent/datastore/mongodb/system.py
index efe5d750..30324730 100644
--- a/trove/guestagent/datastore/mongodb/system.py
+++ b/trove/guestagent/datastore/mongodb/system.py
@@ -21,7 +21,7 @@ MONGODB_MOUNT_POINT = "/var/lib/mongodb"
 CMD_STATUS = "mongostat --host %s -n 1 | grep connected"
 
 TMP_CONFIG = "/tmp/mongodb.conf.tmp"
-CONFIG = "/etc/mongodb.conf"
+CONFIG_CANDIDATES = ["/etc/mongodb.conf", "/etc/mongod.conf"]
 MONGOS_UPSTART = "/etc/init/mongos.conf"
 TMP_MONGOS_UPSTART = "/tmp/mongos.conf.tmp"
 MONGOS_SERVICE_CANDIDATES = ["mongos"]
@@ -31,7 +31,8 @@ FIND_PID = "ps xau | grep 'mongo[ds]'"
 TIME_OUT = 1000
 
 INIT_EXEC_MONGOS = ("start-stop-daemon --start --quiet --chuid mongodb "
-                    "--exec  /usr/bin/mongos -- --config %s" % CONFIG)
+                    "--exec  /usr/bin/mongos -- "
+                    "--config {config_file_placeholder}")
 
 MONGOS_UPSTART_CONTENTS = """pre-start script
     mkdir -p /var/log/mongodb/
@@ -44,6 +45,6 @@ script
   ENABLE_MONGOS="yes"
   if [ -f /etc/default/mongos ]; then . /etc/default/mongos; fi
   if [ "x$ENABLE_MONGOS" = "xyes" ]; then exec %s; fi
-end script""" % INIT_EXEC_MONGOS
+end script """ % INIT_EXEC_MONGOS
 
 PACKAGER = pkg.Package()