tuned-adm: Print log excerpt when changing profile

Print messages logged during a profile switch to stderr (this affects
the "profile" and "auto_profile" commands). By default messages with
log level ERROR and higher are printed. This can be changed using the
--loglevel command line option. Valid values are debug, info, warn,
error, console, none ('none' can be used to disable the log printing).
E.g.:
tuned-adm --loglevel info profile powersave

Log printing cannot be used when --async is used.

Resolves: rhbz#1538745

Signed-off-by: Ondřej Lysoněk <olysonek@redhat.com>

TODO

@@ -5,3 +5,6 @@
   disconnects from DBus.
 * Use only one timer for destroying log handlers at a time. Create a new
   timer as necessary when the old timer fires.
+* Handle signals in tuned-adm so that the log_capture_finish() DBus call
+  is called even if we receive a signal. This may require some rewriting
+  of tuned-adm.

tuned-adm.py

@@ -37,6 +37,15 @@ def check_positive(value):
 		raise argparse.ArgumentTypeError("%s has to be >= 0" % value)
 	return val
 
+def check_log_level(value):
+	try:
+		return consts.CAPTURE_LOG_LEVELS[value.lower()]
+	except KeyError:
+		levels = ", ".join(consts.CAPTURE_LOG_LEVELS.keys())
+		raise argparse.ArgumentTypeError(
+				"Invalid log level: %s. Valid log levels: %s."
+				% (value, levels))
+
 if __name__ == "__main__":
 	config = GlobalConfig()
 	parser = argparse.ArgumentParser(description="Manage tuned daemon.")
@@ -44,6 +53,13 @@ if __name__ == "__main__":
 	parser.add_argument("--debug", "-d", action="store_true", help="show debug messages")
 	parser.add_argument("--async", "-a", action="store_true", help="with dbus do not wait on commands completion and return immediately")
 	parser.add_argument("--timeout", "-t", default = consts.ADMIN_TIMEOUT, type = check_positive, help="with sync operation use specific timeout instead of the default %d second(s)" % consts.ADMIN_TIMEOUT)
+	levels = ", ".join(consts.CAPTURE_LOG_LEVELS.keys())
+	help = "level of log messages to capture (one of %s). Default: %s" \
+			% (levels, consts.CAPTURE_LOG_LEVEL)
+	parser.add_argument("--loglevel", "-l",
+			default = consts.CAPTURE_LOG_LEVEL,
+			type = check_log_level,
+			help = help)
 
 	subparsers = parser.add_subparsers()
 
@@ -85,12 +101,13 @@ if __name__ == "__main__":
 	async = options.pop("async")
 	timeout = options.pop("timeout")
 	action_name = options.pop("action")
+	log_level = options.pop("loglevel")
 	result = False
 
 	dbus = config.get_bool(consts.CFG_DAEMON, consts.CFG_DEF_DAEMON)
 
 	try:
-		admin = tuned.admin.Admin(dbus, debug, async, timeout)
+		admin = tuned.admin.Admin(dbus, debug, async, timeout, log_level)
 
 		result = admin.action(action_name, **options)
 	except:

tuned/admin/admin.py

@@ -11,9 +11,12 @@ import sys
 import errno
 import time
 import threading
+import logging
 
 class Admin(object):
-	def __init__(self, dbus = True, debug = False, async = False, timeout = consts.ADMIN_TIMEOUT):
+	def __init__(self, dbus = True, debug = False, async = False,
+			timeout = consts.ADMIN_TIMEOUT,
+			log_level = logging.ERROR):
 		self._dbus = dbus
 		self._debug = debug
 		self._async = async
@@ -25,6 +28,10 @@ class Admin(object):
 		self._daemon_action_result = True
 		self._daemon_action_errstr = ""
 		self._controller = None
+		self._log_token = None
+		self._log_level = log_level
+		# 25 seconds default DBus timeout + 5 seconds safety margin
+		self._log_capture_timeout = self._timeout + 25 + 5
 		if self._dbus:
 			self._controller = tuned.admin.DBusController(consts.DBUS_BUS, consts.DBUS_INTERFACE, consts.DBUS_OBJECT, debug)
 			try:
@@ -72,6 +79,8 @@ class Admin(object):
 				return False
 		if self._dbus:
 			try:
+				self._controller.set_on_exit_action(
+						self._log_capture_finish)
 				self._controller.set_action(action_dbus, *args, **kwargs)
 				res = self._controller.run()
 			except TunedAdminDBusException as e:
@@ -218,6 +227,17 @@ class Admin(object):
 				return self._controller.exit(True)
 		return False
 
+	def _log_capture_finish(self):
+		if self._log_token is None or self._log_token == "":
+			return
+		try:
+			log_msgs = self._controller.log_capture_finish(
+					self._log_token)
+			self._log_token = None
+			self._error(log_msgs)
+		except TunedAdminDBusException as e:
+			self._error("Error: Failed to stop log capture. Restart the Tuned daemon to prevent a memory leak.")
+
 	def _action_dbus_profile(self, profiles):
 		if len(profiles) == 0:
 			return self._action_dbus_list()
@@ -225,6 +245,10 @@ class Admin(object):
 		if profile_name == "":
 			return self._controller.exit(False)
 		self._daemon_action_finished.clear()
+		if not self._async and self._log_level is not None:
+			self._log_token = self._controller.log_capture_start(
+					self._log_level,
+					self._log_capture_timeout)
 		(ret, msg) = self._controller.switch_profile(profile_name)
 		if self._async or not ret:
 			return self._controller.exit(self._profile_print_status(ret, msg))
@@ -266,6 +290,10 @@ class Admin(object):
 	def _action_dbus_auto_profile(self):
 		profile_name = self._controller.recommend_profile()
 		self._daemon_action_finished.clear()
+		if not self._async and self._log_level is not None:
+			self._log_token = self._controller.log_capture_start(
+					self._log_level,
+					self._log_capture_timeout)
 		(ret, msg) = self._controller.auto_profile()
 		if self._async or not ret:
 			return self._controller.exit(self._profile_print_status(ret, msg))

tuned/admin/dbus_controller.py

@@ -17,6 +17,7 @@ class DBusController(object):
 		self._debug = debug
 		self._main_loop = None
 		self._action = None
+		self._on_exit_action = None
 		self._ret = True
 		self._exit = False
 		self._exception = None
@@ -42,12 +43,20 @@ class DBusController(object):
 				self._exit = True
 
 		if self._exit:
+			if self._on_exit_action is not None:
+				self._on_exit_action(*self._on_exit_action_args,
+						**self._on_exit_action_kwargs)
 			self._main_loop.quit()
 			return False
 		else:
 			time.sleep(1)
 		return True
 
+	def set_on_exit_action(self, action, *args, **kwargs):
+		self._on_exit_action = action
+		self._on_exit_action_args = args
+		self._on_exit_action_kwargs = kwargs
+
 	def set_action(self, action, *args, **kwargs):
 		self._action = action
 		self._action_args = args
@@ -96,6 +105,12 @@ class DBusController(object):
 	def profile_info(self, profile_name):
 		return self._call("profile_info", profile_name)
 
+	def log_capture_start(self, log_level, timeout):
+		return self._call("log_capture_start", log_level, timeout)
+
+	def log_capture_finish(self, token):
+		return self._call("log_capture_finish", token)
+
 	def active_profile(self):
 		return self._call("active_profile")
 

tuned/consts.py

@@ -1,3 +1,5 @@
+import logging
+
 GLOBAL_CONFIG_FILE = "/etc/tuned/tuned-main.conf"
 ACTIVE_PROFILE_FILE = "/etc/tuned/active_profile"
 PROFILE_MODE_FILE = "/etc/tuned/profile_mode"
@@ -113,3 +115,12 @@ ACTIVE_PROFILE_MANUAL = "manual"
 
 LOG_LEVEL_CONSOLE = 60
 LOG_LEVEL_CONSOLE_NAME = "CONSOLE"
+CAPTURE_LOG_LEVEL = "error"
+CAPTURE_LOG_LEVELS = {
+		"debug": logging.DEBUG,
+		"info": logging.INFO,
+		"warn": logging.WARN,
+		"error": logging.ERROR,
+		"console": LOG_LEVEL_CONSOLE,
+		"none": None,
+		}