[lvm-devel] master - lvmdbusd: Use udev until ExternalEvent occurs
tasleson
tasleson at fedoraproject.org
Mon Aug 29 20:28:38 UTC 2016
Gitweb: http://git.fedorahosted.org/git/?p=lvm2.git;a=commitdiff;h=4902034c895d26423564175c0636cff8ba4112e1
Commit: 4902034c895d26423564175c0636cff8ba4112e1
Parent: 2352ff24a55757a70869f443126d67cece0fb0a4
Author: Tony Asleson <tasleson at redhat.com>
AuthorDate: Wed Aug 24 18:29:35 2016 -0500
Committer: Tony Asleson <tasleson at redhat.com>
CommitterDate: Mon Aug 29 15:26:55 2016 -0500
lvmdbusd: Use udev until ExternalEvent occurs
The normal mode of operation will be to monitor for udev events until an
ExternalEvent occurs. In that case the service will disable monitoring
for udev events and use ExternalEvent exclusively.
Note: User specifies --udev the service will always monitor udev regardless
if ExternalEvent is being called too.
---
daemons/lvmdbusd/cfg.py | 14 +++++++++-----
daemons/lvmdbusd/cmdhandler.py | 24 ++++++++++++++++++------
daemons/lvmdbusd/lvm_shell_proxy.py | 6 ++++++
daemons/lvmdbusd/main.py | 28 ++++++++++++++--------------
daemons/lvmdbusd/manager.py | 9 ++++++++-
daemons/lvmdbusd/udevwatch.py | 25 ++++++++++++++++---------
daemons/lvmdbusd/utils.py | 2 +-
7 files changed, 72 insertions(+), 36 deletions(-)
diff --git a/daemons/lvmdbusd/cfg.py b/daemons/lvmdbusd/cfg.py
index 8aec8ae..1d773c3 100644
--- a/daemons/lvmdbusd/cfg.py
+++ b/daemons/lvmdbusd/cfg.py
@@ -24,14 +24,18 @@ om = None
# This is the global bus connection
bus = None
+# Command line args
+args = None
+
+# Set to true if we are depending on external events for updates
+ee = False
+
# Shared state variable across all processes
run = multiprocessing.Value('i', 1)
-# Debug
-DEBUG = True
-
-# Use lvm shell
-USE_SHELL = False
+# If this is set to true, the current setup support lvm shell and we are
+# running in that mode of operation
+SHELL_IN_USE = None
# Lock used by pprint
stdout_lock = multiprocessing.Lock()
diff --git a/daemons/lvmdbusd/cmdhandler.py b/daemons/lvmdbusd/cmdhandler.py
index 0d35782..5815031 100644
--- a/daemons/lvmdbusd/cmdhandler.py
+++ b/daemons/lvmdbusd/cmdhandler.py
@@ -13,6 +13,7 @@ import threading
from itertools import chain
import collections
import traceback
+import os
try:
from . import cfg
@@ -101,7 +102,8 @@ def call_lvm(command, debug=False):
# in different locations on the same box
command.insert(0, cfg.LVM_CMD)
- process = Popen(command, stdout=PIPE, stderr=PIPE, close_fds=True)
+ process = Popen(command, stdout=PIPE, stderr=PIPE, close_fds=True,
+ env=os.environ)
out = process.communicate()
stdout_text = bytes(out[0]).decode("utf-8")
@@ -111,7 +113,7 @@ def call_lvm(command, debug=False):
_debug_c(command, process.returncode, (stdout_text, stderr_text))
if process.returncode == 0:
- if cfg.DEBUG and out[1] and len(out[1]) and 'help' not in command:
+ if cfg.args.debug and out[1] and len(out[1]) and 'help' not in command:
log_error('WARNING: lvm is out-putting text to STDERR on success!')
_debug_c(command, process.returncode, (stdout_text, stderr_text))
@@ -123,9 +125,10 @@ def _shell_cfg():
try:
lvm_shell = LVMShellProxy()
_t_call = lvm_shell.call_lvm
- cfg.USE_SHELL = True
+ cfg.SHELL_IN_USE = lvm_shell
except Exception:
_t_call = call_lvm
+ cfg.SHELL_IN_USE = None
log_error(traceback.format_exc())
log_error("Unable to utilize lvm shell, dropping back to fork & exec")
@@ -133,6 +136,15 @@ def _shell_cfg():
def set_execution(shell):
global _t_call
with cmd_lock:
+ # If the user requested lvm shell and we are currently setup that
+ # way, just return
+ if cfg.SHELL_IN_USE and shell:
+ return
+ else:
+ if not shell and cfg.SHELL_IN_USE:
+ cfg.SHELL_IN_USE.exit_shell()
+ cfg.SHELL_IN_USE = None
+
_t_call = call_lvm
if shell:
_shell_cfg()
@@ -217,7 +229,7 @@ def pv_remove(device, remove_options):
def _qt(tag_name):
# When running in lvm shell you need to quote the tags
- if cfg.USE_SHELL:
+ if cfg.SHELL_IN_USE:
return '"%s"' % tag_name
return tag_name
@@ -440,7 +452,7 @@ def supports_json():
cmd = ['help']
rc, out, err = call(cmd)
if rc == 0:
- if cfg.USE_SHELL:
+ if cfg.SHELL_IN_USE:
return True
else:
if 'fullreport' in err:
@@ -488,7 +500,7 @@ def lvm_full_report_json():
# With the current implementation, if we are using the shell then we
# are using JSON and JSON is returned back to us as it was parsed to
# figure out if we completed OK or not
- if cfg.USE_SHELL:
+ if cfg.SHELL_IN_USE:
assert(type(out) == dict)
return out
else:
diff --git a/daemons/lvmdbusd/lvm_shell_proxy.py b/daemons/lvmdbusd/lvm_shell_proxy.py
index d4eff86..3455342 100755
--- a/daemons/lvmdbusd/lvm_shell_proxy.py
+++ b/daemons/lvmdbusd/lvm_shell_proxy.py
@@ -203,6 +203,12 @@ class LVMShellProxy(object):
return rc, json_result, error_msg
+ def exit_shell(self):
+ try:
+ self._write_cmd('exit\n')
+ except Exception as e:
+ log_error(str(e))
+
def __del__(self):
try:
self.lvm_shell.terminate()
diff --git a/daemons/lvmdbusd/main.py b/daemons/lvmdbusd/main.py
index 638323a..d76b5c3 100644
--- a/daemons/lvmdbusd/main.py
+++ b/daemons/lvmdbusd/main.py
@@ -92,6 +92,7 @@ def process_request():
def main():
+ start = time.time()
# Add simple command line handling
parser = argparse.ArgumentParser()
parser.add_argument("--udev", action='store_true',
@@ -112,16 +113,13 @@ def main():
# Ensure that we get consistent output for parsing stdout/stderr
os.environ["LC_ALL"] = "C"
- args = parser.parse_args()
+ cfg.args = parser.parse_args()
- cfg.DEBUG = args.debug
- cmdhandler.set_execution(args.use_lvm_shell)
+ cmdhandler.set_execution(cfg.args.use_lvm_shell)
# List of threads that we start up
thread_list = []
- start = time.time()
-
# Install signal handlers
for s in [signal.SIGHUP, signal.SIGINT]:
try:
@@ -144,7 +142,7 @@ def main():
cfg.load = load
- cfg.db = lvmdb.DataStore(args.use_json)
+ cfg.db = lvmdb.DataStore(cfg.args.use_json)
# Start up thread to monitor pv moves
thread_list.append(
@@ -160,23 +158,25 @@ def main():
process.damon = True
process.start()
+ # Add udev watching
+ if cfg.args.use_udev:
+ log_debug('Utilizing udev to trigger updates')
+
+ # In all cases we are going to monitor for udev until we get an
+ # ExternalEvent. In the case where we get an external event and the user
+ # didn't specify --udev we will stop monitoring udev
+ udevwatch.add()
+
end = time.time()
log_debug(
'Service ready! total time= %.4f, lvm time= %.4f count= %d' %
(end - start, cmdhandler.total_time, cmdhandler.total_count),
'bg_black', 'fg_light_green')
- # Add udev watching
- if args.use_udev:
- log_debug('Utilizing udev to trigger updates')
- udevwatch.add()
-
try:
if cfg.run.value != 0:
cfg.loop.run()
-
- if args.use_udev:
- udevwatch.remove()
+ udevwatch.remove()
for process in thread_list:
process.join()
diff --git a/daemons/lvmdbusd/manager.py b/daemons/lvmdbusd/manager.py
index 2388d8a..79254fe 100644
--- a/daemons/lvmdbusd/manager.py
+++ b/daemons/lvmdbusd/manager.py
@@ -17,7 +17,7 @@ from . import cmdhandler
from .fetch import load_pvs, load_vgs
from .request import RequestEntry
from .refresh import event_add
-
+from . import udevwatch
# noinspection PyPep8Naming
class Manager(AutomatedProperties):
@@ -181,6 +181,13 @@ class Manager(AutomatedProperties):
in_signature='s', out_signature='i')
def ExternalEvent(self, command):
+ # If a user didn't explicitly specify udev, we will turn it off now.
+ if not cfg.args.use_udev:
+ if udevwatch.remove():
+ utils.log_debug("ExternalEvent received, disabling "
+ "udev monitoring")
+ # We are dependent on external events now to stay current!
+ cfg.ee = True
event_add((command,))
return dbus.Int32(0)
diff --git a/daemons/lvmdbusd/udevwatch.py b/daemons/lvmdbusd/udevwatch.py
index c3e6e60..6d56443 100644
--- a/daemons/lvmdbusd/udevwatch.py
+++ b/daemons/lvmdbusd/udevwatch.py
@@ -8,10 +8,12 @@
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import pyudev
+import threading
from .refresh import event_add
from . import cfg
observer = None
+observer_lock = threading.RLock()
# noinspection PyUnusedLocal
@@ -40,15 +42,20 @@ def filter_event(action, device):
def add():
- global observer
- context = pyudev.Context()
- monitor = pyudev.Monitor.from_netlink(context)
- monitor.filter_by('block')
- observer = pyudev.MonitorObserver(monitor, filter_event)
- observer.start()
+ with observer_lock:
+ global observer
+ context = pyudev.Context()
+ monitor = pyudev.Monitor.from_netlink(context)
+ monitor.filter_by('block')
+ observer = pyudev.MonitorObserver(monitor, filter_event)
+ observer.start()
def remove():
- global observer
- observer.stop()
- observer = None
+ with observer_lock:
+ global observer
+ if observer:
+ observer.stop()
+ observer = None
+ return True
+ return False
diff --git a/daemons/lvmdbusd/utils.py b/daemons/lvmdbusd/utils.py
index 9db7857..65668fc 100644
--- a/daemons/lvmdbusd/utils.py
+++ b/daemons/lvmdbusd/utils.py
@@ -265,7 +265,7 @@ def _common_log(msg, *attributes):
# @param msg Message to output to stdout
# @return None
def log_debug(msg, *attributes):
- if cfg.DEBUG:
+ if cfg.args.debug:
_common_log(msg, *attributes)
More information about the lvm-devel
mailing list