[PATCH v2 1/5] unbound-dhcp-leases-bridge: Improve logging

[PATCH v2 1/5] unbound-dhcp-leases-bridge: Improve logging

[Michael Tremer]

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This improves logging and enables logging to the console.

Suggested-by: Anthony Heading <ajrh(a)ajrh.net>
Signed-off-by: Michael Tremer <michael.tremer(a)ipfire.org>
---
 config/unbound/unbound-dhcp-leases-bridge | 26 ++++++++++++++++-------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/config/unbound/unbound-dhcp-leases-bridge b/config/unbound/unbound-dhcp-leases-bridge
index a2df5f101..ce0cb8614 100644
--- a/config/unbound/unbound-dhcp-leases-bridge
+++ b/config/unbound/unbound-dhcp-leases-bridge
@@ -30,27 +30,37 @@ import re
 import signal
 import stat
 import subprocess
+import sys
 import tempfile
 
 import inotify.adapters
 
 LOCAL_TTL = 60
 
-def setup_logging(loglevel=logging.INFO):
-	log = logging.getLogger("dhcp")
+log = logging.getLogger("dhcp")
+log.setLevel(logging.DEBUG)
+
+def setup_logging(daemon=True, loglevel=logging.INFO):
 	log.setLevel(loglevel)
 
+	# Log to syslog by default
 	handler = logging.handlers.SysLogHandler(address="/dev/log", facility="daemon")
-	handler.setLevel(loglevel)
+	log.addHandler(handler)
 
+	# Format everything
 	formatter = logging.Formatter("%(name)s[%(process)d]: %(message)s")
 	handler.setFormatter(formatter)
 
-	log.addHandler(handler)
+	handler.setLevel(loglevel)
 
-	return log
+	# If we are running in foreground, we should write everything to the console, too
+	if not daemon:
+		handler = logging.StreamHandler()
+		log.addHandler(handler)
 
-log = logging.getLogger("dhcp")
+		handler.setLevel(loglevel)
+
+	return log
 
 def ip_address_to_reverse_pointer(address):
 	parts = address.split(".")
@@ -579,12 +589,12 @@ if __name__ == "__main__":
 		elif args.verbose >= 2:
 			loglevel = logging.DEBUG
 
-	setup_logging(loglevel)
+	setup_logging(daemon=args.daemon, loglevel=loglevel)
 
 	bridge = UnboundDHCPLeasesBridge(args.dhcp_leases, args.fix_leases,
 		args.unbound_leases, args.hosts)
 
-	ctx = daemon.DaemonContext(detach_process=args.daemon)
+	ctx = daemon.DaemonContext(detach_process=args.daemon, stderr=sys.stderr)
 	ctx.signal_map = {
 		signal.SIGHUP  : bridge.update_dhcp_leases,
 		signal.SIGTERM : bridge.terminate,
-- 
2.30.2

[PATCH v2 2/5] unbound-dhcp-leases-bridge: Fix inotify handling

[Michael Tremer]

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This patch changes that the script will listen to changes to the
directory instead of the file which got complicated when files got
renamed.

It also processes all changes at the same time and tries finding out
what actions have to be performed in order to avoid unnecessary
iterations.

The script is also limited to process any changes only once every five
seconds to keep resource usage in check on busy systems.

Suggested-by: Anthony Heading <ajrh(a)ajrh.net>
Signed-off-by: Michael Tremer <michael.tremer(a)ipfire.org>
---
 config/unbound/unbound-dhcp-leases-bridge | 70 +++++++++++++++--------
 1 file changed, 47 insertions(+), 23 deletions(-)

diff --git a/config/unbound/unbound-dhcp-leases-bridge b/config/unbound/unbound-dhcp-leases-bridge
index ce0cb8614..c0e5977bf 100644
--- a/config/unbound/unbound-dhcp-leases-bridge
+++ b/config/unbound/unbound-dhcp-leases-bridge
@@ -32,6 +32,7 @@ import stat
 import subprocess
 import sys
 import tempfile
+import time
 
 import inotify.adapters
 
@@ -82,6 +83,12 @@ class UnboundDHCPLeasesBridge(object):
 		self.fix_leases_file = fix_leases_file
 		self.hosts_file = hosts_file
 
+		self.watches = {
+			self.leases_file     : inotify.constants.IN_MODIFY,
+			self.fix_leases_file : 0,
+			self.hosts_file      : 0,
+		}
+
 		self.unbound = UnboundConfigWriter(unbound_leases_file)
 		self.running = False
 
@@ -89,37 +96,54 @@ class UnboundDHCPLeasesBridge(object):
 		log.info("Unbound DHCP Leases Bridge started on %s" % self.leases_file)
 		self.running = True
 
-		# Initial setup
-		self.hosts = self.read_static_hosts()
-		self.update_dhcp_leases()
+		i = inotify.adapters.Inotify()
 
-		i = inotify.adapters.Inotify([
-			self.leases_file,
-			self.fix_leases_file,
-			self.hosts_file,
-		])
+		# Add watches for the directories of every relevant file
+		for f, mask in self.watches.items():
+			i.add_watch(
+				os.path.dirname(f),
+				mask | inotify.constants.IN_CLOSE_WRITE | inotify.constants.IN_MOVED_TO,
+			)
 
-		for event in i.event_gen():
-			# End if we are requested to terminate
-			if not self.running:
-				break
+		# Enabled so that we update hosts and leases on startup
+		update_hosts = update_leases = True
 
-			if event is None:
-				continue
+		while self.running:
+			log.debug("Wakeup of main loop")
+
+			# Process the entire inotify queue and identify what we need to do
+			for event in i.event_gen():
+				# Nothing to do
+				if event is None:
+					break
+
+				# Decode the event
+				header, type_names, path, filename = event
 
-			header, type_names, watch_path, filename = event
+				file = os.path.join(path, filename)
 
-			# Update leases after leases file has been modified
-			if "IN_MODIFY" in type_names:
-				# Reload hosts
-				if watch_path == self.hosts_file:
-					self.hosts = self.read_static_hosts()
+				log.debug("inotify event received for %s: %s", file, " ".join(type_names))
 
+				# Did the hosts file change?
+				if self.hosts_file == file:
+					update_hosts = True
+
+				# We will need to update the leases on any change
+				update_leases = True
+
+			# Update hosts (if needed)
+			if update_hosts:
+				self.hosts = self.read_static_hosts()
+
+			# Update leases (if needed)
+			if update_leases:
 				self.update_dhcp_leases()
 
-			# If the file is deleted, we re-add the watcher
-			if "IN_IGNORED" in type_names:
-				i.add_watch(watch_path)
+			# Reset
+			update_hosts = update_leases = False
+
+			# Wait a moment before we start the next iteration
+			time.sleep(5)
 
 		log.info("Unbound DHCP Leases Bridge terminated")
 
-- 
2.30.2

[PATCH v2 3/5] unbound-dhcp-leases-bridge: Read configuration only once

[Michael Tremer]

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This saves some resources when we re-read the same configuration file
too often.

Suggested-by: Anthony Heading <ajrh(a)ajrh.net>
Signed-off-by: Michael Tremer <michael.tremer(a)ipfire.org>
---
 config/unbound/unbound-dhcp-leases-bridge | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/config/unbound/unbound-dhcp-leases-bridge b/config/unbound/unbound-dhcp-leases-bridge
index c0e5977bf..b098d98b4 100644
--- a/config/unbound/unbound-dhcp-leases-bridge
+++ b/config/unbound/unbound-dhcp-leases-bridge
@@ -22,6 +22,7 @@
 import argparse
 import datetime
 import daemon
+import functools
 import ipaddress
 import logging
 import logging.handlers
@@ -444,6 +445,7 @@ class Lease(object):
 		return "localdomain"
 
 	@staticmethod
+	@functools.cache
 	def read_settings(filename):
 		settings = {}
 
-- 
2.30.2

[PATCH v2 4/5] unbound-dhcp-leases-bridge: Initialize logging after daemonization

[Michael Tremer]

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Signed-off-by: Michael Tremer <michael.tremer(a)ipfire.org>
---
 config/unbound/unbound-dhcp-leases-bridge | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/config/unbound/unbound-dhcp-leases-bridge b/config/unbound/unbound-dhcp-leases-bridge
index b098d98b4..50a0e516a 100644
--- a/config/unbound/unbound-dhcp-leases-bridge
+++ b/config/unbound/unbound-dhcp-leases-bridge
@@ -615,8 +615,6 @@ if __name__ == "__main__":
 		elif args.verbose >= 2:
 			loglevel = logging.DEBUG
 
-	setup_logging(daemon=args.daemon, loglevel=loglevel)
-
 	bridge = UnboundDHCPLeasesBridge(args.dhcp_leases, args.fix_leases,
 		args.unbound_leases, args.hosts)
 
@@ -627,4 +625,6 @@ if __name__ == "__main__":
 	}
 
 	with ctx:
+		setup_logging(daemon=args.daemon, loglevel=loglevel)
+
 		bridge.run()
-- 
2.30.2

[PATCH v2 5/5] unbound-dhcp-leases-bridge: Don't open stderr on daemonization

[Michael Tremer]

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Signed-off-by: Michael Tremer <michael.tremer(a)ipfire.org>
---
 config/unbound/unbound-dhcp-leases-bridge | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/config/unbound/unbound-dhcp-leases-bridge b/config/unbound/unbound-dhcp-leases-bridge
index 50a0e516a..1446c88df 100644
--- a/config/unbound/unbound-dhcp-leases-bridge
+++ b/config/unbound/unbound-dhcp-leases-bridge
@@ -618,13 +618,14 @@ if __name__ == "__main__":
 	bridge = UnboundDHCPLeasesBridge(args.dhcp_leases, args.fix_leases,
 		args.unbound_leases, args.hosts)
 
-	ctx = daemon.DaemonContext(detach_process=args.daemon, stderr=sys.stderr)
-	ctx.signal_map = {
-		signal.SIGHUP  : bridge.update_dhcp_leases,
-		signal.SIGTERM : bridge.terminate,
-	}
-
-	with ctx:
+	with daemon.DaemonContext(
+		detach_process=args.daemon,
+		stderr=None if args.daemon else sys.stderr,
+		signal_map = {
+			signal.SIGHUP  : bridge.update_dhcp_leases,
+			signal.SIGTERM : bridge.terminate,
+		},
+	) as daemon:
 		setup_logging(daemon=args.daemon, loglevel=loglevel)
 
 		bridge.run()
-- 
2.30.2