From 625df8486407fd2821b4eea91361805a2c4ea647 Mon Sep 17 00:00:00 2001
From: Marcio Barbosa <mbarbosa@sinenomine.net>
Date: Wed, 1 May 2019 00:44:45 -0300
Subject: [PATCH] afs-client-accessd: allow configuration of export time

Currently, every single host running afs-client-accessd exports the
collected data at midnight. Depending on how many hosts we have,
exporting several databases in parallel can overload the central host
and, as a result of that, substantially increase the time needed to
complete this operation.

To mitigate this problem, introduce a new configuration directive that
can be used to change the hour in which the databases should be
exported. With this directive, the number of nodes transferring data to
the central host at the same time can be reduced by setting different
export times for different hosts.
---
 admin/afs-client-accessd/afs-client-accessd   | 52 +++++++++++++++++--
 .../afs-client-accessd.conf.example           |  6 +++
 2 files changed, 54 insertions(+), 4 deletions(-)

diff --git a/admin/afs-client-accessd/afs-client-accessd b/admin/afs-client-accessd/afs-client-accessd
index 48315fc..895a55e 100755
--- a/admin/afs-client-accessd/afs-client-accessd
+++ b/admin/afs-client-accessd/afs-client-accessd
@@ -156,6 +156,15 @@ Example:
 
   AUDIT_PATH => '/usr/afs/logs/FileAudit',
 
+=item EXPORT_TIME
+
+This specifies the hour of the day (UTC) in which the *.sqlite files should be
+exported to the central host. The default is 0 (midnight).
+
+Example:
+
+  EXPORT_TIME => 16,
+
 =item SQLITE_PREFIX
 
 This specifies the directory in which the local disk databases will be stored
@@ -581,6 +590,7 @@ read_config()
 
 		MSGRCV_WORKAROUND => 0,
 		USE_FQDN => 0,
+		EXPORT_TIME => 0,
 	);
 
 	if (!-r $CONFIG_FILE) {
@@ -601,6 +611,11 @@ read_config()
 		$newcfg{$_} = $override{$_};
 	}
 
+	if ($newcfg{EXPORT_TIME} < 0 || $newcfg{EXPORT_TIME} > 24) {
+		$newcfg{EXPORT_TIME} = 0;
+	}
+	$newcfg{EXPORT_TIME} = $newcfg{EXPORT_TIME} * 60 * 60;
+
 	my $err = '';
 	if (! -d $newcfg{SQLITE_PREFIX}) {
 		$err .= "SQLITE_PREFIX dir $newcfg{SQLITE_PREFIX} does not exist\n";
@@ -1230,6 +1245,27 @@ spawn_exporter()
 	exit(0);
 }
 
+sub
+time_to_export()
+{
+	my $current_time = time();
+
+	my $sec_per_day = 24 * 60 * 60;
+	my $midnight = $current_time - ($current_time % $sec_per_day);
+
+	my $exp_time = $midnight + $CFG{EXPORT_TIME};
+
+	my $fluctuation = 90;
+	my $range = (ALARM_INTERVAL / 2) + $fluctuation;
+
+	if (($current_time > ($exp_time - $range)) &&
+	    ($current_time <= ($exp_time + $range))) {
+		return 1;
+	} else {
+		return 0;
+	}
+}
+
 my $checksignals_firstrun = 1;
 # check for changes flagged by a signal handler
 sub
@@ -1295,10 +1331,6 @@ checksignals()
 
 		stop_collection($next_dbname);
 
-		# export database in the background
-		d("Spawning exporter due to db name change");
-		spawn_exporter();
-
 		$CUR_DBNAME = $next_dbname;
 
 		# set up our sqlite stuff again so we can record new data to it
@@ -1322,6 +1354,18 @@ checksignals()
 		spawn_exporter();
 	}
 
+	my $sig_alarm = 0;
+
+	if (!$SIGNAL_SHUTDOWN && !$SIGNAL_CHILD && !$SIGNAL_CONFIG) {
+		$sig_alarm = 1;
+	}
+
+	if (!$EXPORTER_PID && $sig_alarm && time_to_export()) {
+		# export database in the background
+		d("Spawning exporter due to time_to_export");
+		spawn_exporter();
+	}
+
 	$checksignals_firstrun = 0;
 
 	$SIGNAL_SHUTDOWN = 0;
diff --git a/admin/afs-client-accessd/afs-client-accessd.conf.example b/admin/afs-client-accessd/afs-client-accessd.conf.example
index da17178..df1b39b 100644
--- a/admin/afs-client-accessd/afs-client-accessd.conf.example
+++ b/admin/afs-client-accessd/afs-client-accessd.conf.example
@@ -35,6 +35,12 @@ AUDIT_PATH => '/usr/afs/logs/FileAudit',
 
 SQLITE_PREFIX => '/var/afs-accessdb',
 
+# EXPORT_TIME specifies the hour of the day in which the databases from
+# SQLITE_PREFIX should be exported to the central host. The timezone is UTC and
+# the default value is 0 (midnight).
+
+EXPORT_TIME => 16,
+
 # RHEL 5.x broken msgrcv workaround. msgrcv fails supriously
 # on older versions of RHEL 5.x without setting the errno. strace
 # shows ERESTARTNOHAND errors.