[28277] in Source-Commits
cupsys-config commit: Add Upstart job; tweak initscripts
daemon@ATHENA.MIT.EDU (Jonathan D Reed)
Sun Jun 22 12:28:22 2014
Date: Sun, 22 Jun 2014 12:28:13 -0400
From: Jonathan D Reed <jdreed@MIT.EDU>
Message-Id: <201406221628.s5MGSDrl005769@drugstore.mit.edu>
To: source-commits@MIT.EDU
https://github.com/mit-athena/cupsys-config/commit/ce9505455e4d8399b63510592bd291315c95b7bd
commit ce9505455e4d8399b63510592bd291315c95b7bd
Author: Jonathan Reed <jdreed@mit.edu>
Date: Thu Jun 19 18:47:56 2014 -0400
Add Upstart job; tweak initscripts
Per (Trac: #1492), there is a weird race condition on Trusty, due
to the avahi-cups-reload Upstart job reloading CUPS, and clashing
with our restarting CUPS in configure-athena-printers.
- Ship an upstart job "configure-athena-printers", which starts when
CUPS is started, and tries up to 5 times to configure the printers.
We are deliberately NOT using dh_installinit here, since this Upstart
job can and should exist in parallel with the rc script, so we can
easily support non-Upstart distros without adding the compatibility
shims that dh_installinit wants.
- Tweak configure-athena-printers to take a second argument ("init"),
which indicates that the script was started from init, and thus it
should expect CUPS to be running, and not try to restart it.
- Tweak the initscript to be aware of the upstart job, and to not do
anything if it looks like Upstart will deal.
- Add a note for future generations in restart_cups.sh, should we
ever decide to use that again.
- Tell dh_installinit to start the initscript as late as possible
debian/changelog | 10 ++++++
debian/configure-athena-printers | 23 +++++++++++---
debian/configure-athena-printers.conf | 53 +++++++++++++++++++++++++++++++++
debian/control | 2 +-
debian/debathena-cupsys-config.init | 30 +++++++++++++++++--
debian/install | 1 +
debian/restart-cups.sh | 3 ++
debian/rules | 3 ++
8 files changed, 116 insertions(+), 9 deletions(-)
diff --git a/debian/changelog b/debian/changelog
index 96220ea..c3ca4fb 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,13 @@
+debathena-cupsys-config (1.19) unstable; urgency=low
+
+ * Ship an upstart job for Upstart-aware systems
+ * Make the sysv init script aware of the Upstart job, and defer to it
+ * Modify configure-athena-printers so it knows whether it's being called
+ from init or not; it will not attempt to start CUPS on its own if
+ called from init (Trac: #1492)
+
+ -- Jonathan Reed <jdreed@mit.edu> Fri, 20 Jun 2014 08:36:26 -0400
+
debathena-cupsys-config (1.18) unstable; urgency=low
* Remove all vestiges of BrowsePolling (Trac: #1473)
diff --git a/debian/configure-athena-printers b/debian/configure-athena-printers
index 6b18384..68ee7cb 100755
--- a/debian/configure-athena-printers
+++ b/debian/configure-athena-printers
@@ -120,10 +120,23 @@ require_cups() {
else
invoke="/etc/init.d/$rcname"
fi
+ # Even on Upstart-based systems, this can be used as
+ # a conditional, even though "status cups" cannot.
if ! /etc/init.d/$rcname status; then
- if ! $invoke start; then
- echo "FATAL: Couldn't start CUPS!"
- exit 1
+ if [ "$1" = "init" ]; then
+ # We were started from the init script. Init should
+ # also have started CUPS. Oh well...
+ if [ "$(lpstat -r)" != "scheduler is running" ]; then
+ echo "WARNING: CUPS not running; no printers added."
+ exit 2
+ fi
+ else
+ echo -n "Attempting to start cups..."
+ if ! $invoke start; then
+ echo "FATAL: Couldn't start CUPS!"
+ exit 1
+ fi
+ echo "started."
fi
fi
if [ "$(lpstat -r)" != "scheduler is running" ]; then
@@ -134,11 +147,11 @@ require_cups() {
case "$1" in
add)
- require_cups
+ require_cups "$2"
add_printers
;;
remove)
- require_cups
+ require_cups "$2"
del_printers
;;
*)
diff --git a/debian/configure-athena-printers.conf b/debian/configure-athena-printers.conf
new file mode 100644
index 0000000..d798156
--- /dev/null
+++ b/debian/configure-athena-printers.conf
@@ -0,0 +1,53 @@
+author "Massachusetts Institute of Technology <release-team@mit.edu>"
+description "Ensure MIT printers are configured"
+
+# This is an Upstart job to ensure Athena printers are configured.
+# It will be primarily used on Ubuntu, but could be used on any
+# Upstart system. Its primary purpose is to avoid dumb race conditions
+# between Upstart and traditional rc scripts.
+#
+# Before doing anything to this file, please go read
+# /etc/init.d/debathena-cupsys-config and make sure you understand it
+
+respawn
+# up to 5 times in 10 seconds
+respawn limit 5 10
+
+console log
+
+start on started cups
+task
+
+script
+ if [ ! -f /var/lib/debathena-cupsys-config-reconfigure_required ]; then
+ exit 0
+ fi
+ echo "configure-athena-printers: start at $(date)" >&2
+ echo "MIT Printer reconfiguration required." >&2
+ nologin=0
+ if [ ! -f /var/run/athena-nologin ]; then
+ # Block the greeter
+ touch /var/run/athena-nologin
+ nologin=1
+ fi
+ status=0
+ if /usr/lib/debathena-cupsys-config/configure-athena-printers add init; then
+ rm -f /var/lib/debathena-cupsys-config-reconfigure_required
+ echo "MIT printer configuration successful." >&2
+ else
+ status=$?
+ if [ "$status" = "2" ]; then
+ echo "Configuration failed because CUPS was not running; will respawn" >&2
+ else
+ echo "MIT printer configuration failed." >&2
+ fi
+ # Delay before Upstart respawns us
+ sleep 1
+ fi
+ # Only remove the nologin file if we created it
+ if [ $nologin -eq 1 ]; then
+ rm /var/run/athena-nologin
+ fi
+ echo "configure-athena-printers: end at $(date) with status $status" >&2
+ exit $status
+end script
diff --git a/debian/control b/debian/control
index 90bf08a..f145e22 100644
--- a/debian/control
+++ b/debian/control
@@ -2,7 +2,7 @@ Source: debathena-cupsys-config
Section: debathena-config/net
Priority: extra
Maintainer: Debathena Project <debathena@mit.edu>
-Build-Depends: debhelper (>= 7), config-package-dev (>= 5.0~)
+Build-Depends: debhelper (>= 7.0.50~), config-package-dev (>= 5.0~)
Standards-Version: 3.9.3
Package: debathena-cupsys-config
diff --git a/debian/debathena-cupsys-config.init b/debian/debathena-cupsys-config.init
index 7f91070..0411535 100755
--- a/debian/debathena-cupsys-config.init
+++ b/debian/debathena-cupsys-config.init
@@ -13,6 +13,25 @@
. /lib/lsb/init-functions
+using_upstart() {
+ local JOB_NAME=configure-athena-printers
+ # Do our best to determine if the upstart job is likely to run
+ # If the job doesn't exist, we're not using upstart
+ [ -f "/etc/init/${JOB_NAME}.conf" ] || return 1
+ # If there's no initctl, we're not using upstart
+ hash initctl 2>/dev/null || return 1
+ # If initctl doesn't know about the job, we're not using upstart
+ initctl status "$JOB_NAME" || return 1
+ # At this point, it is highly likely we're using Upstart. If we're not,
+ # something is horribly wrong.
+ return 0
+}
+
+if using_upstart; then
+ log_success_msg "debathena-cupsys-config: Skipping rc in favor of Upstart"
+ exit 0
+fi
+
case "$1" in
start)
if [ -f /var/lib/debathena-cupsys-config-reconfigure_required ]; then
@@ -22,11 +41,16 @@ case "$1" in
touch /var/run/athena-nologin
nologin=1
fi
- if /usr/lib/debathena-cupsys-config/configure-athena-printers add; then
+ if /usr/lib/debathena-cupsys-config/configure-athena-printers add init; then
rm -f /var/lib/debathena-cupsys-config-reconfigure_required
- log_end_msg 0
+ log_success_msg "Added MIT printers"
else
- log_end_msg 1
+ status=$?
+ if [ "$status" = "2" ]; then
+ log_warning_msg "CUPS not running, could not add MIT printers"
+ else
+ log_failure_msg "Failed to add MIT printers"
+ fi
fi
[ $nologin -eq 1 ] && rm /var/run/athena-nologin
fi
diff --git a/debian/install b/debian/install
index 9e2d404..0f95054 100644
--- a/debian/install
+++ b/debian/install
@@ -1,2 +1,3 @@
debian/restart-cups.sh usr/lib/debathena-cupsys-config
debian/configure-athena-printers usr/lib/debathena-cupsys-config
+debian/configure-athena-printers.conf etc/init
diff --git a/debian/restart-cups.sh b/debian/restart-cups.sh
index 4f9a8bd..ff76274 100644
--- a/debian/restart-cups.sh
+++ b/debian/restart-cups.sh
@@ -5,6 +5,9 @@ restart_cups()
# hilarity, we'll keep this hook around, but only restart
# CUPS if it's running, and don't error out if we can't.
+ # Note that this will likely end badly on Trusty+, due to the
+ # avahi-cups-reload Upstart job. Test it before making changes.
+
# It's not 2008 anymore, there's nothing named "cupsys"
rcname=cups
if /etc/init.d/$rcname status; then
diff --git a/debian/rules b/debian/rules
index a089a9e..e750e84 100755
--- a/debian/rules
+++ b/debian/rules
@@ -2,3 +2,6 @@
%:
dh $@ --with config-package
+
+override_dh_installinit:
+ dh_installinit --no-start --update-rcd-params="defaults 90 10"
