Bug#66912: PROPOSAL] init script configuration variables
I (very belatedly) second this proposal. There's one small change I
would make though; see below.
On Sat, Jul 08, 2000 at 03:03:10AM -0700, Joey Hess wrote:
> Package: debian-policy
> Severity: wishlist
>
> There has been some discussion lately on debian-deval (and a bit on
> -policy) about init scripts. One concern that has arisen is that it can
> be very annoying to have to modify an init script to change a simple
> value in it, and then be forced to maintain your modified init script
> each time you upgrade and the package changes it. /etc/default is
> already in use by 3 packages (2 of them in base; also, see also bug
> #66574 point #3), this just formalizes it.
>
> The thread also brought up the concern that an init script might start
> using some new parameter, while the admin has modified its /etc/default/
> file, and so the parameter does not have a value set, and this causes
> the script to do something unexpected and/or bad. This proposal addresses
> that concern as well.
>
> It's late and my wording might be buggy -- patches gladly accpeted. I'm
> also looking for seconds, of course.
>
> (I believe this is a simple proposal that is orthagonal to some other
> things being thrown around in the init.d thread, so I hope discussion of
> this proposal can be limited to this alone and not drag the rest of that
> in.)
>
> --- policy.text.orig Sat Jul 8 02:21:49 2000
> +++ policy.text Sat Jul 8 02:44:34 2000
> @@ -1034,20 +1034,37 @@
> remain but the package has been removed, as configuration files remain
> on the system after the package has been removed. Only when `dpkg' is
> executed with the `--purge' option will configuration files be
> removed. In particular, the init script itself is usually a
> configuration file (see Section 3.3.5, `Notes'), and will remain on
> the system if the package is removed but not purged. Therefore, you
> should include a `test' statement at the top of the script, like this:
>
> test -f <program-executed-later-in-script> || exit 0
>
> + Often there are some values in the `init.d' scripts that a system
> + administrator will frequently want to change. While the scripts are
> + frequently conffiles, modifying them requires that the administrator
> + merge in their changes each time the package is upgraded and the
> + conffile changes. To ease the burden on the system administrator,
> + such configurable values should not be placed directly in the script.
> + Instead, they should be placed in a file in `/etc/default', which
> + typically will have the same base name as the `init.d' script. This
> + extra file can be sourced by the script when the script runs. It
> + must contain only variable settings and comments.
> +
> + To ensure that vital configurable values are always available, the
> + `init.d' script should set default values for each of the shell
> + variables it uses before sourcing the /etc/default/ file. Also, since
> + the `/etc/default/' file is often a conffile, the `init.d' script must
> + behave sensibly without failing if it is deleted.
> +
> 3.3.3. Managing the links
> -------------------------
>
> A program is provided, `update-rc.d', to handle the it easier for
> package maintainers to arrange for the proper creation and removal of
> `/etc/rc<n>.d' symbolic links, or their functional equivalent if
> another method is being used. This may be used by maintainers in
> their packages' `postinst' and `postrm' scripts.
>
> You should use this script to make changes to `/etc/rc<n>.d' and
> @@ -1113,61 +1130,76 @@
>
> 3.3.6. Example
> --------------
>
> The `bind' DNS (nameserver) package wants to make sure that the
> nameserver is running in multiuser runlevels, and is properly shut
> down with the system. It puts a script in `/etc/init.d', naming the
> script appropriately `bind'. As you can see, the script interprets
> the argument `reload' to send the nameserver a `HUP' signal (causing
> it to reload its configuration); this way the user can say
> - `/etc/init.d/bind reload' to reload the name server.
> + `/etc/init.d/bind reload' to reload the name server. The script has
> + one configurable value, which can be used to pass parameters to
> + the named program at startup.
>
> #!/bin/sh
> #
> # Original version by Robert Leslie
> # <rob@mars.org>, edited by iwj and cs
>
> test -x /usr/sbin/named || exit 0
>
> + # Source defaults file.
> + PARAMS=''
> + if [ -e /etc/default/bind ]; then
I would change the test to [ -f /etc/default/bind ].
> + . /etc/default/bind
> + fi
> +
> case "$1" in
> start)
> echo -n "Starting domain name service: named"
> - start-stop-daemon --start --quiet --exec /usr/sbin/named
> + start-stop-daemon --start --quiet --exec /usr/sbin/named -- $PARAMS
> echo "."
> ;;
> stop)
> echo -n "Stopping domain name service: named"
> start-stop-daemon --stop --quiet \
> --pidfile /var/run/named.pid --exec /usr/sbin/named
> echo "."
> ;;
> restart)
> echo -n "Restarting domain name service: named"
> start-stop-daemon --stop --quiet \
> --pidfile /var/run/named.pid --exec /usr/sbin/named
> - start-stop-daemon --start --verbose --exec /usr/sbin/named
> + start-stop-daemon --start --verbose --exec /usr/sbin/named -- $PARAMS
> echo "."
> ;;
> force-reload|reload)
> echo -n "Reloading configuration of domain name service: named"
> start-stop-daemon --stop --signal 1 --quiet \
> --pidfile /var/run/named.pid --exec /usr/sbin/named
> echo "."
> ;;
> *)
> echo "Usage: /etc/init.d/bind {start|stop|restart|reload|force-reload}" >&2
> exit 1
> ;;
> esac
>
> exit 0
> +
> + Complementing the above init script is a file '/etc/default/bind',
> + which contains configurable parameters used by the script.
> +
> + # Specified parameters to pass to named. See named(8).
> + # You may uncomment the following line, and edit to taste.
> + #PARAMS="-u nobody"
>
> Another example on which to base your `/etc/init.d' scripts is in
> `/etc/init.d/skeleton'.
Julian
--
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Julian Gilbey, Dept of Maths, QMW, Univ. of London. J.D.Gilbey@qmw.ac.uk
Debian GNU/Linux Developer, see http://www.debian.org/~jdg
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