Re: Adding a 'setup' phase to service startup?

[Dean Hall <deanpence@gmail.com>]

Lars Kellogg-Stedman wrote:
>>Although I think runit itself should remain pristine in that it only
>>runs the ./run script for a service...

I almost forgot. Here's a sample implementation that I'm currently using
for dnscache. This is only one method of using sv-tools, but I think
it's an elegant one. Also, I think it's one that leaves the most room
open for elegant automation and even (for those who like them) GUI tools.

(Please keep in mind that I'm running on gentoo, which is very
FHS-compliant; some day I'll break out of the FHS shell (again).)


# This envdir sets the environment for sv-run. It tells sv-run not to
check dependencies and gives it an envdir to fetch before calling
./run-service.
--------
`envdir-print /etc/envdir.d/dnscache/meta`:
--------
SV_NO_DEPS='1'
SV_RUN_ENVDIR='/etc/envdir.d/dnscache/prerun'
--------

# This envdir sets the environment for ./run-service.
--------
`envdir-print /etc/envdir.d/dnscache/prerun`:
--------
ENVDIR='/etc/envdir.d/dnscache/service'
SEED='/var/lib/dnscache-seed'
USER='dnscache'
--------

# This envdir sets the environment for dnscache itself.
--------
`envdir-print /etc/envdir.d/dnscache/service`:
--------
CACHESIZE='10000000'
DATALIMIT='30000000'
IP='192.168.0.53'
IPSEND='0.0.0.0'
ROOT='/etc/service.d/all/dnscache/root'
--------

# Obviously, this gets run first:
--------
./run:
--------
#!/bin/sh
#
PATH='/usr/sbin:/usr/bin:/sbin:/bin'

exec 2>&1
exec \
        envdir /etc/envdir.d/dnscache/meta \
        sv-run
--------

# After checking dependencies and such, sv-run runs this:
--------
./run-service:
--------
#!/bin/sh
#
# Requires:
# - USER
# - SEED
#
PATH='/usr/sbin:/usr/bin:/sbin:/bin'

# Create a new random seed.
dd if=/dev/urandom of="$SEED" count=1 bs=128 > /dev/null 2>&1

exec 2>&1
exec < "$SEED"
exec \
        env - PATH="$PATH" \
        envuidgid "$USER" \
        envdir "$ENVDIR" \
        dnscache
--------


d