From: andrew@bower.uk
Source: daemontools
Version: 1:0.76-15
Severity: wishlist
Tags: patch
X-Debbugs-Cc: runit@packages.debian.org
Dear Maintainer,
The daemontools-inspired family of supervision suites typically share the
ability to emulate some subset of the daemontools tools with compatible
behaviour.
For example, chpst from runit can emulate envdir, envuidgid, pgrphack, setlock,
setuidgid and softlimit.
Similarly, run scripts for daemons using these suites, if they don't take
advantage of features unique to those suites, may be compatible between them.
In practice, that compatibility is limited because of features included in
distributions, such as runit service directories in Debian typically using
/usr/lib/runit/invoke-run to perform some standard actions. However, third
party-provided service directories especially may well stick to the basics. The
debian package 'publicfile' is compatible with daemontools and runit
supervision.
Ideally someone writing a run script that only needed the behaviour of
'setlock' would simply call 'setlock', for example. However, that would
mean unnecessarily depending on the daemontools package when your
service might be running with runit that already has 'chpst' installed,
and so will be written to use 'chpst -l' instead.
We can fix this by installing all the common tools using the Debian
'alternatives' mechanism. This is very lightweight - symlink traversal is
extremely cheap in Linux.
I attach a patch for daemontools that does this. For simplicitly it groups
together all the tools that 'chpst' can emulate (headlined by the 'envdir'
tool), but theses could be split into a different alternative for each tool if
one wanted that granularity. An additional group just contains 'fghack', which
my 'xchpst' tool can also emulate.
I also attach example patches for the 'runit' and 'xchpst' packages to show how
this could work.
Here is some example output:
# sudo update-alternatives --config daemontools
There are 3 choices for the alternative daemontools (providing
/usr/bin/envdir).
Selection Path Priority Status
------------------------------------------------------------
0 /usr/bin/envdir.djb 50 auto mode
1 /usr/bin/chpst 30 manual mode
2 /usr/bin/envdir.djb 50 manual mode
* 3 /usr/bin/xchpst 40 manual mode
Press to keep the current choice[*], or type selection number: 1
update-alternatives: using /usr/bin/chpst to provide /usr/bin/envdir
(daemontools) in manual mode
The presence of alternatives will also help developers trying to compare
behaviours across different toolsets.
What do you think about this idea?
Andrew
-- System Information:
Debian Release: forky/sid
APT prefers unstable
APT policy: (500, 'unstable'), (500, 'stable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386
Kernel: Linux 6.18.9+deb14-amd64 (SMP w/24 CPU threads; PREEMPT)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8),
ANGUAGE=en_GB:en
Shell: /bin/sh linked to /usr/bin/dash
Init: sysvinit (via /sbin/init)
LSM: AppArmor: enabled
diff --git a/debian/daemontools-man/envdir.8 b/debian/daemontool
-man/envdir.djb.8
similarity index 100%
rename from debian/daemontools-man/envdir.8
rename to debian/daemontools-man/envdir.djb.8
diff --git a/debian/daemontools-man/envuidgid.8 b/debian/daemont
ols-man/envuidgid.djb.8
similarity index 100%
rename from debian/daemontools-man/envuidgid.8
rename to debian/daemontools-man/envuidgid.djb.8
diff --git a/debian/daemontools-man/fghack.8 b/debian/daemontool
-man/fghack.djb.8
similarity index 100%
rename from debian/daemontools-man/fghack.8
rename to debian/daemontools-man/fghack.djb.8
diff --git a/debian/daemontools-man/pgrphack.8 b/debian/daemonto
ls-man/pgrphack.djb.8
similarity index 100%
rename from debian/daemontools-man/pgrphack.8
rename to debian/daemontools-man/pgrphack.djb.8
diff --git a/debian/daemontools-man/setlock.8 b/debian/daemontoo
s-man/setlock.djb.8
similarity index 100%
rename from debian/daemontools-man/setlock.8
rename to debian/daemontools-man/setlock.djb.8
diff --git a/debian/daemontools-man/setuidgid.8 b/debian/daemont
ols-man/setuidgid.djb.8
similarity index 100%
rename from debian/daemontools-man/setuidgid.8
rename to debian/daemontools-man/setuidgid.djb.8
diff --git a/debian/daemontools-man/softlimit.8 b/debian/daemont
ols-man/softlimit.djb.8
similarity index 100%
rename from debian/daemontools-man/softlimit.8
rename to debian/daemontools-man/softlimit.djb.8
diff --git a/debian/daemontools.alternatives b/debian/daemontools.alternatives
new file mode 100644
index 0000000..9ea64ae
--- /dev/null
+++ b/debian/daemontools.alternatives
@@ -0,0 +1,23 @@
+Name: daemontools
+Link: /usr/bin/envdir
+Alternative: /usr/bin/envdir.djb
+Dependents:
+ /usr/bin/envuidgid envuidgid /usr/bin/envuidgid.djb
+ /usr/bin/pgrphack pgrphack /usr/bin/pgrphack.djb
+ /usr/bin/setlock setlock /usr/bin/setlock.djb
+ /usr/bin/setuidgid setuidgid /usr/bin/setuidgid.djb
+ /usr/bin/softlimit softlimit /usr/bin/softlimit.djb
+ /usr/share/man/man8/envdir.8.gz envdir.8.gz /usr/share/man/ma
8/envdir.djb.8.gz
+ /usr/share/man/man8/envuidgid.8.gz envuidgid.8.gz /usr/share/
an/man8/envuidgid.djb.8.gz
+ /usr/share/man/man8/pgrphack.8.gz pgrphack.8.gz /usr/share/ma
/man8/pgrphack.djb.8.gz
+ /usr/share/man/man8/setlock.8.gz setlock.8.gz /usr/share/man/
an8/setlock.djb.8.gz
+ /usr/share/man/man8/setuidgid.8.gz setuidgid.8.gz /usr/share/
an/man8/setuidgid.djb.8.gz
+ /usr/share/man/man8/softlimit.8.gz softlimit.8.gz /usr/share/
an/man8/softlimit.djb.8.gz
+Priority: 50
+
+Name: fghack
+Link: /usr/bin/fghack
+Alternative: /usr/bin/fghack.djb
+Dependents:
+ /usr/share/man/man8/fghack.8.gz fghack.8.gz /usr/share/man/ma
8/fghack.djb.8.gz
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