Bug#727708: tech-ctte: Decide which init system to default to in Debian.

[Peter Dolding <oiaohm@gmail.com>]

Russ Allbery (rra@debian.org)

> In general, upstart's integration with arbitrary actions in shell
> fragments is considerably better than systemd's, at least based on the
> documentation I've read.  upstart feels like it provides more useful
> flexibility

This is in fact a extremely bad idea how it is implemented in upstart.

ExecStartPre=, ExecStartPost=,ExecReload=.... Kind of model in systemd
is better.

1 the upstart method you have to be watching the version of shell that
the scripts in the init system are using.   So we are back to the
sysvinit problem of update bash and hello stack of stuff don't start
any more.  ExecStartPre=/bin/bash somescript.sh

Think lets say I am a php or python developer.   Upstream.  Why do
they have to code there init items in bash or some other shell script.

The one property about systemd unit files that is extremely good is
there are no multi line commands.   Every command is a single line.

script
    # do some stuff
    if [ ... ]; then
        ...
    fi
end script

This pattern in upstart is in fact highly bad.

script
    # do some stuff
    if [ ... ]; then
        ...
    fi
end script

post-stop script
    # do some stuff
    if [ ... ]; then
        ...
    fi
end script

Think about this case.   While editing you by mistake delete something.

script
    # do some stuff
    if [ ... ]; then
        ...
    fi

post-stop script
    # do some stuff
    if [ ... ]; then
        ...
    fi
end script

See what missing.   Now your service start does something completely you wrong.

--script instead gives shell script code that will be executed using /bin/sh.--

Exactly what says that /bin/sh will be bash ash dash.....   Basically
you need to be able to declare interpreter of script.  Under sysvinit
you can declare interpreter of script.   systemd and openrc you can
also declare interpreter of script.   upstart has it hard coded.
This hard coded bit is bad.

systemd forces you to use many small shell files.  With systemd you
delete a line you take out a complete command.   You cannot mutate the
command todo something strange.

We are in a modern age of Languages there is no point taking in a init
system that forces the usage of one scripting interpreter that can
change and bring the system down.


Peter Dolding