Creating 'install.conf' for OpenBSD autoinstall(8), another approach

[J65nko]

The other older 2014 approach is the shell script and Makefile from Creating 'install.conf' for OpenBSD automatic installations
Because I did not have to time to update that script for VPS testing, I wrote a Makefile that concatenates or glues together an install.conf from separate file blocks or components.

These blocks can have comment lines and empty lines to enhance readability. For a 'lean and mean' install.conf the Makefile just strips these lines.

An example of the quite readable network configuration block:

cat 10-network.resp
# network response file

# system hostname selects sitexx-$(hostname -s).tgz !
System hostname = df-us

# --- Network interface configuration

#Which network interface do you wish to configure = bge0
#IPv4 address for bge0 = autoconf
#IPv6 address for bge0 = none
#Which network interface do you wish to configure = done

Which network interface do you wish to configure = vio0
IPv4 address for vio0 = autoconf
IPv6 address for vio0 = none
Which network interface do you wish to configure = done

Start sshd(8) by default = yes
# -----------------------------------------

After being processed by make, it will be:

System hostname = df-us
Which network interface do you wish to configure = vio0
IPv4 address for vio0 = autoconf
IPv6 address for vio0 = none
Which network interface do you wish to configure = done
Start sshd(8) by default = yes

The list of response blocks are:

-rw-r--r--  1 j65  j65  572 Jul 19 02:05 10-network.resp
-rw-r--r--  1 j65  j65  512 Jul 19 02:01 20-user-tz.resp
-rw-r--r--  1 j65  j65  279 Jul 19 00:18 40-disk.resp
-rw-r--r--  1 j65  j65  450 Jul 19 00:21 50-sets.resp

The first relevant lines of the Makefile define a variable CONF for the file 'to make' and accumulates all separate reponse blocks in the variable BLOCKS :

CONF            = install.conf

[snip]

BLOCKS          += 10-network.resp
BLOCKS          += 20-user-tz.resp
BLOCKS          += 40-disk.resp
BLOCKS          += 50-sets.resp

The second target or sub-contractor install.conf.raw depends on the response blocks named in the variable BLOCKS

${CONF}.raw: ${BLOCKS}
        cat ${.ALLSRC} > ${.TARGET}

When any of these blocks have been modified and thus have a newer date, the shell commands of second line will get executed to create a newer updated version of install.conf.raw.

Updating or modifying the first block with a dangerous command (imagine what if I used only a single '>')

$ echo '# end of file' >>10-network.resp
$ ls -lTt 10-network.resp install.conf.raw
-rw-r--r--  1 j65  j65   586 Jul 19 02:51:07 2022 10-network.resp
-rw-r--r--  1 j65  j65  1813 Jul 19 02:13:40 2022 install.conf.raw

We see that this component is now newer that than the file it should be part of. Invoke make to recreate:

$ make install.conf.raw
cat 10-network.resp 20-user-tz.resp 40-disk.resp 50-sets.resp > install.conf.raw
$ make install.conf.raw
`install.conf.raw' is up to date.
ls -lTt *resp *raw
-rw-r--r--  1 j65  j65  1827 Jul 19 02:54:49 2022 install.conf.raw
-rw-r--r--  1 j65  j65   586 Jul 19 02:51:07 2022 10-network.resp
-rw-r--r--  1 j65  j65   512 Jul 19 02:01:18 2022 20-user-tz.resp
-rw-r--r--  1 j65  j65   450 Jul 19 00:21:13 2022 50-sets.resp
-rw-r--r--  1 j65  j65   279 Jul 19 00:18:56 2022 40-disk.resp

After the second invocation make, correctly informs us that there is no need to recreate: 'install.conf.raw' already contains the updated '10-network.resp' file.

The first and main target 'install.conf' depends on 'install.conf.raw'

${CONF}: ${CONF}.raw
        @# remove blank lines and #comment lines
        /usr/bin/sed -E -e '/^[:blank:]*$$/d' -e '/^#.*$$/d' ${.TARG
        @# note that in the shell a single '$' (end-of-line) works :
        @# make(1) strips one, so it needs to be doubled !!

Because of this dependency, it will first 'run' the 'install.conf.raw' target to make sure that is up to date.

$ make
/usr/bin/sed -E -e '/^[:blank:]*$/d' -e '/^#.*$/d' install.conf.raw >install.conf
$ make
`install.conf' is up to date.
$ make ls
ls -lTt
total 56
-rw-r--r--  1 j65  j65  1043 Jul 19 03:06:53 2022 install.conf
-rw-r--r--  1 j65  j65  1827 Jul 19 02:54:49 2022 install.conf.raw
-rw-r--r--  1 j65  j65   586 Jul 19 02:51:07 2022 10-network.resp
-rw-r--r--  1 j65  j65   512 Jul 19 02:01:18 2022 20-user-tz.resp
-rw-r--r--  1 j65  j65   450 Jul 19 00:21:13 2022 50-sets.resp
-rw-r--r--  1 j65  j65   279 Jul 19 00:18:56 2022 40-disk.resp

[J65nko]

The Makefile

# --- Makefile to generate an 'install.conf' for autoinstall(8) 
# Copyright (c) 2022 j65nko daemonforums.org
# ISC license (See https://cvsweb.openbsd.org/src/share/misc/license.template?rev=HEAD )

# --- ignore built-in rules
.MAKEFLAGS 	= -r

CONF		= install.conf

# For readability blocks can have comment lines and empty lines 
# These will be stripped from the final 'install.conf'
 
BLOCKS		+= 10-network.resp
BLOCKS		+= 20-user-tz.resp
BLOCKS		+= 40-disk.resp
BLOCKS		+= 50-sets.resp

# Main target strips the comment and empty lines from the 'raw' file

${CONF}: ${CONF}.raw
	@# remove blank lines and #comment lines 
	/usr/bin/sed -E -e '/^[:blank:]*$$/d' -e '/^#.*$$/d' ${.TARGET}.raw >${.TARGET} 
	@# note that in the shell a single '$' (end-of-line) works : '/^[:blank:]*$/d'
	@# make(1) strips one, so it needs to be doubled !!

# Concatenate all raw blocks to one single file

${CONF}.raw: ${BLOCKS} 
	cat ${.ALLSRC} > ${.TARGET}

# Utilities

ls:
	ls -lTt
  
show:
	ls -lT ${CONF}
	cat -n ${CONF}

showraw:
	ls -lT ${CONF}.raw
	cat -n ${CONF}.raw

clean:
	rm -f ${CONF} ${CONF}.raw	

.PHONY	: show clean

[J65nko]

The Makefile and response file in a single compressed tarball for downloading.
Create a directory e.g. AUTO-install, copy the tarball and extract

$ mkdir AUTO-install
$ cd AUTO-install
$ cp ~/Downloads/MakeInstallconf.tgz  .

# check the tarball contents

$ tar tvzf MakeInstallconf.tgz                   

-rw-r--r--  1 adriaan  adriaan        586 Jul 19 02:51 10-network.resp
-rw-r--r--  1 adriaan  adriaan        512 Jul 19 02:01 20-user-tz.resp
-rw-r--r--  1 adriaan  adriaan        279 Jul 19 04:10 40-disk.resp
-rw-r--r--  1 adriaan  adriaan        447 Jul 19 04:12 50-sets.resp
-rw-r--r--  1 adriaan  adriaan       1121 Jul 19 03:46 Makefile
-rw-r--r--  1 adriaan  adriaan       1040 Jul 19 04:12 install.conf
-rw-r--r--  1 adriaan  adriaan       1824 Jul 19 04:12 install.conf.raw

# extract

$ tar xvzf MakeInstallconf.tgz   
10-network.resp
20-user-tz.resp
40-disk.resp
50-sets.resp
Makefile
install.conf
install.conf.raw