Configuration generalised so that all options can be set via

environment variables, in configuration files or on the command-line.
Changed format of config.default to use defconf rather than
assignment, and include documentation for usage message.  All
configuration variables now have an equivalent command-line option.
For example, $NBD_DEVICE can be set on the command-line using the
--nbd-device option.  Options specified on the command-line override
options set in any other way.  New configuration option $WITH_TSM_NODE
(defaults to 1).  Removed -n option - this is implicitly replaced by
--with-tsm-node=0.  The -c option can now be specified multiple times
and interspersed with setting individual options - order is important.
New option --dump displays the current configuration settings and then
exits.  It can be inserted anywhere on the command-line and takes
immediate effect, so it should be at the end of the command-line to
display all specified settings.  Configuration settings can also be
set in autocluster's environment, where they override the settings in
config.default (but not those specified on the command-line, including
via -c).  Error trapping moved to after usage processing, so an
invalid command-line option causes the desired usage message to
appear.

Signed-off-by: Martin Schwenke <martin@meltin.net>

1 files changed, 159 insertions, 1 deletions

diff --git a/functions b/functions
index 80f76c5..f37d3bc 100644
--- a/functions
+++ b/functions
@@ -1,4 +1,4 @@
-# common functions for autocluster
+# common functions for autocluster (-*- shell-script -*-)
 
 # create a MAC address based on a hash of the cluster name
 # plus the adapter and node number
@@ -198,3 +198,161 @@ check_command() {
     fi
 }
 
+# Set a variable if it isn't already set.  This allows environment
+# variables to override default config settings.
+defconf() {
+    local v="$1"
+    local e="$2"
+
+    [ "${!v+x}" ] || eval "$v=\"$e\""
+}
+
+# Print the list of config variables defined in config.default.
+get_config_options() {( # sub-shell for local declaration of defconf()
+	local options=
+	defconf() { options="$options $1" ; }
+	. "$installdir/config.default"
+	echo $options
+)}
+
+# Produce a list of long options, suitable for use with getopt, that
+# represent the config variables defined in config.default.
+getopt_config_options() {
+    local x=$(get_config_options | tr 'A-Z_' 'a-z-')
+    echo "${x// /:,}:"
+}
+
+# Unconditionally set the config variable associated with the given
+# long option.
+setconf_longopt() {
+    local longopt="$1"
+    local e="$2"
+
+    local v=$(echo "${longopt#--}" | tr 'a-z-' 'A-Z_')
+    # unset so defconf will set it
+    eval "unset $v"
+    defconf "$v" "$e"
+}
+
+# Dump all of the current config variables.
+dump_config() {
+    local o
+    for o in $(get_config_options) ; do
+	echo "${o}=\"${!o}\""
+    done
+    exit 0
+}
+
+# Print text assuming it starts after other text in $startcol and
+# needs to wrap before $fillcol.  Subsequent lines start at $startcol.
+# Long "words" will extend past $fillcol.
+fill_text() {
+    local startcol="$1"
+    local fillcol="$2"
+    local text="$3"
+
+    local width=$(($fillcol - $startcol))
+    [ $width -lt 0 ] && width=$((78 - $startcol))
+
+    local out=""
+
+    local padding=$(printf "\n%${startcol}s" " ")
+
+    while [ -n "$text" ] ; do
+	local orig="$text"
+
+	# If we already have output then arrange padding on the next line.
+	[ -n "$out" ] && out="${out}${padding}"
+
+	# Break the text at $width.
+	out="${out}${text:0:${width}}"
+	text="${text:${width}}"
+
+	# If we have left over text then the line break may be ugly,
+	# so let's check and try to break it on a space.
+	if [ -n "$text" ] ; then
+	    if [ "${text:0:1}" != " " -a "${text: -1:1}" != " " ] ; then
+		# We didn't break on a space.  Arrange for the
+		# beginning of the broken "word" to appear on the next
+		# line but not if it will make us loop infinitely.
+		if [ "${orig}" != "${out##* }${text}" ] ; then
+		    text="${out##* }${text}"
+		    out="${out% *}"
+		else
+		    # Hmmm, doing that would make us loop, so add the
+		    # rest of the word from the remainder of the text
+		    # to this line and let it extend past $fillcol.
+		    out="${out}${text%% *}"
+		    if [ "${text# *}" != "$text" ] ; then
+			# Remember the text after the next space for next time.
+			text="${text# *}"
+		    else
+			# No text after next space.
+			text=""
+		    fi
+		fi
+	    else
+		# We broke on a space.  If it will be at the beginning
+		# of the next line then remove it.
+		text="${text# }"
+	    fi
+	fi
+    done
+
+    echo "$out"
+}
+
+# Display usage text, trying these approaches in order.
+# 1. See if it all fits on one line before $fillcol.
+# 2. See if splitting before the default value and indenting it
+#    to $startcol means that nothing passes $fillcol.
+# 3. Treat the message and default value as a string and just us fill_text()
+#    to format it. 
+usage_display_text() {
+    local startcol="$1"
+    local fillcol="$2"
+    local desc="$3"
+    local default="$4"
+    
+    local width=$(($fillcol - $startcol))
+
+    # To avoid clutter, only quote values that need it.
+    #local q=
+    #[ -z "$default" -o "$(echo $default)" = "${default// /}" ] || q="\""
+    default="(default \"$default\")"
+
+    if [ $((${#desc} + 1 + ${#default})) -le $width ] ; then
+	echo "${desc} ${default}"
+    else
+	local padding=$(printf "%${startcol}s" " ")
+
+	if [ ${#desc} -lt $width -a ${#default} -lt $width ] ; then
+	    echo "$desc"
+	    echo "${padding}${default}"
+	else
+	    fill_text $startcol $fillcol "${desc} ${default}"
+	fi
+    fi
+}
+
+# Display usage information for long config options.
+usage_config_options(){( # sub-shell for local declaration of defconf()
+	local def_fillcol=78
+	local fillcol=$def_fillcol
+	local rows=$(stty size | sed -e 's@.* @@')
+	[ -n "$rows" ] && fillcol=$(($rows - 2))
+
+	local startcol=33
+
+	# We need to have at least one column... negative is also a problem.
+	[ $fillcol -le $startcol ] && fillcol=$def_fillcol
+
+	defconf() {
+	    local local longopt=$(echo "$1" | tr 'A-Z_' 'a-z-')
+
+	    printf "     --%-25s " "${longopt}=${3}" >&2
+
+	    usage_display_text $startcol $fillcol "$4" "$2" >&2
+	}
+	. "$installdir/config.default"
+)}