Plugin lxc: use functions for top-level activities

This clarifies the flow of control and allows to use
MUNIN_CAP_DIRTYCONFIG later.

plugins/lxc/lxc-multigraph

@@ -178,13 +178,7 @@ title_case() {
 }
 
 
-# --- BASIC DEFINES
-
-active_guests=$(get_active_guests "$exclude")
-
-# --- AUTOCONF
-
-if [ "$1" = "autoconf" ]; then
+do_autoconf() {
    if [ ! -r /proc/net/dev ]; then
       echo "no (/proc/net/dev cannot be read)"
    elif [ ! -e "$lxcpath" ]; then
@@ -192,12 +186,13 @@ if [ "$1" = "autoconf" ]; then
    else
       echo yes
    fi
-   exit 0
-fi
+}
 
-# --- CONFIG OUTPUT
 
-if [ "$1" = "config" ]; then
+do_config() {
+   local active_guests guest_name draw_style
+   active_guests=$(get_active_guests "$exclude")
+
    cat <<EOF
 multigraph lxc_cpu
 graph_title CPU Usage
@@ -335,11 +330,12 @@ $(clean_fieldname "mem_inactive__${guest_name}").label ${guest_name}: Inactive
 $(clean_fieldname "mem_inactive__${guest_name}").type GAUGE
 EOF
    done
+}
 
-   exit 0
-fi
 
-# --- DATA OUTPUT
+do_fetch() {
+   local active_guests cpu_usage device value_up value_down
+   active_guests=$(get_active_guests "$exclude")
 
    echo "multigraph lxc_cpu"
    for guest_name in $active_guests
@@ -396,3 +392,23 @@ $(clean_fieldname "mem_active__${guest_name}").value $(get_lxc_cgroup_info "$gue
    $(clean_fieldname "mem_inactive__${guest_name}").value $(get_lxc_cgroup_info "$guest_name" "memory.stat" | grep total_inactive_anon | awk '{print $2;}')
 EOF
    done
+}
+
+
+case "${1:-}" in
+   autoconf)
+      do_autoconf
+      exit 0
+      ;;
+   config)
+      do_config
+      exit 0
+      ;;
+   "")
+      do_fetch
+      exit 0
+      ;;
+   *)
+      echo >&2 "Invalid action requested (none of: autoconf / config / '')"
+      exit 1
+esac