control-vm.sh: Refactor logic and provide a help output

control-vm.sh

@@ -8,7 +8,7 @@
 # https://git.holgersson.xyz/nfr/control-vm
 # If that link does not work, feel free to drop me an email.
 
-# Version: 2024-05-23
+# For version see variable below comment section.
 # Author:  Nils Freydank <nils.freydank@datenschutz-ist-voll-doof.de>
 # License: MIT
 
@@ -65,9 +65,9 @@
 # CLIPBOARD="True"
 # _EOF
 
-# Provide a sanity check first.
-[[ -z "${1}" ]] && echo "Please provide a guest name!" && exit 1
+__VERSION__="0.0.0"
 
+set_params(){
   # === Define default values ===
   CLIPBOARD="${CLIPBOARD:-}"
   CPU_CORES="${CPU_CORES:-8}"
@@ -99,8 +99,8 @@ SPICE_SOCKET="${SPICE_SOCKET:-${BASE_PATH}/spice.socket}"
   if [[ -f "${GUEST_CONFIG_FILE}" ]]; then
       source "${GUEST_CONFIG_FILE}"
   else
-    echo "No configuration found. Aborting."
-    exit 2
+      echo " error: No configuration found. Aborting."
+      exit 3
   fi
   
   # === Define a base and glue everything together. ===
@@ -191,7 +191,7 @@ if [[ -n "${UI}" ]]; then
   else
       QEMU_ARGS+=( "${QEMU_DISPLAY_NONE_ARGS[@]}" )
   fi
-
+}
 # === Define functions for the actual QEMU controlling. ===
 start_qemu(){
     if [[ ! -f "${PID_FILE}" ]]; then
@@ -284,9 +284,36 @@ resume_qemu(){
         echo "Guest ${GUEST_NAME} is not running, nothing to resume."
     fi
 }
+print_help(){
+    echo " ======================================================================="
+    echo " control-vm.sh - simple QEMU/KVM vm manager"
+    echo "    version: ${__VERSION__}"
+    echo "    author Nils Freydank <nils.freydank@datenschutz-ist-voll-doof.de>"
+    echo "    license: MIT"
+    echo "    url: https://git.holgersson.xyz/nfr/control-vm"
+    echo " ======================================================================="
+    echo ""
+    echo " Use this tool in the following way:"
+    echo " ./control-vm.sh <name of your virtual machine> <operation>"
+    echo ""
+    echo " with operation as one of:"
+    echo "   start | shutdown | stop | connect | save | restore | pause | resume"
+    echo " or as one of the combinations:"
+    echo "   start+connect | stop+restore | restore+restart"
+    echo ""
+    echo " ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~"
+    echo " !   Note that stop means a forced stop - which can lead to data loss. !"
+    echo " ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~"
+}
 
 # === Parse the user input. ===
-# "$1 != nothing" is already checked earlier.
+# Provide a sanity check first.
+if [[ -z "${1}" ]]; then
+  echo " error: Please provide a guest name!"
+  print_help
+  exit 1
+else
+  set_params "${1}"
   case "${2}" in
       start+connect) start_qemu && connect_to_vm;;
       stop+restore) stop_qemu && restore_qemu;;
@@ -299,9 +326,10 @@ case "${2}" in
       restore) restore_qemu;;
       pause) pause_qemu;;
       resume) resume_qemu;;
-    *)  echo "Unknown Operation!"
-        echo "Use one of: start | shutdown | stop | connect | save | restore | pause | resume"
-        echo "or combinations: start+connect | stop+restore | restore+restart"
-        echo "Note that stop means a forced stop.";;
+      *)  echo " error: Unknown Operation!"
+          print_help
+          exit 2
+      ;;
   esac
+fi
 # vim:fileencoding=utf-8:ts=4:syntax=bash:expandtab

todo

@@ -7,4 +7,3 @@
 # 7. shared dir without smb, but via FUSE
 # 8. bash and zsh-completion
 # 9. don't rely on the PID to check if the VM is running, query socket?
-# 11. print a pretty help message and share on mastodon :)