2024-08-08 installer script - master branch

1. Adopts recommended she-bang syntax.

2. Adds version number to banner (mainly as a visual aid when discussing
   installation issues on Discord).

3. Removes internal SCRIPT variable which has a dependency on whether
   the script is invoked directly or piped to bash.

4. No need to resolve absolute path for `IOTSTACK` variable. This just
   causes an error in green-fields situations.

5. Better messaging in `handle_exit()` so it is clear whether the script
   completed normally with no further work to do, or should be re-run.

6. Better handling of "logout required" situation. Rather than killing
   the immediate parent process (`$PPID`), now iterates the process
   ancestry to find the most-distant ancestor owned by the current user.
   For SSH connections this is typically the `sshd` spawned for the
   user. For console connections, it's typically the shell launched by
   the login process. This deals with the problem where a script (eg the
   menu) calling the installer script would be the immediate parent
   process, and it would be killed without necessarily causing the
   required logout to enable group membership changes to take effect.

7. Removes `is_running_OS_release()` function which was only being used
   to infer modern Python behaviour from "bookworm" (ie a hack) and
   which failed on Ubuntu.

8. Uses and documents use of `PIP_BREAK_SYSTEM_PACKAGES` variable which
   triggers the desired modern Python behaviour on systems which support
   it, being ignored otherwise.

Signed-off-by: Phill Kelley <[email protected]>

Author: Paraphraser

install.sh

@@ -1,8 +1,11 @@
-#!/bin/bash
+#!/usr/bin/env bash
+
+# version - MUST be exactly 7 characters!
+UPDATE="2024v02"
 
 echo "                                         "
-echo "  _____ ____ _______  _             _    "
-echo " |_   _/ __ \\__   __|| | installer | |   "
+echo "  _____ ____ _______  _  installer  _    "
+echo " |_   _/ __ \\__   __|| |  $UPDATE  | |  "
 echo "   | || |  | | | |___| |_ __ _  ___| | __"
 echo "   | || |  | | | / __| __/ _\` |/ __| |/ /"
 echo "  _| || |__| | | \\__ \\ || (_| | (__|   < "
@@ -21,18 +24,12 @@ echo "                                         "
 # overuse of sudo is a very common problem among new IOTstack users
 [ "$EUID" -eq 0 ] && echo "This script should NOT be run using sudo" && exit 1
 
-# the name of this script is
-SCRIPT=$(basename "$0")
-
 # this script should be run without arguments
-[ $# -ne 0 ] && echo "$SCRIPT parameter(s) $@ ignored"
+[ $# -ne 0 ] && echo "command line argument(s) $@ ignored"
 
 # assumption(s) which can be overridden
 IOTSTACK=${IOTSTACK:-"$HOME/IOTstack"}
 
-# form absolute path
-IOTSTACK=$(realpath "$IOTSTACK")
-
 # derived path(s) - note that the menu knows about most of these so
 # they can't just be changed without a lot of care.
 IOTSTACK_ENV="$IOTSTACK/.env"
@@ -113,7 +110,10 @@ function handle_exit() {
 	[ -d "$IOTSTACK" ] && echo "$1" >"$IOTSTACK_INSTALLER_HINT"
 
 	# inform the user
-	echo -n "$SCRIPT completed"
+	echo -n "install.sh completed"
+
+	# advise if should be re-run
+	[ $1 -ne 0 ] && echo -n " - but should be re-run"
 
 	# reboot takes precedence over logout
 	if [ "$REBOOT_REQUIRED" = "true" ] ; then
@@ -123,7 +123,16 @@ function handle_exit() {
 	elif [ "$LOGOUT_REQUIRED" = "true" ] ; then
 		echo " - a logout is required."
 		sleep 2
-		kill -HUP "$PPID"
+		# iterate ancestor processes
+		for ANCESTOR in $(ps -o ppid=) ; do
+			# find first process belonging to current user
+			if [ "$(ps -p $ANCESTOR -o user=)" = "$USER" ] ; then
+				# kill it
+				kill -HUP $ANCESTOR
+			fi
+		done
+		# should not reach this
+		sleep 2
 	fi
 
 	# exit as instructed
@@ -229,13 +238,6 @@ echo ""
 # is in the expected location, the necessary symlink can be created by
 # this script and then docker-compose will be installed "correctly".
 
-function is_running_OS_release() {
-	unset VERSION_CODENAME
-	[ -f "/etc/os-release" ] && eval $(grep "^VERSION_CODENAME=" /etc/os-release)
-	[ "$VERSION_CODENAME" = "$1" ] && return 0
-	return 1
-}
-
 function is_python_script() {
 	[ $(file -b "$1" | grep -c "^Python script") -gt 0 ] && return 0
 	return 1
@@ -305,13 +307,9 @@ else
 	echo "having installed docker and docker-compose without using the official"
 	echo "'convenience script'. You may be able to solve this problem by running"
 	if is_python_script "$COMPOSE_CMD_PATH" ; then
-		if is_running_OS_release bookworm ; then
-			echo "   \$ pip3 uninstall -y --break-system-packages docker-compose"
-			echo "   \$ sudo pip3 uninstall -y --break-system-packages docker-compose"
-		else
-			echo "   \$ pip3 uninstall -y docker-compose"
-			echo "   \$ sudo pip3 uninstall -y docker-compose"
-		fi
+		echo "   \$ export PIP_BREAK_SYSTEM_PACKAGES=1"
+		echo "   \$ pip3 uninstall -y docker-compose"
+		echo "   \$ sudo pip3 uninstall -y docker-compose"
 		echo "   (ignore any errors from those commands)"
 	else
 		echo "   \$ sudo apt purge -y docker-compose"
@@ -384,12 +382,8 @@ fi
 # implement menu requirements
 if [ -e "$IOTSTACK_MENU_REQUIREMENTS" ] ; then
 	echo -e "\nChecking and updating IOTstack dependencies (pip)" 
-	unset PYTHON_OPTIONS
-	if is_running_OS_release bookworm ; then
-		echo "Note: pip3 installs bypass externally-managed environment check"
-		PYTHON_OPTIONS="--break-system-packages"
-	fi
-	pip3 install -U $PYTHON_OPTIONS -r "$IOTSTACK_MENU_REQUIREMENTS"
+	echo "Note: pip3 installs bypass externally-managed environment check"
+	PIP_BREAK_SYSTEM_PACKAGES=1 pip3 install -U -r "$IOTSTACK_MENU_REQUIREMENTS"
 fi
 
 # trigger re-creation of venv on next menu launch. Strictly speaking,