/munetakaJupyterHub/Computer/2024/MailServer/WildDuck-II/.ipynb_checkpoints/00_install_global_functions

§2024-10-31
00_install_global_functions_variables.sh
#! /bin/bash

# These are all the common global variables and global functions.

AUT_HOSTNAME=`hostname`
# $ hostname --> return mail
export AUT_SAFETY=true

export AUT_HOME="${HOME}" # maybe a more robust way?

# COLOR VARIABLES
# colored variables
export RED='\033[0;31m'
export GREEN='\033[0;32m'
export ORANGE='\033[0;33m'
export YELLOW='\033[1;33m'
export BLUE='\033[0;34m'
export NC='\033[0m' # No Color

# GLOBAL FUNCTIONS

# -----------------fun_get_password()---------------------------
fun_get_password(){
# If we are not root, we should aquire the sudo password
# Declare PASSWORD as a local variable, if not it will be global
#     local PASSWORD <-- right after the function declaration

if [ `whoami` == 'root' ]
  then
    PASSWORD=''
  else
    # -n option is a flag that tells echo not to output 
    # a trailing newline at the end of the text.
    echo -n "GIMME your password! ($OURNAME):"
    # the read command is used to read input from the user. 
    # The -s option stands for "silent" and is used to prevent 
    # the input from being displayed on the terminal.
    read -s PASSWORD
    echo -e "\n"
fi
}
# 
# The export -f command is used to export a function to the environment, 
# making it available to subshells. 
#

# In Bash, variables defined inside a function are, by default, local to 
# that function. However, if a variable is defined without the local keyword, 
# it remains in the global scope and can be accessed outside the function.
# when you declare a variable as local within a Bash function, it should be done 
# at the beginning of the function, right after the function definition. 
export -f fun_get_password

# -----------fun_check_password_boolean()---------------------------------------
fun_check_password_boolean(){
# Check if the $PASSWORD is good or not

# TODO: if hostname can not be resolved (/etc/hosts misses 127.0.0.1)
# then sudo outputs 'cannot resolve hostname', so this check
# "obviously" fails.

# The sudo -k command is used to invalidate the user's cached credentials for sudo. 
# This means that the next time you run a command with sudo, you will be prompted to 
# enter your password again, even if you recently authenticated.
sudo -k #disable sudo timeout, will be prompted again for passowrd

#prime it
# When you use sudo -S, you typically echo the password 
# and pipe it into the sudo command. 
# &> /dev/null, this redirects both standard output (stdout) and standard error (stderr) 
# to /dev/null, effectively silencing any output from the command. 
echo $PASSWORD | sudo -S echo hello &> /dev/null

local RESULT=$(echo $PASSWORD | sudo -S sudo -n echo hello 2>&1)
if [ "$RESULT" == "hello" ]; then
  echo 'Correct password.'
  return 0
else
  echo 'Wrong password.'
  return 1
fi

}
export -f fun_check_password_boolean


# -----fun_check_password()-------------------------------------------------
fun_check_password(){
if ! fun_check_password_boolean; then
  echo -e "${RED}ERROR:${NC} Wrong password, we should quit now."
  exit 1
fi
}
export -f fun_check_password


# ------fun_get_user_variables_no_default()----------------------------------
fun_get_user_variables_no_default(){
# get REMOTE_SERVER_EMAIL, if not supplied, quit. No default.

local VARIABLES=("${!1}")
# local: This declares a local variable within a function
# while ${1} represents the value of the first positional argument passed to a script or function.
local TMP_DEFAULT
local TMP_USER
local TMP_READ

echo "Automatic timeout is 120 sec"

for i in ${VARIABLES[@]}; do
  TMP_DEFAULT=DEFAULT_$i
  echo -n "GIMMME the $i (username, eg: ${!TMP_DEFAULT}), no default value:"
  read -t 120 TMP_READ
  echo ""
  declare -g USER_$i=$TMP_READ
  TMP_USER=USER_$i

  if [ "${!TMP_USER}" == "" ]; then
    echo -n "${TMP_USER} can not be empty. Please give it again:"
    read -t 130 TMP_READ
    declare -g USER_$i=$TMP_READ
    TMP_USER=USER_$i
    if [ "${!TMP_USER}" == "" ]; then
      echo "Second try failed. Quitting..."
      exit 1
    fi
  fi
done

}
export -f fun_get_user_variables_no_default

# ---fun_get_user_variables_password()---------------------------
fun_get_user_variables_password(){
# get REMOTE_SERVER_PASSWORD, no default, suppress echoing back

#
# The line VARIABLES=("${!1}") in Bash is used to create an array called VARIABLES 
# that gets its values from the positional parameter specified by $1, where $1 is 
# the first argument passed to the function or script.
#

local VARIABLES=("${!1}")
local TMP_DEFAULT
local TMP_USER
local TMP_READ

echo "Automatic timeout is 120 sec"

for i in ${VARIABLES[@]}; do
  TMP_DEFAULT=DEFAULT_$i
  echo -n "GIMMME the $i (password, eg: ${!TMP_DEFAULT}), no default value:"
  read -t 120 -s TMP_READ
  echo ""
  declare -g USER_$i=$TMP_READ
  TMP_USER=USER_$i

  if [ "${!TMP_USER}" == "" ]; then
    echo -n "${TMP_USER} can not be empty. Please give it again:"
    read -t 130 -s TMP_READ
    declare -g USER_$i=$TMP_READ
    TMP_USER=USER_$i
    if [ "${!TMP_USER}" == "" ]; then
      echo "Second try failed. Quitting..."
      exit 1
    fi
  fi
done
}
export -f fun_get_user_variables_password

# --fun_get_user_variables()--------------------------------------------------
fun_get_user_variables(){
# get USER_HOST_PORT, if not supplied, autofill with DEFAULT_HOST_PORT, etc

local VARIABLES=("${!1}")
local TMP_DEFAULT
local TMP_USER
local TMP_READ

echo "Automatic timeout is 30 sec"

for i in ${VARIABLES[@]}; do
  TMP_DEFAULT=DEFAULT_$i
  echo -n "GIMMME the $i (default: ${!TMP_DEFAULT}):"
  read -t 30 TMP_READ
  echo ""
  declare -g USER_$i=$TMP_READ
  TMP_USER=USER_$i

  if [ "${!TMP_USER}" == "" ]; then
    declare -g USER_$i=${!TMP_DEFAULT}
  fi
done
}
export -f fun_get_user_variables

# ----fun_prepare_run_command()------------------------------
fun_prepare_run_command(){
# prepare the runcommand variable.
# Must be called before fun_echo_command and fun_run_command

# $(...):This is command substitution. It runs the command inside the parentheses 
# and captures its output. In this case, it's capturing the output of the cat command.
TEMPLATE=$(cat <<EOF
-e "ORIGINAL_COMMAND=RUNCOMMAND_TEMPLATE" \
$USER_IMAGE
EOF
)

RUNCOMMAND_ADDED_ENV=${RUNCOMMAND_ORIG//$USER_IMAGE/$TEMPLATE}
RUNCOMMAND_NOPASSWD=${RUNCOMMAND_ADDED_ENV//$PASSWORD/PASSWORD}
RUNCOMMAND=${RUNCOMMAND_ADDED_ENV//RUNCOMMAND_TEMPLATE/$RUNCOMMAND_NOPASSWD}

}
export -f fun_prepare_run_command

# ---fun_echo_command() -----------------------------------------------------
#
fun_echo_command(){
# echo the command which will be launched (fun_run_command())

echo ${RUNCOMMAND//$PASSWORD/PASSWORD}

}
export -f fun_echo_command

# ---fun_run_command() -------------------------------------------------------
fun_run_command(){
# execute the final command

# The eval command in Bash is used to execute arguments as a Bash command. 
# It takes a string as an argument, concatenates it into a command, and then 
# executes it. This can be useful when you need to construct commands dynamically.
# Backticks: The backticks around eval $RUNCOMMAND mean that the output of that 
# evaluated command will be captured and returned as a string.
echo `eval $RUNCOMMAND`
}
export -f fun_run_command


# --fun_print_help()------------------------------------------------------------
fun_print_help(){
USAGE=$(cat <<EOF

# Manual
# The main installation script is:
./install.sh domainname [hostname]
eg. ${GREEN}./install.sh amazeme.com mail.amazeme.com${NC}

There is a slight difference between domainname and hostname.

${ORANGE}Simplest case${NC}:
One server serves everything: company website, emails, webmails.
One ip address, and domainname is the same az hostname.
Eg. amazme.com

${GREEN}More general case${NC}:
The domainname is part of the email address:
username@domainname

The hostname is the actual machine name, eg. this machine
name is: `hostname`

On larger organizations, the company homepage is independent from
the mail servers. Or the webmail servers.
Eg. the company homepage is amazme.com [11.22.33.44],
the mail server is mail.amazme.com [11.22.33.43]

So domainname = amazme.com
hostname = mail.amazme.com

${RED}IP address${NC} case:
You can call this script with ip address instead of domain name:
./install.sh 11.22.33.44
(with the server's public IP address)
In that case both domainname and hostname becomes the IP address.
Dunno why anyone wanna that...

EOF
)

# echo -e for the colored output, "quotes" for the newline preserves
echo -e "$USAGE"
}
export -f fun_print_help

# ---function hook_script {---------------------------------------------
function hook_script {
    echo "#!/bin/bash
git --git-dir=/var/opt/$1.git --work-tree=\"/opt/$1\" checkout "\$3" -f
cd \"/opt/$1\"
rm -rf package-lock.json
npm install --production --no-optional --no-package-lock --no-audit --ignore-scripts --no-shrinkwrap --progress=false
sudo $SYSTEMCTL_PATH restart $1 || echo \"Failed restarting service\"" > "/var/opt/$1.git/hooks/update"
    chmod +x "/var/opt/$1.git/hooks/update"
}
export -f hook_script

# ---function hook_script_bower ----------------------------------------
function hook_script_bower {
    echo "#!/bin/bash
git --git-dir=/var/opt/$1.git --work-tree=\"/opt/$1\" checkout "\$3" -f
cd \"/opt/$1\"
rm -rf package-lock.json
npm install --progress=false
npm run bowerdeps
sudo $SYSTEMCTL_PATH restart $1 || echo \"Failed restarting service\"" > "/var/opt/$1.git/hooks/update"
    chmod +x "/var/opt/$1.git/hooks/update"
}
export -f hook_script_bower

# ---function log_script()----------------------------------------------------
function log_script {

SERVICE_NAME=$1

# Ensure required files and permissions
echo "d /var/log/${SERVICE_NAME} 0750 syslog adm" > /etc/tmpfiles.d/${SERVICE_NAME}-log.conf

# Redirect MongoDB log output from syslog to service specific log file
echo "if ( \$programname startswith \"$SERVICE_NAME\" ) then {
    action(type=\"omfile\" file=\"/var/log/${SERVICE_NAME}/${SERVICE_NAME}.log\")
    stop
}" > /etc/rsyslog.d/25-${SERVICE_NAME}.conf

# Setup log rotate
echo "/var/log/${SERVICE_NAME}/${SERVICE_NAME}.log {
    daily
    ifempty
    missingok
    rotate 7
    compress
    create 640 syslog adm
    su root root
    sharedscripts
    postrotate
        systemctl kill --signal=SIGHUP --kill-who=main rsyslog.service 2>/dev/null || true
    endscript
}" > /etc/logrotate.d/${SERVICE_NAME}

}