Script Development Snippet

.gitignore

## General Files/Folder to ignore
!README.md
*.properties
!example.properties
!example-logger.properties
logs
*.log
*.txt
.lastrun

### VS Code ###
.vscode/

### MacOS ###
.DS_Store

README.md

Script Development Snippet

Overview

This gist is a snippet for creating any scripts, it contains the default support for property env files and logger on specific location

Setup Guide

1. Create a respective env property files, as of now we support local.properties, dev.properties, stag.properties and prod.properties, you can use example.properties for default properties and on top of that, you can add more and update the script accordingly

2. Add your properties to respective property files and update the script accordingly to get the property

3. Create logger.properties from example-logger.properties file and update the logger path where you want to dump your logs

4. Now to run the script you can use any follows commands to run this script, before running just make sure all the script has executable permission (chmod +x script.sh logger.sh etc..)

   # Command
   > ./script.sh --target [ENV_NAME]
   # Examples
   ./script.sh # Default would be local env means local.properties will be used, make sure you have it
   ./script.sh --target dev # Targeting develop environment 
   ./script.sh --target stag # Targeting staging environment 
   ./script.sh --target prod # Targeting production environment
   

5. Now you can add your code in _start_ function in script.sh file.

6. That's it, Now, validate the logs folder and check if everything looks fine.

Cron Setup [Optional]

1. If you want to setup a crontab for this script, please use below command after crontab -e

   # Command (For Every 5 Minutes CRONJOB)
     */5 * * * * /[FULL_PATH_TO_SCRIPT]/script.sh --target [ENV_NAME]
   # Examples 1 (For Every 5 Minutes CRONJOB)
     */5 * * * * /opt/script/script.sh --target dev
   # Example 2 (This will run job at 12:00 am every day)
     0 0 * * * /opt/script/script.sh --target stag

TODO:

1. Improve Logger
2. UPDATE README.md

example-logger.properties

#==========================================================
# logger properties
#==========================================================
logger.path=logs
logger.prefix=logger
# LOGGER LEVELS : DEBUG, INFO, ERROR
logger.level=DEBUG

example.properties

#==========================================================
# Script properties (TODO: It will get converted into env based properties like dev.properties, stag.properties, prod.properties, local.properties)
#==========================================================
script.version=0.0.1-beta
script.env=local
script.name=zScriptName
script.timezone=Asia/Kolkata

logger.sh

#!/usr/bin/env bash

# Please Use Google Shell Style: https://google.github.io/styleguide/shell.xml

# ---- Start unofficial bash strict mode boilerplate
# http://redsymbol.net/articles/unofficial-bash-strict-mode/
set -o errexit  # always exit on error
set -o errtrace # trap errors in functions as well
set -o pipefail # don't ignore exit codes when piping output
set -o posix    # more strict failures in subshells
# set -x          # enable debugging

IFS=$'\n\t'
# ---- End unofficial bash strict mode boilerplate

# ASCII color constants:
NO_COLOR='\033[0m' # No Color
BLACK_COLOR='\033[0;30m'
CYAN_COLOR='\033[0;36m'
LIGHT_CYAN_COLOR='\033[1;36m'
GREEN_COLOR='\033[0;32m'
LIGHT_GREEN_COLOR="\033[1;32m"
RED_COLOR='\033[0;31m'
LIGHT_RED_COLOR='\033[1;31m'
BLUE_COLOR='\033[0;34m'
LIGHT_BLUE_COLOR='\033[1;34m'
YELLOW_COLOR='\033[0;33m'
LIGHT_YELLOW_COLOR='\033[1;33m'
PURPLE_COLOR='\033[0;35m'
LIGHT_PURPLE_COLOR='\033[0;35m'

# Method to return script self path (absolute path)
getAbsolutePath() {
    # echo $([[ $1 = /* ]] && echo "$1" || echo "$PWD/")
    echo "$(cd $(dirname "$1");pwd)"
}

SCRIPT_ABSOLUTE_PATH=$(getAbsolutePath "$0")
PROPERTY_FILE="$SCRIPT_ABSOLUTE_PATH/logger.properties" # env file properties

# Return property to use a a variable like env variables
getProperty() {
    PROP_KEY=$1
    PROP_VALUE=`cat $PROPERTY_FILE | grep "$PROP_KEY" | cut -d'=' -f2`
    echo $PROP_VALUE
}

# ------------------------------------------------------ LOGGER OPERATIONS ------------------------------------------------------ 

LOGGER_LEVEL=$(getProperty "logger.level")
LOGGER_PATH=$(getProperty "logger.path")
LOGGER_PREFIX=$(getProperty "logger.prefix")
LOGGER_TIMESTAMP=$(date +%s)
_LOGGER_INITIAL_="SCRIPT"
loggerSetup() {
    [ -d $LOGGER_PATH ] || mkdir -p $LOGGER_PATH
}

# If logger level is not set for console, we still have to show `last time script executed` and `script complted successfully`
ENABLED_ECHO=0 # Default disabled
if [[ ${LOGGER_LEVEL} != 'DEBUG' ]]; then 
    ENABLED_ECHO=1
fi

function _info_ {
    now=$(date +%s)
    _LOGGER_=$2
    if [[ $_LOGGER_ == "" ]]; then 
        _LOGGER_=$_LOGGER_INITIAL_
    fi
    echo "[${_LOGGER_}] [info]" `date -d @$now +%Y-%m-%dT%H:%M:%S` $1 >> "${LOGGER_PATH}/${LOGGER_PREFIX}_${LOGGER_TIMESTAMP}.log"
    if [[ ${LOGGER_LEVEL} == 'DEBUG' ]] || [[ ${LOGGER_LEVEL} == 'INFO' ]]; then 
        echo "[${_LOGGER_}] ${LIGHT_GREEN_COLOR}[info]"${LIGHT_BLUE_COLOR} `date -d @$now +%Y-%m-%dT%H:%M:%S` ${LIGHT_CYAN_COLOR}$1${NO_COLOR}
    fi
}

function _error_ {
    now=$(date +%s)
    _LOGGER_=$2
    if [[ $_LOGGER_ == "" ]]; then 
        _LOGGER_=$_LOGGER_INITIAL_
    fi
    echo "[${_LOGGER_}] [error]" `date -d @$now +%Y-%m-%dT%H:%M:%S` $1 >> "${LOGGER_PATH}/${LOGGER_PREFIX}_${LOGGER_TIMESTAMP}.log"
    if [[ ${LOGGER_LEVEL} == 'DEBUG' ]] || [[ ${LOGGER_LEVEL} == 'ERROR' ]]; then 
        echo "[${_LOGGER_}] ${LIGHT_RED_COLOR}[error]"${LIGHT_BLUE_COLOR} `date -d @$now +%Y-%m-%dT%H:%M:%S` ${LIGHT_CYAN_COLOR}$1${NO_COLOR}
    fi
}

# Setup logger
loggerSetup

script.sh

#!/usr/bin/env bash

source $(dirname "$0")/logger.sh
_info_ "##########################################    SCRIPT START    ##########################################"
ENV="local" # Default environment
# Read the command line arguments to know the ENV
while [[ "$#" -gt 0 ]]; do
    if [[ $1 == "--target"  ]] &&  [[ $2 == "local"  ]] || [[ $2 == "dev"  ]] || [[ $2 == "stag"  ]] || [[ $2 == "prod"  ]]; then
        ENV=$2
    fi
    break # Break the loop after first iteration only
done


# ----------------------------------   Global Variables Declarations  ----------------------------------

SCRIPT_ABSOLUTE_PATH=$(getAbsolutePath "$0")
PROPERTY_FILE="$SCRIPT_ABSOLUTE_PATH/$ENV.properties" # env file properties
# Variables
VERSION=$(getProperty "script.version")
ENV=$(getProperty "script.env")
SCRIPT_NAME=$(getProperty "script.name")
TIMEZONE=$(getProperty "script.timezone")

export TZ=$TIMEZONE
UTC_DATE_TIME=$(date -u)
LOCAL_DATE_TIME=$(date -d "$UTC_DATE_TIME")
_info_ "$SCRIPT_NAME ($VERSION) - $ENV env [TZ: $TIMEZONE]"
_info_ "Script Starting UTC: $UTC_DATE_TIME, LOCAL: $LOCAL_DATE_TIME"
_info_ "Property file path: $PROPERTY_FILE"

function _start_ {
    # CODE HERE
    _info_ "Actual Script Starting From Here" "FIRST_STRING_IN_LOGGER_LOG_LINE"
}

# ------------------------------------------------------ MAIN METHOD ------------------------------------------------------ 

# Main method which will start the execution
__main__ () {
    TIMEFORMAT='Execution Time: %R seconds.'
    time {
        now=$(date +%s) # Capture Script Execution Start DateTime
        LAST_EXECUTED=$now
        if [[ -f ./.lastrun ]]; then
            LAST_EXECUTED=$(cat ./.lastrun) # we can use to see when the script was last time executed or use to process new files after this last timestamp
        else
            touch ./.lastrun
            echo "$now" >./.lastrun
        fi
        if [[ $ENABLED_ECHO == 1 ]] && [[ $ENABLED_ECHO == 1 ]]  ; then
            echo "Last Session Executed: $(date -d @$LAST_EXECUTED 2>/dev/null || date -r $LAST_EXECUTED)"
        fi
        # Show when last time script got executed before starting execution
        _info_ "Last Session Executed: $(date -d @$LAST_EXECUTED 2>/dev/null || date -r $LAST_EXECUTED)"
        local start=$(date +%s%N) # Capture script execution start timestamp
        _start_
        local end=$(date +%s%N) # end timestamp
        _info_ "Elapsed time: $(($end-$start)) ns | $((($end-$start)/1000000)) ms | $(echo "scale=3; ($end - $start)/1000000000" | bc -l) seconds "
        echo "$now" >./.lastrun # store last time script executed
        _info_ "Script Execution Complete!"
        if [[ $ENABLED_ECHO == 1 ]]; then
            echo "Script Execution Complete!"
        fi   
    }
}

# Execution Start Point
__main__
_info_ "${SCRIPT_NAME} Script Execution Complete!"
_info_ "##########################################  SCRIPT COMPLETED  ##########################################"