Bash examples - shows use of key=val parameter passing, error checking, functions, etc

deploy_config.sh

#!/bin/bash
#set -x

# source common function and variables
source "$(readlink -f $0 | xargs dirname)/shared"

REPO_DIR="${HOME}/NewDeploy/Repositories/Config_$(date +%Y%m%d%H%M%S)"

# check if another instance of this deployment is in progress
check_another_instance $(basename -- "$0")

start_release() {

    confirm_start

    [ ! -d "${REPO_DIR}" ] && { echo -e "${b_red}No repository present, exiting...${clear}"; exit 1; }
    
    git -C "${REPO_DIR}" checkout -q "${BRANCH}"
    [ ! $? -eq 0 ] && { echo -e "${b_red}Error checking out branch ${BRANCH}, exiting${clear}"; exit 1; }

    br=$(git -C "${REPO_DIR}" branch -v | grep '\*' | cut -d ' ' -f2)
    [ "${br}" != "${BRANCH}" ] && { echo -e "${b_red}Branch mis-match exiting...${clear}"; exit 1; }

    IFS=,
    for TARGET in $MACHINES
    do
        TARGET=$(echo "${TARGET}" | xargs echo -n)


        [ ! -d "${REPO_DIR}/host_configs/${TARGET}" ] && { echo -e "${b_red}[$(date)] no config path $REPO_DIR}/host_configs/${TARGET} exists, skipping...${clear}"; continue ; }

        # get Env of host if DEPLOY_ENV is not provided
        if [ -z "${DEPLOY_ENV}" ]
        then
            get_target_env "${TARGET}"
        else 
            CFG_ENV="${DEPLOY_ENV}"
        fi
        
        # go through common files and copy to the right place
        find ${REPO_DIR}/common/${CFG_ENV}/* -prune -type d | while IFS= read -r d; do
           folder=${d##*/}
           rsync -avz --delete $d/* ${TARGET}:./deploy/config_versions/config_${COMMIT}/$folder/
           [ ! $? -eq 0 ] && { echo -e "${b_red}Error Rsync commit folder to ${TARGET}, continuing to next host ${clear}"; continue ;}
        done

        ssh $TARGET "rm -f config; ln -sfn deploy/config_versions/config_${COMMIT} config;"
        [ ! $? -eq 0 ] && { echo -e "${b_red}Error removing config on ${TARGET}, continuing to next host ${clear}"; continue ;}

        echo -e "${green}Deployment on host $TARGET is complete${clear}"
       
    done
}

get_params "${@}"

# check # of given params
[ "$#" -lt 2 ] && { print_usage; exit 1; }

start_message "Config"

echo -e "${green}\nRemoving current Config Dir and git cloning Config repo..${clear}\n\n"
rm -rf "${REPO_DIR:?}"


COMMIT=$(git -C "${REPO_DIR}" rev-parse --short=7 origin/"${BRANCH}")
[ ! $? -eq 0 ] && { echo -e "${b_red}Error getting the Commit number from repository, exiting${clear}"; exit 1; }

# get list of targets from passed parameters
[ -n "${HOSTS}" ] && { MACHINES="${HOSTS}"; }
[ -n "${DEPLOY_ENV}" ] && { MACHINES="${hostlist[$DEPLOY_ENV]}"; }

if [ -n "${MACHINES}" ]; then start_release; else echo -e "${b_red}No machines provided${clear}"; fi 

exit 0;

shared

#!/bin/bash

# terminal colors
red="\e[0;91m"
green="\e[0;92m"
white="\e[0;97m"
bold="\e[1m"
clear="\e[0m"
b_red="${red}${bold}"
b_green="${green}${bold}"
b_white="${white}${bold}"


# Host list per Environment
declare -A hostlist
hostlist[PROD]="prod@web1, prod@web2"
hostlist[SIM]="sim@web4, sim@web6"
hostlist[QA]="qa@web9"

get_params(){

    PARAMS=""
    while (( "$#" )); do
    case "$1" in

        ## --silent NO PROMPT
        -s|--silent)
        SILENT=true
        shift
        ;;
        
        ## BRANCH
        -b|--branch)
        if [ -n "${2}" ] && [ ${2:0:1} != "-" ]; then
            BRANCH=$2
            shift 2
        else
            echo -e "${b_red}Error: Argument for $1 is missing${clear}" >&2
            exit 1
        fi
        ;;

        ## Deploy ENV
        -e|--environment)
        if [ -n "${2}" ] && [ ${2:0:1} != "-" ]; then
            DEPLOY_ENV=${2}
            
            # set environment to uppercase
            DEPLOY_ENV="${DEPLOY_ENV^^}"
            shift 2
        else
            echo -e "${b_red}Error: Argument for $1 is missing${clear}" >&2
            exit 1
        fi
        ;;

        ## specific Hostnames
        -h|--hosts)
        if [ -n "${2}" ] && [ ${2:0:1} != "-" ]; then
            HOSTS=$2
            shift 2
        else
            echo -e "${b_red}Error: Argument for $1 is missing${clear}" >&2
            exit 1
        fi
        ;;

        -*|--*=) # unsupported flags
        echo -e "${b_red}Error: Unsupported flag $1 ${clear}" >&2
        print_usage
        exit 1
        ;;

        *) # preserve positional arguments
        PARAMS="$PARAMS $1"
        shift
        ;;
    esac
    done
    # set positional arguments in their proper place
    eval set -- "${PARAMS}"

    # sanity checks
    [[ -n "${HOSTS}" && -n "${DEPLOY_ENV}" ]] && { echo -e "${b_red}Cannot have both Environment and Hosts, provide one or the other. exiting..${clear}"; exit 1; }
    [[ -z "${HOSTS}" && -z "${DEPLOY_ENV}" ]] && { echo -e "${b_red}You must provide either an Environment or a Host list '--environment PROD or --hosts prod@qweb1,prod@qweb2'. exiting..${clear}"; exit 1; }

    [ -z "${BRANCH}" ] && { echo -e "${b_red}You must provide a Branch to pull for this repository '--branch QA'. exiting..${clear}"; exit 1; }
}


print_usage() {
    printf '%.s-' {1..100}
    echo -e "\nusage: $0 --branch [QA|master] --environment [PROD|SIM|QA|prod@web1 ...] <optional: --silent (no confirmation prompt)> "
    echo -e "\nparameter options: \n -b | --branch\n -e | --environment\n -h | --hosts [comma separted hostlist, cannot be used along with Environment]\n -s | --silent (boolean)"
    echo -e "\n${b_white}Example: $0 --branch QA --environment SIM --silent${clear}"
    echo -e "${b_white}Example: $0 --branch QA --hosts prod@web1,sim@web5${clear}\n"
}

get_target_env() {
    for ENV in "${!hostlist[@]}"
    do
        hosts=${hostlist[$ENV]}
        IFS=,
        for host in ${hosts}
        do
            host=$(echo $host | xargs echo -n)
            if [ "${host}" == "${1}" ]
            then
                CFG_ENV=$ENV
                break
            fi
        done
    done
}

confirm_start() {
    if [[ $SILENT = true ]]
    then
        echo -e "\n${green}--silent provided. skipping confirmation${clear}\n"
    else
        echo -e "\n\nAre you ready to release ${b_green}${BRANCH}${clear} branch, commit number ${b_green}${COMMIT}${clear} to the following machine(s) ${b_green}${MACHINES}${clear}\n\nType ${b_white}y${clear} to proceed\n"
        read -r resp
        [ "${resp}" != "y" ] && { echo -e "${b_red}Not confirmed, exiting..${clear}"; exit 1; }
    fi
}

start_message() {
    if [[ $SILENT = true ]]
    then
        echo -e "\n${green}--silent provided. skipping confirmation${clear}\n"
    else
        echo -e "\n\n[$(date)]\n\nThis will deploy ${b_white}$1${clear} to hosts\nType ${b_white}y${clear} to proceed\n"
        read -r resp
        [ "${resp}" != "y" ] && { echo -e "${b_red}Not confirmed, exiting..${clear}"; exit 1; }
    fi
}

check_another_instance() {
    if pidof -x "${1}" -o $$ >/dev/null;then
        echo -e "${b_red}An another instance of this script is already running, please clear all the sessions of this script before starting a new session${clear}"
        exit 1
    fi
}