use-app.sh

#!/bin/bash
set -eu

git config apply.whitespace nowarn
git config core.filemode false


initiate_docker_compose_file(){

    if [[ ${use_my_own_app_yml} == true ]]; then
      if [[ ${orchestration_type} == 'stack' ]]; then
         echo "[NOTICE] As USE_MY_OWN_APP_YML is set 'true', we will use your customized 'docker-${orchestration_type}-${project_name}-original-${new_state}-ready.yml'"
         cp -f docker-${orchestration_type}-${project_name}-original-${new_state}-ready.yml docker-${orchestration_type}-${project_name}.yml || (echo "[ERROR] Failed to copy docker-${orchestration_type}-${project_name}-original-ready.yml" && exit 1)
         echo "[DEBUG] successfully copied docker-${orchestration_type}-${project_name}-original-${new_state}-ready.yml"
      else
         echo "[NOTICE] As USE_MY_OWN_APP_YML is set 'true', we will use your customized 'docker-${orchestration_type}-${project_name}-original-ready.yml'"
         cp -f docker-${orchestration_type}-${project_name}-original-ready.yml docker-${orchestration_type}-${project_name}.yml || (echo "[ERROR] Failed to copy docker-${orchestration_type}-${project_name}-original-ready.yml" && exit 1)
         echo "[DEBUG] successfully copied docker-${orchestration_type}-${project_name}-original-ready.yml"
      fi
    else
      if [[ ${orchestration_type} == 'stack' ]]; then
         cp -f docker-${orchestration_type}-app-original-${new_state}.yml docker-${orchestration_type}-${project_name}.yml || (echo "[ERROR] Failed to copy docker-${orchestration_type}-app-original.yml" && exit 1)
      else
        cp -f docker-${orchestration_type}-app-original.yml docker-${orchestration_type}-${project_name}.yml || (echo "[ERROR] Failed to copy docker-${orchestration_type}-app-original.yml" && exit 1)
      fi
      echo "[DEBUG] successfully copied docker-${orchestration_type}-app-original.yml"
    fi


    sleep 1
}

apply_env_service_name_onto_app_yaml(){

  check_yq_installed

  if [[ ${orchestration_type} == 'stack' ]]; then
      bin/yq -i "with(.services; with_entries(select(.key ==\"*-${new_state}\") | .key |= \"${project_name}-${new_state}\"))" docker-${orchestration_type}-${project_name}.yml || (echo "[ERROR] Failed to apply the green service name in the app YAML as ${project_name}." && exit 1)
     # bin/yq eval '(.services.[] | select(.image == "${PROJECT_NAME}:blue")).image |= \"${project_name}-blue\"' -i docker-${orchestration_type}-${project_name}-blue.yml  || (echo "[ERROR] Failed to apply image : ${project_name}-blue in the app YAML." && exit 1)
      bin/yq -i "(.services.\"${project_name}-${new_state}\").image = \"${project_name}:${new_state}\"" -i docker-${orchestration_type}-${project_name}.yml || (echo "[ERROR] Failed to apply image : ${project_name}-${new_state} in the app YAML." && exit 1)
  else
      echo "[NOTICE] PROJECT_NAME on .env is now being applied to docker-${orchestration_type}-${project_name}.yml."
      bin/yq -i "with(.services; with_entries(select(.key ==\"*-blue\") | .key |= \"${project_name}-blue\"))" docker-${orchestration_type}-${project_name}.yml || (echo "[ERROR] Failed to apply the blue service name in the app YAML as ${project_name}." && exit 1)
      sleep 2
      bin/yq -i "with(.services; with_entries(select(.key ==\"*-green\") | .key |= \"${project_name}-green\"))" docker-${orchestration_type}-${project_name}.yml || (echo "[ERROR] Failed to apply the green service name in the app YAML as ${project_name}." && exit 1)
  fi

}

apply_docker_compose_environment_onto_app_yaml(){

   check_yq_installed

   echo "[NOTICE] DOCKER_COMPOSE_ENVIRONMENT on .env is now being applied to docker-${orchestration_type}-${project_name}.yml."

   if [[ ${orchestration_type} == 'stack' ]]; then
    local states=("${new_state}")
   else
    local states=("blue" "green")
   fi

   for state in "${states[@]}"
   do
       bin/yq -i '.services.'${project_name}'-'${state}'.environment = []' docker-${orchestration_type}-${project_name}.yml
       bin/yq -i '.services.'${project_name}'-'${state}'.environment += "SERVICE_NAME='${state}'"' docker-${orchestration_type}-${project_name}.yml

       for ((i=1; i<=$(echo ${docker_compose_environment} | bin/yq eval 'length'); i++))
        do
           bin/yq -i '.services.'${project_name}'-'${state}'.environment += "'$(echo ${docker_compose_environment} | bin/yq -r 'to_entries | .['$((i-1))'].key')'='$(echo ${docker_compose_environment} | bin/yq -r 'to_entries | .['$((i-1))'].value')'"' docker-${orchestration_type}-${project_name}.yml
        done
   done

}

check_docker_compose_host_volumes_directories() {

    local volumes=$(echo "${docker_compose_selective_volumes[@]}" | tr -d '[]"')

    for volume in ${volumes}
    do
        # Extract the local directory path before the colon (:)
        local_dir="${volume%%:*}"

        # Check if the directory or file exists
        if [[ ! -f "$local_dir" && ! -d "$local_dir" ]]; then
            echo "[ERROR] The local path '$local_dir' specified in DOCKER_COMPOSE_SELECTIVE_VOLUMES does not exist. Exiting..."
            exit 1
        fi
    done
}

apply_docker_compose_volumes_onto_app_yaml(){

   check_yq_installed

   if [[ ${docker_compose_host_volume_check} == 'true' ]]; then
      check_docker_compose_host_volumes_directories
   fi

   echo "[NOTICE] DOCKER_COMPOSE_SELECTIVE_VOLUMES on .env is now being applied to docker-${orchestration_type}-${project_name}.yml."

   if [[ ${orchestration_type} == 'stack' ]]; then
    local states=("${new_state}")
   else
    local states=("blue" "green")
   fi

   for state in "${states[@]}"
   do
       #bin/yq -i '.services.'${project_name}'-'${state}'.volumes = []' ./docker-${orchestration_type}-${project_name}.yml

      for volume in "${docker_compose_selective_volumes[@]}"
      do
          bin/yq -i '.services.'${project_name}'-'${state}'.volumes += '${volume}'' ./docker-${orchestration_type}-${project_name}.yml
      done
   done

}


make_docker_build_arg_strings(){

   check_yq_installed

   echo "[NOTICE] make_docker_build_arg_strings for the 'docker build command'." >&2

   local re=""

   for ((i=1; i<=$(echo ${docker_build_args} | bin/yq eval 'length'); i++))
   do
       re="${re} --build-arg $(echo ${docker_build_args} | bin/yq -r 'to_entries | .['$((i-1))'].key')=$(echo ${docker_build_args} | bin/yq -r 'to_entries | .['$((i-1))'].value')"
   done

   echo ${re}
   return
}

# Image name: ${project_name} (utilizing 4 tags for Blue-Green deployment: ${project_name}:latest, ${project_name}:previous, ${project_name}:blue, ${project_name}:green)
load_app_docker_image() {

  if [ ${git_image_load_from} = "registry" ]; then

    echo "[NOTICE] Attempt to log in to the Registry."
    docker_login_with_params ${git_token_image_load_from_username} ${git_token_image_load_from_password} ${git_image_load_from_host}

    echo "[NOTICE] Pull the app image stored in the Registry."
    docker pull ${app_image_name_in_registry} || exit 1
    docker tag ${app_image_name_in_registry} ${project_name}:latest || exit 1
    docker rmi -f ${app_image_name_in_registry} || exit 1

  else

    echo "[NOTICE] Build the image with ${docker_file_location}/${docker_file_name} (using cache)"
    local env_build_args=$(make_docker_build_arg_strings)
    echo "[NOTICE] DOCKER_BUILD_ARGS on the .env : ${env_build_args}"
    echo "[NOTICE] DOCKER_BUILD_LABELS on the .env : ${docker_build_labels}"

    # Convert DOCKER_BUILD_LABELS to Docker --label arguments
    local label_args=""
    IFS=',' read -r -a labels <<< "$docker_build_labels"

    for label in "${labels[@]}"; do
      # Ensure labels are in correct format (e.g., key=value)
      formatted_label=$(echo "$label" | sed -e 's/^\[//' -e 's/\]$//' -e 's/^"//' -e 's/"$//' | xargs)

      # Only add to label_args if formatted_label is not empty
      if [[ -n "$formatted_label" ]]; then
        label_args+="--label $formatted_label "
      fi
    done

    # Trim whitespace and check if label_args is just "--label"
    if [[ $(echo "$label_args" | xargs) == "--label" ]]; then
      label_args=""
    fi

    echo "[NOTICE] Final DOCKER_BUILD_LABELS on the .env : ${label_args} "

    if [[ ${docker_layer_corruption_recovery} == true ]]; then
       echo "[NOTICE] Docker Build Command : docker build --no-cache --tag ${project_name}:latest ${label_args} ${env_build_args} -f ${docker_file_name} -m ${docker_build_memory_usage} ${docker_build_additional_raw_params} ."
       cd ${docker_file_location} && docker build --no-cache --tag ${project_name}:latest ${label_args} ${env_build_args} -f ${docker_file_name} -m ${docker_build_memory_usage} ${docker_build_additional_raw_params} . || exit 1
       cd -
    else
       echo "[NOTICE] Docker Build Command : docker build --build-arg DISABLE_CACHE=${CUR_TIME} --tag ${project_name}:latest ${label_args} --build-arg HOST_IP="${HOST_IP}" ${env_build_args} -f ${docker_file_name} -m ${docker_build_memory_usage} ${docker_build_additional_raw_params} ."
       cd ${docker_file_location} && docker build --build-arg DISABLE_CACHE=${CUR_TIME} --tag ${project_name}:latest ${label_args} --build-arg HOST_IP="${HOST_IP}" ${env_build_args} -f ${docker_file_name} -m ${docker_build_memory_usage} ${docker_build_additional_raw_params} . || exit 1
       cd -
    fi

  fi

  if [[ $(docker images -q ${project_name}:previous 2> /dev/null) == '' ]]
  then
     docker tag ${project_name}:latest ${project_name}:previous
  fi

  docker tag ${project_name}:latest ${project_name}:blue
  docker tag ${project_name}:latest ${project_name}:green
}

app_down_and_up(){

    if [[ ${orchestration_type} == 'stack' ]]; then
      echo "[NOTICE] Down & Up '${project_name}-${new_state} stack'."
      docker stack rm ${project_name}-${new_state} || echo "[NOTICE] The ${project_name}-${new_state} stack has been removed, if exists."
      docker stack deploy --compose-file docker-${orchestration_type}-${project_name}.yml ${project_name}-${new_state} || (echo "[ERROR] Service ${new_state} UP failure, however that does NOT affect the current deployment, as this is Blue-Green Deployment. (command : docker stack deploy --compose-file docker-${orchestration_type}-${project_name}.yml ${project_name})" && exit 1)

      # [TO DO] docker stack takes a long time to be up. it needs to use a good logic instead of sleep.
      sleep 20

    else
      echo "[NOTICE] Down & Up '${project_name}-${new_state} container'."
      docker-compose -f docker-${orchestration_type}-${project_name}.yml stop ${project_name}-${new_state} || echo "[NOTICE] The previous ${new_state} Container has been stopped, if exists."
      docker-compose -f docker-${orchestration_type}-${project_name}.yml rm -f ${project_name}-${new_state} || echo "[NOTICE] The previous ${new_state} Container has been removed, if exists."
      docker-compose -f docker-${orchestration_type}-${project_name}.yml up -d ${project_name}-${new_state} || (
          echo "[ERROR] App ${new_state} UP failure, however that does NOT affect the current deployment, as this is Blue-Green Deployment."
          # Check if use_my_own_app_yml is set to true
          if [[ ${use_my_own_app_yml} == true ]]; then
                echo "[INFO] Since use_my_own_app_yml is set to true, please note the following:"
                echo "1) The service name should remain the same as in the original YAML file, even if customization is possible."
                echo "2) For environment variables, set values directly in the .env file."
                echo "3) For volumes, also configure them directly in the .env file."
                exit 1
          else
              exit 1
          fi
      )

      echo "[NOTICE] '${project_name}-${new_state} container' : successfully UP."
    fi

}




# shellcheck disable=SC2120
check_availability_inside_container(){

  echo "[DEBUG] 'check_availability_inside_container' is about to run."  >&2

  check_state=${1}

  if [[ -z ${check_state} ]]
    then
      echo "[ERROR] the 'state' is NOT indicated on check_availability_inside_container."  >&2
      echo "false"
      return
  fi

  if [[ -z ${2} ]]
    then
      echo "[ERROR] there is no wait-for-it.sh timeout parameter."  >&2
      echo "false"
      return
  fi

  if [[ -z ${3} ]]
    then
      echo "[ERROR] there is no Health Check timeout parameter."  >&2
      echo "false"
      return
  fi

  local container_name=
  if [[ ${orchestration_type} == 'stack' ]]; then

    container_name=$(docker ps -q --filter "name=^${project_name}-${check_state}" | shuf -n 1);

    if [[ -z ${container_name} ]]; then
      echo "[ERROR] Any container is NOT checked in the ${project_name}-${check_state}_${project_name}-${check_state} service (Swarm). (container name : ${container_name}, command : docker ps -q --filter "name=^${project_name}-${check_state}" | shuf -n 1)"  >&2 && echo "false" && return
    fi

  else
    container_name=${project_name}-${check_state}
  fi

  local container_status
  container_status=$(docker inspect --format='{{.State.Status}}' ${container_name} 2>/dev/null || echo "unknown")

  # 상태 검사 및 처리
  if [ "$container_status" != "running" ] && [ "$container_status" != "created" ]; then
    echo "[ERROR] The status of Container (${container_name}) to run is '$container_status'. It has to be one of 'running' or 'created'" >&2
    echo "false"
    return
  fi

  if [[ $(check_command_in_container_or_fail ${container_name} "curl") != "true" ]]; then
         echo "false"
         return
  fi

  if [[ $(check_command_in_container_or_fail ${container_name} "bash") != "true" ]]; then
          echo "false"
          return
  fi


  echo "[NOTICE] [Internal Integrity Check : will deploy ${check_state}] Copy wait-for-it.sh into ${container_name}:${project_location}/wait-for-it.sh."  >&2
  docker cp ./wait-for-it.sh ${container_name}:${project_location}/wait-for-it.sh || (echo "[ERROR] Failed in copying (HOST : ./wait-for-it.sh) to (CONTAINER : ${project_location}/wait-for-it.sh)" >&2 &&  echo "false" && return)


  echo "[NOTICE] Check if the web server is responding by making a request inside the container (Name : ${container_name}). If library folders such as node_modules (Node.js), vendor (PHP) folders are NOT yet installed, the execution time of the ENTRYSCRIPT of your Dockerfile may be longer than usual (timeout: ${2} seconds)"  >&2


  # 1) APP is ON

  container_load_timeout=${2}

  echo "[NOTICE] [Internal Integrity Check : will deploy ${check_state}] In the ${container_name}  Container, conduct the Connection Check (localhost:${app_port} --timeout=${2}). (If this is delayed, run ' docker logs -f ${container_name} (compose), docker service ps ${project_name}-${check_state}_${project_name}-${check_state} (stack) ' to check the status."   >&2
  echo "[NOTICE] [Internal Integrity Check : will deploy ${check_state}] Current status (inside Container) : \n $(docker logs ${container_name})"   >&2
  echo "[NOTICE] wait_for_it ( https://github.com/vishnubob/wait-for-it ) will do the Check"  >&2
  local wait_for_it_re=$(docker exec -w ${project_location} ${container_name} ./wait-for-it.sh localhost:${app_port} --timeout=${2}) || (echo "[ERROR] Failed in running (CONTAINER : ${project_location}/wait-for-it.sh)" >&2 &&  echo "false" && return)
  if [[ $? != 0 ]]; then
      echo "[ERROR] Failed in getting the correct return from wait-for-it.sh. (${wait_for_it_re})" >&2
      echo "false"
      return
  else
      # 2) APP's health check
      echo "[NOTICE] [Internal Integrity Check : will deploy ${check_state}] In the ${container_name}  Container, conduct the Health Check."  >&2
      sleep 1

      local interval_sec=5

      local total_cnt=$((${container_load_timeout}/${interval_sec}))

      if [[ $((container_load_timeout%interval_sec)) != 0 ]]; then
        total_cnt=$((${total_cnt}+1))
      fi

      for (( retry_count = 1; retry_count <= ${total_cnt}; retry_count++ ))
      do
        echo -e "\033[1;35m[NOTICE] ${retry_count} round health check (curl -s -k ${app_https_protocol}://$(concat_safe_port localhost)/${app_health_check_path})... (timeout: ${3} sec)\033[0m" >&2
        response=$(docker exec ${container_name} sh -c "curl -s -k ${app_https_protocol}://$(concat_safe_port localhost)/${app_health_check_path} --connect-timeout ${3}")

        down_count=$(echo ${response} | grep -Ei ${bad_app_health_check_pattern} | wc -l)
        up_count=$(echo ${response} | grep -Ei ${good_app_health_check_pattern} | wc -l)

        if [[ ${down_count} -ge 1 || ${up_count} -lt 1 ]]
        then

            echo -e "\033[1;35m[WARNING] Unable to determine the health check response, or the status is not UP. Please check the following:\033[0m
            \033[1;35m1) Verify the REDIRECT_HTTPS_TO_HTTP parameter in .env\033[0m
            \033[1;35m2) Confirm your app's database connection\033[0m
            \033[1;35m3) Review your health check settings in .env.\033[0m
            \033[1;35m*Response:\033[0m ${response}
            \033[1;35m*Container:\033[0m ${container_name}
            \033[1;35m*Logs (last 25 lines):\033[0m $(docker logs --tail 25 ${container_name})" >&2


        else
             echo "[NOTICE] Internal health check of the application succeeded. (*Response: ${response})"  >&2
             break
        fi

        if [[ ${retry_count} -eq ${total_cnt} ]]
        then
          echo "[FAILURE] Health check failed in the end. (*Response:  ${response})" >&2
          echo "false"
          return
        fi

        echo "[NOTICE] ${retry_count}/${total_cnt} round Health Check failure. Retrying in ${interval_sec} secs..."  >&2
        for (( i = 1; i <= ${interval_sec}; i++ ));do echo -n "$i." >&2 && sleep 1; done
        echo "\n"  >&2

      done

     echo "true"
     return
 fi
}

check_availability_inside_container_speed_mode(){

  echo "[DEBUG] (Speed Mode) check_availability_inside_container"  >&2

  check_state=${1}

  if [[ -z ${1} ]]
    then
      echo "[ERROR] [Blue OR Green Alive Check : Currently ${check_state}] the 'state' NOT indicated on check_availability_inside_container "  >&2
      echo "false"
      return
  fi

  if [[ -z ${2} ]]
    then
      echo "[ERROR] [Blue OR Green Alive Check : Currently ${check_state}] there is no wait-for-it.sh timeout parameter."  >&2
      echo "false"
      return
  fi

  if [[ -z ${3} ]]
    then
      echo "[ERROR] [Blue OR Green Alive Check : Currently ${check_state}] there is no Health Check timeout parameter."  >&2
      echo "false"
      return
  fi

  local container_name=
  if [[ ${orchestration_type} == 'stack' ]]; then
    container_name=$(docker ps -q --filter "name=^${project_name}-${check_state}" | shuf -n 1);

    if [[ -z ${container_name} ]]; then
      echo "[ERROR] Any container is NOT checked in the ${project_name}-${check_state}_${project_name}-${check_state} service."  >&2 && echo "false" && return
    fi
  else
    container_name=${project_name}-${check_state}
  fi


  echo "[NOTICE] [Blue OR Green Alive Check : Currently checking ${check_state}] Copy wait-for-it.sh into ${container_name}:${project_location}/wait-for-it.sh."  >&2
  docker cp ./wait-for-it.sh ${container_name}:${project_location}/wait-for-it.sh


  #echo "[NOTICE] ${container_name} Check if the web server is responding by making a request inside the node-express-boilerplate-green container. If library folders such as node_modules (Node.js), vendor (PHP) folders are NOT yet installed, the execution time of the ENTRYSCRIPT of your Dockerfile may be longer than usual (timeout: ${2} seconds)"  >&2
  #sleep 3

  # 1) APP is ON

  container_load_timeout=${2}

  echo "[NOTICE] [Blue OR Green Alive Check : Currently checking ${check_state}] In the ${container_name}  Container, conduct the Connection Check (localhost:${app_port} --timeout=${2}). (If this is delayed, run ' docker logs -f ${container_name} (compose), docker service ps ${project_name}-${check_state}_${project_name}-${check_state} (stack) ' to check the status."   >&2
  echo "[NOTICE] [Blue OR Green Alive Check : Currently checking ${check_state}] Current status (inside Container) : \n $(docker logs ${container_name})"   >&2
  local wait_for_it_re=$(docker exec -w ${project_location} ${container_name} ./wait-for-it.sh localhost:${app_port} --timeout=${2}) || echo "[WARNING] Failed in Connection Check (running wait_for_it.sh). But, this function is for checking which container is running. we don't exit."   >&2
  if [[ $? != 0 ]]; then
      #echo "[ERROR] Failure in wait-for-it.sh. (${wait_for_it_re})" >&2
      echo "false"
      return
  else
      # 2) APP's health check
      echo "[NOTICE] [Blue OR Green Alive Check : Currently ${check_state}] In the ${container_name}  Container, conduct the Health Check."  >&2
      sleep 1

      local interval_sec=5

      local total_cnt=$((${container_load_timeout}/${interval_sec}))

      if [[ $((container_load_timeout%interval_sec)) != 0 ]]; then
        total_cnt=$((${total_cnt}+1))
      fi

      for (( retry_count = 1; retry_count <= ${total_cnt}; retry_count++ ))
      do
        echo "[NOTICE] [Blue OR Green Alive Check : Currently ${check_state}] ${retry_count} round health check (curl -s -k ${app_https_protocol}://$(concat_safe_port localhost)/${app_health_check_path})... (timeout : ${3} sec)"  >&2
        response=$(docker exec ${container_name} sh -c "curl -s -k ${app_https_protocol}://$(concat_safe_port localhost)/${app_health_check_path} --connect-timeout ${3}") || echo "[WARNING] [Blue OR Green Alive Check : Currently ${check_state}] Failed in Health Check. But, this function is for checking which container is running. we don't exit."   >&2

        down_count=$(echo ${response} | grep -Ei ${bad_app_health_check_pattern} | wc -l)
        up_count=$(echo ${response} | grep -Ei ${good_app_health_check_pattern} | wc -l)

        if [[ ${down_count} -ge 1 || ${up_count} -lt 1 ]]
        then

            echo ""  >&2

        else
             echo ""  >&2
             break
        fi

        if [[ ${retry_count} -eq ${total_cnt} ]]
        then
          echo "false"
          return
        fi

        #echo "[NOTICE] ${retry_count}/${total_cnt} round Health Check failure. Retrying in ${interval_sec} secs..."  >&2
        for (( i = 1; i <= ${interval_sec}; i++ ));do echo -n "$i." >&2 && sleep 1; done
        echo "\n"  >&2

      done

     echo "true"
     return
 fi
}

check_availability_out_of_container(){

  echo "[NOTICE] Check the http status code from the outside of the container. by calling '${app_url}/${app_health_check_path}'"  >&2

 sleep 1

  for retry_count in {1..6}
  do
    status=$(curl ${app_url}/${app_health_check_path} -o /dev/null -k -Isw '%{http_code}' --connect-timeout 10)
    available_status_cnt=$(echo ${status} | grep -Ei '^2[0-9]+|3[0-9]+$' | wc -l)

    if [[ ${available_status_cnt} -lt 1 ]]; then

      echo "Bad HTTP response in the ${new_state} app: ${status}"  >&2

      if [[ ${retry_count} -eq 5 ]]
      then
         echo "[ERROR] Health Check Failed. (If you are not accessing an external domain (=closed network setting environment), you need to check if APP_URL is the value retrieved by ifconfig on the Ubuntu host. Access to the ip output by the WIN ipconfig command may fail. Or you need to check the network firewall."  >&2
         echo "false"
         return
      fi

    else
      echo "[NOTICE] Success. (Status (2xx, 3xx) : ${status})"  >&2
      break
    fi

    echo "[NOTICE] Retry once every 3 seconds for a total of 8 times..."  >&2
    sleep 3
  done

  echo 'true'
  return

}


check_availability_out_of_container_speed_mode(){

  echo "[NOTICE] (Speed Mode) Check the http status code from the outside of the container. by calling '${app_url}/${app_health_check_path}'"  >&2

 sleep 1

  for retry_count in {1..3}
  do
    status=$(curl ${app_url}/${app_health_check_path} -o /dev/null -k -Isw '%{http_code}' --connect-timeout 10)
    available_status_cnt=$(echo ${status} | grep -Ei '^2[0-9]+|3[0-9]+$' | wc -l)

    if [[ ${available_status_cnt} -lt 1 ]]; then

      echo "Bad HTTP response in the ${new_state} app: ${status}"  >&2

      if [[ ${retry_count} -eq 2 ]]
      then
         echo "[ERROR] Health Check Failed. (If you are not accessing an external domain (=closed network setting environment), you need to check if APP_URL is the value retrieved by ifconfig on the Ubuntu host. Access to the ip output by the WIN ipconfig command may fail. Or you need to check the network firewall."  >&2
         echo "false"
         return
      fi

    else
      echo "[NOTICE] Success. (Status (2xx, 3xx) : ${status})"  >&2
      break
    fi

    echo "[NOTICE] Retry once every 3 seconds for a total of 8 times..."  >&2
    sleep 3
  done

  echo 'true'
  return

}