gettext, envsubst로 conf file의 env substitute

manticore conf 파일에 환경변수가 들어가는데 python 스크립트로 env들을 치환해주려고 했다.
문제는 docker compose로 컨테이너를 띄우는 도중에 바꿔주는 게 어려웠다.
이 방법은 github action 실행할 때 썼지만 지금 상황과는 맞지 않았고 불편했다.

"""
manticore_{SERVER_ENV}.conf 파일에 .env의 환경 변수를 replace해주는 스크립트
"""
import os
from dotenv import load_dotenv
from shutil import copyfile

SERVER_ENV = os.getenv("SERVER_ENV")
load_dotenv(verbose=True, dotenv_path=f".env.{SERVER_ENV}")

# Get the secret from .env
DB_HOST = os.getenv("DB_HOST")
DB_PORT = os.getenv("DB_PORT")
DB_USER = os.getenv("DB_USER")
DB_PASSWORD = os.getenv("DB_PASSWORD")
DB_NAME = os.getenv("DB_NAME")


def read_file():
    with open(f"./manticore/manticore_{SERVER_ENV}.conf", "r") as f:
        config_contents = f.read()
    return config_contents


def open_and_modify_file(config_contents):
    config_contents = config_contents.replace("DB_HOST", DB_HOST)
    config_contents = config_contents.replace("DB_PORT", DB_PORT)
    config_contents = config_contents.replace("DB_USER", DB_USER)
    config_contents = config_contents.replace("DB_PASSWORD", DB_PASSWORD)
    config_contents = config_contents.replace("DB_NAME", DB_NAME)

    write_env(config_contents)

    copyfile(f"./manticore/manticore_{SERVER_ENV}.conf", "./manticore/manticore.conf")


def write_env(config_contents):
    with open(f"./manticore/manticore_{SERVER_ENV}.conf", "w") as f:
        f.write(config_contents)


def restore_original_file():
    copyfile(
        "./manticore/manticore_tmp.conf", f"./manticore/manticore_{SERVER_ENV}.conf"
    )


def replace_manticore_conf():
    copyfile(
        f"./manticore/manticore_{SERVER_ENV}.conf", "./manticore/manticore_tmp.conf"
    )
    config_contents = read_file()
    open_and_modify_file(config_contents)
    # restore_original_file()
    os.remove("./manticore/manticore_tmp.conf")

python 스크립트 대신 envsubst 사용
envsubst를 사용하기 위해 dockerfile에 설치

# syntax=docker/dockerfile:experimental

FROM python:3.9-slim as python-base

RUN apt-get update \
&& apt-get install default-mysql-client gdal-bin libgdal-dev docker.io gettext -yqq

...

RUN touch ./manticore/_manticore.conf

manticore

source real_estate_source {
    type = pgsql
    sql_host = $DB_HOST
    sql_port = $DB_PORT
    sql_user = $DB_USER
    sql_pass = $DB_PASSWORD
    sql_db = $DB_NAME

    sql_query = select id, lot_number, road_name_address, name from real_estate

    sql_field_string = lot_number
    sql_field_string = road_name_address
    sql_field_string = name
}

.env엔 DB_HOST 등이 있어야 함

version: '3.7'
services:
  django:
    container_name: django
    build:
      context: .
      dockerfile: ./dockerfile-testing
    restart: always
    env_file: .env.testing
    ports:
      - "8000:8000"
    command:
      - sh
      - -c
      - |
        envsubst < ./manticore/manticore.conf.template > ./manticore/_manticore.conf
        export SERVER_ENV=testing
        gunicorn xxx.wsgi --bind 0.0.0.0:8000 --workers 4 --threads 4
    volumes:
      - .:/xxx
      - static_volume:/xxx/static
    network_mode: "host"

  manticore:
    container_name: manticore
    image: manticoresearch/manticore
    environment:
      - EXTRA=1
    env_file: .env.testing
    restart: always
    ports:
      - 127.0.0.1:9306:9306
      - 127.0.0.1:9308:9308
    ulimits:
      nproc: 65535
      nofile:
         soft: 65535
         hard: 65535
      memlock:
        soft: -1
        hard: -1
    volumes:
      - ./manticore/data:/var/lib/manticore
      - ./manticore/_manticore.conf:/etc/manticoresearch/_manticore.conf
      - ./manticore/log:/var/log/manticore
      - ./manticore/index:/var/index/manticore
    network_mode: "host"
    depends_on:
      - django

template 파일 내 ${}를 환경변수로 치환해서 표준 출력함
envsubst < ./manticore/manticore.conf.template

표준 출력된 내용을 실제 사용될 conf 파일에 씀
envsubst < ./manticore/manticore.conf.template > ./manticore/_manticore.conf

https://linuxhandbook.com/envsubst-command/