python - 在Dockerfile中运行 “manage.py compilemessages”可得到 “django.db.utils.OperationalError: could not connect to server: No such file or directory”

Question

我有一个django项目的仓库，想从中创建一个Docker镜像。我也不想在git中存储任何已编译的文件，因此我尝试在Docker镜像创建过程中自动创建所有 Artifact 。
如果我插入:RUN python manage.py compilemessages -l en在我的Dockerfile中，我得到了(请注意所有依赖项都安装在主机上):

Traceback (most recent call last):
  File "manage.py", line 13, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 338, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 312, in execute
    django.setup()
  File "/usr/local/lib/python2.7/site-packages/django/__init__.py", line 18, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/usr/local/lib/python2.7/site-packages/django/apps/registry.py", line 115, in populate
    app_config.ready()
  File "/src/playpilot/apps.py", line 21, in ready
    for ct in ContentType.objects.all():
  File "/usr/local/lib/python2.7/site-packages/django/db/models/query.py", line 162, in __iter__
    self._fetch_all()
  File "/usr/local/lib/python2.7/site-packages/django/db/models/query.py", line 965, in _fetch_all
    self._result_cache = list(self.iterator())
...

File "/usr/local/lib/python2.7/site-packages/psycopg2/__init__.py", line 164, in connect
    conn = _connect(dsn, connection_factory=connection_factory, async=async)
django.db.utils.OperationalError: could not connect to server: No such file or directory
    Is the server running locally and accepting
    connections on Unix domain socket "/tmp/.s.PGSQL.5432"?

我通过在构建脚本中运行docker-compose(具有整个运行环境)来解决此问题

docker-compose up -d
docker-compose exec web ./manage.py compilemessages -l en
docker commit proj_web_1 image_name
docker-compose down

但这增加了构建时间，并且看起来是一个非常丑陋的解决方案。
manage.py不需要连接数据库即可执行此特定任务。
有没有一种方法可以运行 manage.py，因此它不会调用数据库后端？

Django版本:1.8

Answer 1

您的问题是，当您运行collectstatic时postgres容器已启动，但postgres本身尚未启动。阅读https://docs.docker.com/compose/startup-order/了解更多信息

您基本上需要做的是设置ENTRYPOINT，以检查postgres是否准备接受连接，这是我在项目中如何做的示例

#!/bin/sh
# NOTE: if there is no bash can cause
# standard_init_linux.go:190: exec user process caused "no such file or directory"

# https://docs.docker.com/compose/startup-order/
set -euo pipefail

WAIT_FOR_POSTGRES=${WAIT_FOR_POSTGRES:-true}

if [[ "$WAIT_FOR_POSTGRES" = true ]]; then
    DATABASE_URL=${DATABASE_URL:-postgres://postgres:postgres@postgres:5432/postgres}

    # convert to connection string
    # https://www.postgresql.org/docs/current/static/libpq-connect.html#LIBPQ-CONNSTRING
    POSTGRES_URL=${DATABASE_URL%%\?*}
    # https://www.gnu.org/software/bash/manual/bash.html#Shell-Parameter-Expansion
    POSTGRES_URL=${POSTGRES_URL/#postgis:/postgres:}

    # let postgres and other services (e.g. elasticsearch) to warm up...
    # https://www.caktusgroup.com/blog/2017/03/14/production-ready-dockerfile-your-python-django-app/
    until psql $POSTGRES_URL -c '\q'; do
        >&2 echo "Postgres is not available - sleeping"
        sleep 1
    done
    # >&2 echo "Postgres is up - executing command"
fi

if [[ $# -ge 1 ]]; then
    exec "$@"
else
    echo "Applying migrations"
    python manage.py migrate --noinput -v 0
    echo "Generate translations"
    python manage.py compilemessages --locale ru -v 0
    echo "Starting server"
    exec python manage.py runserver 0.0.0.0:8000
fi