Question

我对flask，postgres和docker非常陌生。我正在尝试对我们的应用程序进行docker化，以便新开发人员不必担心安装python依赖关系就可以开始开发。我目前有两个容器，一个用于flask应用程序，一个用于postgres db。我遇到的问题是，当我将两者组合在一起时，它们无法彼此连接。我已经定义了自己的网络，以确保它们在同一网络上运行，但这似乎仍无法解决问题。当我在容器外部运行flask应用程序并尝试连接到容器化的postgres db时，我没有任何问题，连接正常。

任何帮助将不胜感激预先感谢

flask应用程序的Dockerfile

FROM python:3.7-alpine3.7

LABEL maintainer="uwblueprint"
LABEL org.label-schema.schema-version="1.0"
LABEL org.label-schema.name="elevate-api"
LABEL org.label-schema.vcs-url="https://gitlab.com/uwblueprint/elevate-api/"
LABEL org.label-schema.vendor="UW Blueprint"

## Copy source and environment-config files.
COPY app/ ./app/
WORKDIR /app

COPY Pipfile Pipfile.lock ./

## Install external dependencies.
RUN apk add --no-cache libpq


## Install application dependencies.
RUN apk add --no-cache --virtual build-deps \
        gcc musl-dev postgresql-dev libffi-dev && \
    pip3 install --upgrade pip pipenv gunicorn && \
        pipenv --python 3.7 && \
        pipenv install --system --deploy && \
    apk del build-deps

EXPOSE 5000
CMD ["flask", "run"]

Docker Compose File

version: '3.7'
services:
  database:
    image: registry.gitlab.com/uwblueprint/elevate-api/postgres:latest
    build:
      context: ./external/postgres
      cache_from:
        - registry.gitlab.com/uwblueprint/elevate-api/postgres:latest
        - postgres:10.5-alpine
    container_name: database
    env_file: ./external/postgres/configs/.env
    volumes:
      - postgres.data:/var/lib/postgresql/data # persist data
    ports:
      - "5432:5432"
    networks:
      - "api_net"

  api:
    build: .
    ports:
      - "5000:5000"
    networks:
      - "api_net"
networks:
  api_net:
volumes:
  postgres.data:

Python SQL炼金术代码

import os
from flask_sqlalchemy import SQLAlchemy
from app import app

# Make sure that DB_PASS is an environment variable:
##if 'DB_PASS' not in os.environ:
##    raise EnvironmentError("Could not find environment variable 'DB_PASS',")

##user = os.environ.get("DB_USER", "robot")
user ="fakeUser"
password = "fakePassword"

##password = os.environ["DB_PASS"]
host = os.environ.get("DB_HOST", "0.0.0.0")
port = os.environ.get("DB_PORT", "5432")
name = os.environ.get("DB_NAME", "elevate")

# Configure flask-sqlalchemy.
app.config["SQLALCHEMY_DATABASE_URI"] = "postgresql://%s:%s@%s:%s/%s" % (
    user, password, host, port, name
)
app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = False

# TODO: Find the optimal pool recycle time for PostgreSQL.
app.config["SQLALCHEMY_POOL_RECYCLE"] = 7200  # in milliseconds

# The db object is aware of the Flask application lifecycle, and will do things
# like close the database session when a Flask request ends.
#
# This saves a lot of headaches compared to the plain SQLAlchemy library, where
# I kept running into issues about database-session related objects trying
# to access the session when I had closed it prematurely (due to SQLAlchemy's
# lazy-loading data acess methods).
db = SQLAlchemy(app)

Answer 1

将DB_HOST设置为“数据库”，这是容器的名称。

Answer 2

在docker-compose内部，您可以按服务名称在服务之间建立连接。您可以在documentation中阅读有关内容。

默认情况下，Compose为您的应用设置单个网络。服务的每个容器都加入默认网络，并且都可以被该网络上的其他容器访问，并且可以在与容器名称相同的主机名下被发现。

将host或DB_HOST的环境设置为database。 127.0.0.1无法正常工作。

docker-compose

2 个答案: