构建的Docker映像无法访问postgreSQL

Question

我使用Django和PostgreSQL作为项目的不同容器。当我使用docker-compose up运行容器时，我的Django应用程序可以连接到PostgreSQL，但同样，当我用docker build . --file Dockerfile --tag rengine:$(date +%s)构建docker镜像时，镜像成功构建，但在entrypoint.sh上，它无法找到主机作为db。

我的docker撰写文件是

version: '3'
services:
db:
restart: always
image: "postgres:12.3-alpine"
environment:
- POSTGRES_DB=postgres
- POSTGRES_USER=postgres
- POSTGRES_PASSWORD=postgres
- POSTGRES_PORT=5432
ports:
- "5432:5432"
volumes:
- postgres_data:/var/lib/postgresql/data/
networks:
- rengine_network
web:
restart: always
build: .
command: python3 manage.py runserver 0.0.0.0:8000
volumes:
- .:/app
ports:
- "8000:8000"
depends_on:
- db
networks:
- rengine_network
networks:
rengine_network:
volumes:
postgres_data:

入口点

#!/bin/sh
if [ "$DATABASE" = "postgres" ]
then
echo "Waiting for postgres..."
while ! nc -z db 5432; do
sleep 0.1
done
echo "PostgreSQL started"
fi
python manage.py migrate
# Load default engine types
python manage.py loaddata fixtures/default_scan_engines.json --app scanEngine.EngineType
exec "$@"

和Dockerfile

# Base image
FROM python:3-alpine
# Labels and Credits
LABEL 
name="reNgine" 
author="Yogesh Ojha <[e-mail]>" 
description="reNgine is a automated pipeline of recon process, useful for information gathering during web application penetration testing."
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1
RUN apk update 
&& apk add --virtual build-deps gcc python3-dev musl-dev 
&& apk add postgresql-dev 
&& apk add chromium 
&& apk add git 
&& pip install psycopg2 
&& apk del build-deps
# Copy requirements
COPY ./requirements.txt /tmp/requirements.txt
RUN pip3 install -r /tmp/requirements.txt
# Download and install go 1.13
COPY --from=golang:1.13-alpine /usr/local/go/ /usr/local/go/
# Environment vars
ENV DATABASE="postgres"
ENV GOROOT="/usr/local/go"
ENV GOPATH="/root/go"
ENV PATH="${PATH}:${GOROOT}/bin"
ENV PATH="${PATH}:${GOPATH}/bin"
# Download Go packages
RUN go get -u github.com/tomnomnom/assetfinder github.com/hakluke/hakrawler github.com/haccer/subjack
RUN GO111MODULE=on go get -u -v github.com/projectdiscovery/httpx/cmd/httpx 
github.com/projectdiscovery/naabu/cmd/naabu 
github.com/projectdiscovery/subfinder/cmd/subfinder 
github.com/lc/gau
# Make directory for app
RUN mkdir /app
WORKDIR /app
# Copy source code
COPY . /app/
# Collect Static
RUN python manage.py collectstatic --no-input --clear
RUN chmod +x /app/tools/get_subdomain.sh
RUN chmod +x /app/tools/get_dirs.sh
RUN chmod +x /app/tools/get_urls.sh
RUN chmod +x /app/tools/takeover.sh
# run entrypoint.sh
ENTRYPOINT ["/app/docker-entrypoint.sh"]

当我运行构建镜像时，它在entrypoint.sh文件上说没有这样的主机数据库。

有人能帮我吗？我哪里错了？

Answer 1

根据注释，过程中出现错误

docker run rengine:1234,

因此，在这种情况下，错误是意料之中的，因为主机名db只能在docker compose网络中工作。在docker组合堆栈中，一个服务可以使用service name与另一个服务通信，但在docker run的情况下，两个容器都在隔离环境中运行。

你有两个选择来解决这个问题

• 运行DB容器并使用遗留链接将应用程序容器与DB链接

docker run -it --name db mydb_image
# now link application container
docker run -it --link db:db rengine:1234

现在，容器将能够与主机db通信。

• 第二个选项是创建docker network，然后在同一网络中运行两个容器

docker run -itd --network=mynetwork db
docker run -itd --network=mynetwork app

但是您已经在使用docker-compose了，所以最好使用docker-compose进行测试。