I want to write simple python application and put in docker conteiner with dockerfile. My dockerfile is:
FROM ubuntu:saucy
# Install required packages
RUN apt-get update
RUN DEBIAN_FRONTEND=noninteractive apt-get -y install python
RUN DEBIAN_FRONTEND=noninteractive apt-get -y install mysql-server python-mysqldb
# Add our python app code to the image
RUN mkdir -p /app
ADD . /app
WORKDIR /app
# Set the default command to execute
CMD ["python", "main.py"]
In my python application I only want to connect to the database. main.py look something like this:
import MySQLdb as db
connection = db.connect(
host='localhost',
port=3306,
user='root',
passwd='password',
)
When I built docker image with:
docker build -t myapp .
and run docker image with:
docker run -i myapp
I got error:
_mysql_exceptions.OperationalError: (2002, "Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)")
What is the problem?
Learn to set up and run Docker containers for databasesCreate a Docker Compose YAML file for a MySQL Docker container. Connect to the MySQL database, running on a container, using various methods. Create and run multiple versions of MySQL in Docker containers.
The problem is that you've never started the database - you need to explicitly start services in most Docker images. But if you want to run two processes in Docker (the DB and your python program), things get a little more complex. You either have to use a process manager like supervisor, or be a bit cleverer in your start-up script.
To see what I mean, create the following script, and call it cmd.sh
:
#!/bin/bash
mysqld &
python main.py
Add it to the Dockerfile:
FROM ubuntu:saucy
# Install required packages
RUN apt-get update
RUN DEBIAN_FRONTEND=noninteractive apt-get -y install python
RUN DEBIAN_FRONTEND=noninteractive apt-get -y install mysql-server python-mysqldb
# Add our python app code to the image
RUN mkdir -p /app
ADD . /app
WORKDIR /app
# Set the default command to execute
COPY cmd.sh /cmd.sh
RUN chmod +x /cmd.sh
CMD cmd.sh
Now build and try again. (Apologies if this doesn't work, it's off the top of my head and I haven't tested it).
Note that this is not a good solution; mysql will not be getting signals proxied to it, so probably won't shutdown properly when the container stops. You could fix this by using a process manager like supervisor, but the easiest and best solution is to use separate containers. You can find stock containers for mysql and also for python, which would save you a lot of trouble. To do this:
localhost
in your python code to mysql
or whatever you want to call your MySQL container.docker run -d --name mysql mysql
docker run myapp --link mysql:mysql
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