How to properly get code logs from container in host using docker compose and volumes

Question

I am trying to understand how to share logs generated by a toy project into a volume. The logs are generated inside a docker container.

For this, I am using docker-compose version 3. So far, I built the volume and the container with docker compose. However, when I check the volume I don't find any files coming from the container. Here is the project architecture:

Here is what is inside the docker-compose.yml:

version: '3'
services:


    #Chatbot Service
    test_bot:
        build: ./test_bot
        image: test_bot:1.0
        #restart: always
        expose:
            - "5000"
        ports:
            - "5000:5000"
        volumes:
            - test_volume:/app/test_bot
#            volume:
#              nocopy: true

volumes:
    test_volume:

networks:
    negusnet:
        ipam:
            config:
                - subnet: 172.192.10.0/16

    negus.jitsi:

Here is what is inside the dockerfile.yml:

FROM python:3.6-slim

#Enviroment variables creation
ENV TEST_HOME=/app/test_bot

# Run updates, install basics and cleanup
# - build-essential: Compile specific dependencies
# - git-core: Checkout git repos
RUN apt-get update -qq \
    && apt-get install -y --no-install-recommends build-essential git-core openssl libssl-dev libffi6 libffi-dev curl nano git wget\
    && apt-get clean \
    && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*

# use bash always
RUN rm /bin/sh && ln -s /bin/bash /bin/sh

#Define the path of home repository
WORKDIR ${TEST_HOME}


#Copy all files in existing negus_ai repository in docker
COPY . ${TEST_HOME}


RUN python3 ${TEST_HOME}/run_script.py

And finally, here is my test_script:

import logging
import time


logging.basicConfig(filename='Client_logs.log',
    level=logging.INFO,
    format='%(asctime)s.%(msecs)03d %(levelname)s %(module)s - %(funcName)s: %(message)s',
    datefmt='%Y-%m-%d %H:%M:%S')

if __name__ == '__main__':
    i=0
    while(True):
        i=i+1

        logging.info("yay is is "+str(i))
        time.sleep(30)

[EDIT1] Just to be clear, I don't want any manipulation involving getting inside the container or having to copy manually the logs from it to the host machine.

[EDIT2] I check the container using docker container inspect id. No volumes seems to be linked to it. The mount parameter is empty.

Look inside the container, and `find` where the log actually was written? — Michael Hampton, Apr 26 '19 at 21:41
Probably not. First, you need to figure out what the problem is. Then you can devise a solution. — Michael Hampton, Apr 27 '19 at 14:19
The log is where it should be in the container. It is called Client_logs.log — ChiPlusPlus, Apr 27 '19 at 20:41
What is "where it should be in the container"? That isn't a path. — Michael Hampton, Apr 27 '19 at 22:13
Did the volume you specified actually get mounted to the container? Try `docker inspect -f '{{ .Mounts }}' ` and look for it. — Michael Hampton, Apr 28 '19 at 15:30

score 0 · Accepted Answer · answered Apr 28 '19 at 16:13

The solution for the problem was a bit tricky. All I had to do was replace

RUN python3 ${TEST_HOME}/run_script.py

with :

ENTRYPOINT python3 ${TEST_HOME}/run_script.py

Apparently, the volume binding to the container is not made if we use the line with RUN.

How to properly get code logs from container in host using docker compose and volumes

1 Answers1