How to modify volume files with host user inside container when using docker-compose

Question

I have a docker container managed by docker-compose that on startup will run a build script to add a bunch of files onto a volume mapped to a host folder, since the container is always running as root it keeps creating files which are root in the parent folder, how can I set docker-compose such that files created will be by the same user as the user who ran docker-compose up on the host file system?

docker-compose file

version: "2"
services:

  # Data API and authentication/authorization
  api:
    build:
      context: ../api/
      dockerfile: Dockerfile.dev
    hostname: api
    depends_on:
      - db
      - redis
    environment:
      - CORS_ORIGIN=http://localhost:3000,http://localhost:3001
      - DATABASE_URL=postgres://postgres@db:5432/dev
      - DATABASE_DEBUG=false
      - REDIS_URL=redis://redis:6379/0
      - SESSION_SECRET=wZjwhFtzQsd7r87W6AZw45Sm
      - FACEBOOK_ID=1821424564802638
      - FACEBOOK_SECRET=2339bdf25f236a42fc3a18280bf455e8
      - GOOGLE_ID=xxxxx.apps.googleusercontent.com
      - GOOGLE_SECRET=xxxxx
      - TWITTER_KEY=xxxxx
      - TWITTER_SECRET=xxxxx
    ports:
      - "8080:8080"
      - "127.0.0.1:9229:9229" # V8 inspector for tools/run.js
      - "127.0.0.1:9230:9230" # V8 inspector for src/server.js
    volumes:
      - yarn:/home/node/.cache/yarn
      - ../api/:/usr/src/app
    command: node tools/run.js # or, `node --inspect=0.0.0.0:9229 tools/run.js`

  # SQL and document data store
  db:
    image: postgres:9.6.5-alpine
    read_only: true
    tmpfs:
      - /tmp
      - /var/run/postgresql
    volumes:
      - db:/var/lib/postgresql/data
      - ./postgres-initdb.sh:/docker-entrypoint-initdb.d/initdb.sh
    # ports:
    #   - "127.0.0.1:5432:5432" # you can override it via docker-compose.override.yml

  # Distributed in-memory cache
  redis:
    image: redis:4.0.2-alpine
    read_only: true
    volumes:
      - redis:/data

volumes:
  db:
  redis:
  yarn:

dockerfile.dev on api directory

FROM node:8.6.0-alpine

# Set a working directory
WORKDIR /usr/src/app

# If you have native dependencies, you'll need extra tools
RUN apk add --no-cache make g++ python2 libsodium-dev && \
  npm install -g node-gyp && \
  mkdir -p /home/node/.cache/yarn && \
  chown -R node:node /home/node/.cache/yarn && \
  chmod 777 /home/node/.cache/yarn

VOLUME /home/node/.cache/yarn

Evgeniy Kuzmin · Accepted Answer · 2018-06-30 01:36:32Z

3

There is no straightforward way to do this, but you can create a user inside a container with the same User and Group id as your host user has. You can do this during docker-compose build using build arguments.

in dockerfile

ARG UID
ARG GID

RUN groupadd -g $GID %group_name% && useradd -u $UID -g $GID --create-home -s /bin/bash %user_name%

USER %user_name%

in docker-compose.yml

version: "2"
services:

  api:
    build:
      context: ../api/
      dockerfile: Dockerfile.dev
      args:
        UID: %your uid%
        GID: %you gid%

Update 1 (Automation)

In order to make this process easier for mulitple users you can automate it a bit.

in docker-compose.yml you can use variable substitution like this:

version: "2"
services:

  api:
    build:
      context: ../api/
      dockerfile: Dockerfile.dev
        args:
          UID: ${UID_VAR}
          GID: ${GID_VAR}

than you can write script, which generates .env file in repo for a particular user (suppose it's name is init.sh):

echo "UID_VAR=`id -u $USER`" > .env && echo "GID_VAR=`id -g $USER`" >> .env

So each your users will do something like this:

git clone repo
cd repo
./init.sh # generates .env
docker-compose build # earch user is have to build container because of GID and UID
docker-compose up

edited Jun 30, 2018 at 1:36

Evgeniy Kuzmin

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answered Oct 9, 2017 at 13:45

user1992836

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1 Comment

JasonY Over a year ago

I will have many users share this repository, does this mean they will each have to do this?

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