Specify uid & gid for mapping and add sudo group

Author: js-jslog

Dockerfile

@@ -32,6 +32,7 @@ RUN apt-get update && apt-get install -y -q --no-install-recommends \
         mysql-client \
         python \
         postgresql postgresql-contrib \
+        sudo \
     && rm -rf /var/lib/apt/lists/*
 
 # Install docker ce so that host docker instances can be manipulated from this env
@@ -60,7 +61,9 @@ RUN add-apt-repository ppa:jonathonf/vim -y \
 
 # Create developer user under which all development within the container
 # will be performed
-RUN useradd --create-home --shell /bin/bash developer
+RUN groupadd --gid 1000 developer
+RUN useradd --create-home --shell /bin/bash --uid 1000 --gid 1000 developer
+RUN usermod --append --groups sudo developer && echo "developer:developer" | chpasswd
 USER developer
 
 # Install users vim customisations. This requires that the .vimrc
@@ -115,4 +118,4 @@ COPY --chown=developer:developer templates/webpack-es6/ /home/developer/template
 COPY --chown=developer:developer dotfiles/.gitignore /home/developer/templates/webpack-es6/.
 COPY --chown=developer:developer dotfiles/.eslintrc.json /home/developer/templates/webpack-es6/.
 
-LABEL version="2.1.1"
+LABEL version="2.1.2"

README.md

@@ -1,17 +1,49 @@
 # development-env
 The files to build a docker container with the applications I use for development
 
-# Clone
+# Important
+The running image defaults to a user named "developer" with a uid of 1000.
+
+You will be running the container with the idea of having "developer" map directly to your user so that it can modify your files. If your user is not uid 1000 then you will need to make use of the docker `userns-remap` feature: https://docs.docker.com/engine/security/userns-remap/
+
+Configuration here requires that you modify the `/etc/subuid` and `/etc/subgid` files to map 1000 in the container to whatever your user uid is in the host.
+
+## eg uid 1010
+If your uid is 1010 then you will need to make sure that the uid's in the container are staggard by 10 in relation to your host. One way to achieve this is to start your `/etc/subuid` mappings from 9:
+
+```
+youruser:10:1000     # 0 in the container will map to 10 in the host
+```
+
+But this will mean that the root user (0) in the container will map to uid 9 in the host. I have made the "developer" user part of the sudo group so that we have the freedom to do whatever we want with the container. It is better to have 2 mappings with a 10 digit gap built in:
+
+```
+youruser:0:1000     # 0 - 999 inclusive
+youruser:1010:1000  # 1000 in the container will map to 1010 in the host
+```
+
+## gid
+A similar process needs to be performed for the `/etc/subgid` file.
+
+## Docker daemon config
+See the instructions in the link above to configure the daemon to run with this subordinate config in mind.
+
+## Motivation
+The purpose of creating a non-root user is not for security reasons. This is why I encourage the mapping of `youruser:0:...`. The purpose is becuase many applications don't run properly under root.
+
+# Usage
+## Clone
 ```
 git clone --recursive [email protected]:js-jslog/development-env.git
 ```
 
-# Build
+## Build
 ```
 docker build -t jslog/development-env --build-arg http_proxy --build-arg https_proxy --build-arg HTTP_PROXY --build-arg HTTPS_PROXY  .
 ```
 
-# Run
+## Run
 ```
 docker inspect jslog/development-env | grep runcommand
 ```
+