Docker-Node-DooD

A NodeJS Docker-out-of-Docker helper. The DooD aspect was taken pretty much directly from http://container-solutions.com/running-docker-in-jenkins-in-docker/.

Useful for when you need a Docker container or containers to interact with Docker, including the creation of other Docker containers.

Usage

Creating Docker containers

The bash script build.sh is used to create a base application image, and one or more applications as passed on the command line. The applications can either already exist within a ./applications directory, or can be GitHub repositories (using the form of organisation/repo or user/repo), or a mixture of both.

E.g.:

./build.sh fastbeanau/my-app-persistence-layer fastbeanau/my-app-api-layer fastbeanau/my-app-ui-layer 

But, that is a rather contrived example, as there is probably little reason for the UI layer to need access to Docker, and neither the persistence layer would likely require Docker access nor NodeJS, and thus both of those would be unsuitable for this.

Applications making use of this image are expected to include something similar to the following in their Dockerfile:

FROM node-dood-base

COPY  . /application/

RUN cd /application \
    && npm install --production

Node Utilities

A Node script containing a helper method is also included in this repository (and published to NPM as dood-utils).

npm install --save dood-utils

Within your scripts:

const dood = require('dood-utils');
const myLocalPort = 8888;

dood.getHostPortMappings((err, ports) => {
  console.log(`Server listening on local port ${ports[myLocalPort+'/tcp'][0].HostPort}`);
});

Notes

• Any ports exposed by the container will be randomly mapped and exposed on the Docker host. This mapping will change on container start & restart, you may wish to consider using a discovery/registry service if this is an issue. The NPM package dood-utils has a method to provide the current port mappings to the container.

• Specific configuration settings for individual container(s) (once created) can be set by using the docker update command, e.g.

docker update --restart=unless-stopped my-app-persistence-layer
docker update --restart=on-failure:10 my-app-api-layer my-app-ui-layer